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Deng X, He J, Zou Z, Yang X. A model of the spatiotemporal distribution of ozone-squalene reaction and ozonolysis by-products from human body. JOURNAL OF HAZARDOUS MATERIALS 2024; 479:135648. [PMID: 39191011 DOI: 10.1016/j.jhazmat.2024.135648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 08/23/2024] [Accepted: 08/23/2024] [Indexed: 08/29/2024]
Abstract
Emissions of ozone and its by-products from ozonolysis on human surfaces lead to indoor air pollution. However, the spatiotemporal distribution of such emissions in indoor environments remains unclear, which may introduce bias when assessing human exposure to ozone and ozonolysis byproducts. This study developed a computational fluid dynamics model to describe the physical and chemical processes involved in the emission of ozone-dependent volatile organic compounds from the human body. The results showed that the reaction probability of ozone in the human body depends on the ozone concentration in the bulk air. For ozone concentrations ranging from 28 ppb to 200 ppb, the reaction probabilities ranged from 5.9 × 10-5 to 1.5 × 10-4. The concentrations of ozone and ozonolysis byproducts obtained from the experimental measurements were used for model validation. The ozonolysis by-products were found to be uniformly distributed in the chamber, whereas the ozone distribution showed less uniformity. The ozone concentration near the human surface was approximately 30 %∼50 % of that in the ambient air. Overall, a model was developed to understand the effect of ozone-surface interactions on indoor air quality. This model can be applied to analyze human exposure to ozone and ozonolysis byproducts and for health risk assessment in built environments.
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Affiliation(s)
- Xiaorui Deng
- Department of Building Science, Tsinghua University, Beijing, China
| | - Junzhou He
- Department of Power Engineering, North China Electric Power University, Baoding, China.
| | - Ziwei Zou
- Department of Building Science, Tsinghua University, Beijing, China
| | - Xudong Yang
- Department of Building Science, Tsinghua University, Beijing, China.
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2
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Johnson KN, Li Y, Ezell MJ, Lakey PSJ, Shiraiwa M, Finlayson-Pitts BJ. Elucidating gas-surface interactions relevant to atmospheric particle growth using combined temperature programmed desorption and temperature-dependent uptake. Phys Chem Chem Phys 2024; 26:23264-23276. [PMID: 39205494 DOI: 10.1039/d4cp02528h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Understanding growth mechanisms for particles in air is fundamental to developing a predictive capability for their impacts on human health, visibility, and climate. In the case of highly viscous semi-solid or solid particles, the likelihood of impinging gases being taken up to grow the particle will be influenced by the initial uptake coefficient and by the residence time of the adsorbed gas on the surface. Here, a new approach that combines Knudsen cell capabilities for gas uptake measurements with temperature programmed desorption (TPD) for binding energy measurements of gases is described. The application of this unique capability to the uptake of organic gases on silica demonstrates its utility and the combination of thermodynamic and kinetic data that can be obtained. Lower limits to the initial net uptake coefficients at 170 K are (3.0 ± 0.6) × 10-3, (4.9 ± 0.6) × 10-3 and (4.3 ± 0.8) × 10-3 for benzene, 1-chloropentane, and methanol, respectively, and are reported here for the first time. The uptake data demonstrated that the ideal gas lattice model was appropriate, which informed the analysis of the TPD data. From the thermal desorption measurements, desorption energies of 34.6 ± 2.5, 45.8 ± 5.5, and 40.0 ± 5.6 kJ mol-1 (errors are 1σ) are obtained for benzene, 1-chloropentane, and methanol, respectively, and show good agreement with previously reported measurements. A multiphase kinetics model was applied to quantify uptake, desorption, and diffusion through the particle multilayers and hence extract desorption kinetics. Implications for uptake of organics on silica surfaces in the atmosphere and the utility of this system for determining relationships between residence times of organic gases and particle surfaces of varying composition are discussed in the context of developing quantitative predictions for growth of aerosol particles in air.
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Affiliation(s)
- Kristen N Johnson
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Yixin Li
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Michael J Ezell
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Pascale S J Lakey
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, CA 92697-2025, USA.
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3
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Yang S, Licina D. Nanocluster Aerosols from Ozone-Human Chemistry Are Dominated by Squalene-Ozone Reactions. ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2024; 11:716-722. [PMID: 39006814 PMCID: PMC11238579 DOI: 10.1021/acs.estlett.4c00289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/14/2024] [Accepted: 06/10/2024] [Indexed: 07/16/2024]
Abstract
Nanocluster aerosols (NCAs, <3 nm particles) are associated with climate feedbacks and potentially with human health. Our recent study revealed NCA formation owing to the reaction of ozone with human surfaces. However, the underlying mechanisms driving NCA emissions remain unexplored. Squalene is the most abundant compound in human skin lipids that reacts with ozone, followed by unsaturated fatty acids. This study aims to examine the contribution of the squalene-ozone reaction to NCA formation and the influence of ozone and ammonia (NH3) levels. In a climate-controlled chamber, we painted squalene and 6-hexadecenoic acid (C16:1n6) on glass plates to facilitate their reactions with ozone. The squalene-ozone reaction was further investigated at different ozone levels (15 and 90 ppb) and NH3 levels (0 and 375 ppb). The results demonstrate that the ozonolysis of human skin lipid compounds contributes to NCA formation. With a typical squalene-C16:1n6 ratio found in human skin lipids (4:1), squalene generated 40 times more NCAs than did C16:1n6 and, thus, dominated NCA formation. More NCAs were generated with increased ozone levels, whereas increased NH3 levels were associated with the stronger generation of larger NCAs but fewer of the smallest ones. This study experimentally confirms that NCAs are primarily formed from squalene-ozone reactions in ozone-human chemistry.
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Affiliation(s)
- Shen Yang
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Dusan Licina
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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4
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Deng H, Qiu J, Zhang R, Xu J, Qu Y, Wang J, Liu Y, Gligorovski S. Ozone Chemistry on Greasy Glass Surfaces Affects the Levels of Volatile Organic Compounds in Indoor Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:8393-8403. [PMID: 38691770 DOI: 10.1021/acs.est.3c08196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
The chemistry of ozone (O3) on indoor surfaces leads to secondary pollution, aggravating the air quality in indoor environments. Here, we assess the heterogeneous chemistry of gaseous O3 with glass plates after being 1 month in two different kitchens where Chinese and Western styles of cooking were applied, respectively. The uptake coefficients of O3 on the authentic glass plates were measured in the dark and under UV light irradiation typical for indoor environments (320 nm < λ < 400 nm) at different relative humidities. The gas-phase product compounds formed upon reactions of O3 with the glass plates were evaluated in real time by a proton-transfer-reaction quadrupole-interface time-of-flight mass spectrometer. We observed typical aldehydes formed by the O3 reactions with the unsaturated fatty acid constituents of cooking oils. The formation of decanal, 6-methyl-5-hepten-2-one (6-MHO), and 4-oxopentanal (4-OPA) was also observed. The employed dynamic mass balance model shows that the estimated mixing ratios of hexanal, octanal, nonanal, decanal, undecanal, 6-MHO, and 4-OPA due to O3 chemistry with authentic grime-coated kitchen glass surfaces are higher in the kitchen where Chinese food was cooked compared to that where Western food was cooked. These results show that O3 chemistry on greasy glass surfaces leads to enhanced VOC levels in indoor environments.
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Affiliation(s)
- Huifan Deng
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
- Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
- Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jia Qiu
- Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering and Center for Environment and Health, Peking University, Beijing 100871, China
| | - Runqi Zhang
- Department of Materials Environmental Engineering, Shanxi Polytechnic College, Shanxi 237016, China
| | - Jinli Xu
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
- Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
- Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuekun Qu
- Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering and Center for Environment and Health, Peking University, Beijing 100871, China
| | - Jixuan Wang
- Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering and Center for Environment and Health, Peking University, Beijing 100871, China
| | - Yingjun Liu
- Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering and Center for Environment and Health, Peking University, Beijing 100871, China
| | - Sasho Gligorovski
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
- Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
- Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China
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5
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Langer S, Weschler CJ, Bekö G, Morrison G, Sjöblom A, Giovanoulis G, Wargocki P, Wang N, Zannoni N, Yang S, Williams J. Squalene Depletion in Skin Following Human Exposure to Ozone under Controlled Chamber Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:6693-6703. [PMID: 38577981 DOI: 10.1021/acs.est.3c09394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
A major component of human skin oil is squalene, a highly unsaturated hydrocarbon that protects the skin from atmospheric oxidants. Skin oil, and thus squalene, is continuously replenished on the skin surface. Squalene is also quickly consumed through reactions with ozone and other oxidants. This study examined the extent of squalene depletion in the skin oils of the forearm of human volunteers after exposure to ozone in a climate chamber. Temperature, relative humidity (RH), skin coverage by clothing, and participants' age were varied in a controlled manner. Concentrations of squalene were determined in skin wipe samples collected before and after ozone exposure. Exposures to ozone resulted in statistically significant decreases in post-exposure squalene concentrations compared to pre-exposure squalene concentrations in the skin wipes when squalene concentrations were normalized by concentrations of co-occurring cholesterol but not by co-occurring pyroglutamic acid (PGA). The rate of squalene loss due to ozonolysis was lower than its replenishment on the skin surface. Within the ranges examined, temperature and RH did not significantly affect the difference between normalized squalene levels in post-samples versus pre-samples. Although not statistically significant, skin coverage and age of the volunteers (three young adults, three seniors, and three teenagers) did appear to impact squalene depletion on the skin surfaces.
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Affiliation(s)
- Sarka Langer
- IVL Swedish Environmental Research Institute, Environmental Chemistry, 40014 Göteborg, Sweden
- Chalmers University of Technology, Department of Architecture and Civil Engineering, Division Building Services Engineering, 412 96 Göteborg, Sweden
| | - Charles J Weschler
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey 08854, United States
- International Centre for Indoor Environment and Energy, Department of Environmental and Resource Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Gabriel Bekö
- International Centre for Indoor Environment and Energy, Department of Environmental and Resource Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
- Healthy and Sustainable Built Environment Research Centre, Ajman University, P.O. Box 346 Ajman, United Arab Emirates
| | - Glenn Morrison
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7431, United States
| | - Ann Sjöblom
- IVL Swedish Environmental Research Institute, Environmental Chemistry, 40014 Göteborg, Sweden
| | - Georgios Giovanoulis
- IVL Swedish Environmental Research Institute, Environmental Chemistry, 40014 Göteborg, Sweden
| | - Pawel Wargocki
- International Centre for Indoor Environment and Energy, Department of Environmental and Resource Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Nijing Wang
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Nora Zannoni
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany
| | - Shen Yang
- Human-Oriented Built Environment Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Jonathan Williams
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, 55128 Mainz, Germany
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6
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Fahy WD, Wania F, Abbatt JPD. When Does Multiphase Chemistry Influence Indoor Chemical Fate? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:4257-4267. [PMID: 38380897 DOI: 10.1021/acs.est.3c08751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Human chemical exposure often occurs indoors, where large variability in contaminant concentrations and indoor chemical dynamics make assessments of these exposures challenging. A major source of uncertainty lies in the rates of chemical transformations which, due to high surface-to-volume ratios and rapid air change rates relative to rates of gas-phase reactions indoors, are largely gas-surface multiphase processes. It remains unclear how important such chemistry is in controlling indoor chemical lifetimes and, therefore, human exposure to both parent compounds and transformation products. We present a multimedia steady-state fugacity-based model to assess the importance of multiphase chemistry relative to cleaning and mass transfer losses, examine how the physicochemical properties of compounds and features of the indoor environment affect these processes, and investigate uncertainties pertaining to indoor multiphase chemistry and chemical lifetimes. We find that multiphase reactions can play an important role in chemical fate indoors for reactive compounds with low volatility, i.e., octanol-air equilibrium partitioning ratios (Koa) above 108, with the impact of this chemistry dependent on chemical identity, oxidant type and concentration, and other parameters. This work highlights the need for further research into indoor chemical dynamics and multiphase chemistry to constrain human exposure to chemicals in the built environment.
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Affiliation(s)
- William D Fahy
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Frank Wania
- Department of Physical and Environmental Sciences, University of Toronto at Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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7
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Kvasnicka J, Cohen Hubal EA, Diamond ML. Modeling clothing as a secondary source of exposure to SVOCs across indoor microenvironments. JOURNAL OF EXPOSURE SCIENCE & ENVIRONMENTAL EPIDEMIOLOGY 2024; 34:376-385. [PMID: 38129669 PMCID: PMC11144090 DOI: 10.1038/s41370-023-00621-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 11/27/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Evidence suggests that clothing can influence human exposure to semi-volatile organic compounds (SVOCs) through transdermal uptake and inhalation. OBJECTIVES The objectives of this study were [1] to investigate the potential for clothing to function as a transport vector and secondary source of gas-phase SVOCs across indoor microenvironments, [2] to elucidate how clothing storage, wear, and laundering can influence the dynamics of transdermal uptake, and [3] to assess the potential for multiple human occupants to influence the multimedia dynamics of SVOCs indoors. METHODS A computational modeling framework (ABICAM) was expanded, applied, and evaluated by simulating and augmenting two "real-world" chamber experiments. A primary strength of this framework was its representation of occupants and their clothing as unique entities with the potential for location changes. RESULTS Estimates of transdermal uptake of diethyl phthalate (DEP) and di(n-butyl) phthalate (DnBP) were generally consistent with those extrapolated from measured concentrations of urinary metabolites, and those predicted by two other mechanistic models. ABICAM predicted that clean clothing (long sleeves, long pants, and socks, 100% cotton, 1 mm thick) readily accumulated DEP (6900-9700 μg) and DnBP (4500-4800 μg) from the surrounding chamber air over 6 h of exposure to average concentrations of 233 (DEP) and 114 (DnBP) μg·m-3. Because of their high capacity, clean clothing also effectively minimized transdermal uptake. In addition, ABICAM predicted that contaminated clothing functioned as a vector for transporting DEP and DnBP across indoor microenvironments and reemitted 13-80% (DEP) and 3-27% (DnBP) of the accumulated masses over 48 h. SIGNIFICANCE Though the estimated secondary inhalation exposures from contaminated clothing were low compared to the corresponding primary exposures, these secondary exposures could be accentuated in other contexts, for example, involving longer timeframes of clothing storage, multiple occupants wearing contaminated clothing, and/or repeated instances of clothing-mediated transport of contaminants (e.g., from an occupational setting). IMPACT This modeling study reaffirms the effectiveness of clean clothing in reducing transdermal uptake of airborne SVOCs and conversely, that contaminated clothing could be a source of SVOC exposure via transdermal uptake and by acting as a vector for transporting those contaminants to other locations.
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Affiliation(s)
- Jacob Kvasnicka
- Department of Earth Sciences, University of Toronto, Toronto, Ontario, M5S 3B1, Canada
| | - Elaine A Cohen Hubal
- Center for Public Health and Environmental Assessment, U.S. Environmental Protection Agency, Durham, NC, 27711, USA
| | - Miriam L Diamond
- Department of Earth Sciences, University of Toronto, Toronto, Ontario, M5S 3B1, Canada.
- School of the Environment, University of Toronto, Toronto, Ontario, M5S 3E8, Canada.
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8
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Lakey PSJ, Cummings BE, Waring MS, Morrison GC, Shiraiwa M. Effective mass accommodation for partitioning of organic compounds into surface films with different viscosities. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:1464-1478. [PMID: 37560969 DOI: 10.1039/d3em00213f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Indoor surfaces can act as reservoirs and reaction media influencing the concentrations and type of species that people are exposed to indoors. Mass accommodation and partitioning are impacted by the phase state and viscosity of indoor surface films. We developed the kinetic multi-layer model KM-FILM to simulate organic film formation and growth, but it is computationally expensive to couple such comprehensive models with indoor air box models. Recently, a novel effective mass accommodation coefficient (αeff) was introduced for efficient and effective treatments of gas-particle partitioning. In this study, we extended this approach to a film geometry with αeff as a function of penetration depth into the film, partitioning coefficient, bulk diffusivity, and condensed-phase reaction rate constant. Comparisons between KM-FILM and the αeff method show excellent agreement under most conditions, but with deviations before the establishment of quasi-equilibrium within the penetration depth. We found that the deposition velocity of species and overall film growth are impacted by bulk diffusivity in highly viscous films (Db ∼<10-15 cm2 s-1). Reactions that lead to non-volatile products can increase film thicknesses significantly, with the extent of film growth being dependent on the gas-phase concentration, rate coefficient, partitioning coefficient and diffusivity. Amorphous semisolid films with Db > ∼10-17-10-19 cm2 s-1 can be efficient SVOC reservoirs for compounds with higher partitioning coefficients as they can be released back to the gas phase over extended periods of time, while glassy solid films would not be able to act as reservoirs as gas-film partitioning is impeded.
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Affiliation(s)
- Pascale S J Lakey
- Department of Chemistry, University of California, Irvine, CA 92697, USA.
| | - Bryan E Cummings
- Department of Civil, Architectural and Environmental Engineering, Drexel University, PA 19104, USA
| | - Michael S Waring
- Department of Civil, Architectural and Environmental Engineering, Drexel University, PA 19104, USA
| | - Glenn C Morrison
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC, USA
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, CA 92697, USA.
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9
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Weschler CJ, Nazaroff WW. Ozone Loss: A Surrogate for the Indoor Concentration of Ozone-Derived Products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:13569-13578. [PMID: 37639667 DOI: 10.1021/acs.est.3c03968] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Ozone concentrations tend to be substantially lower indoors than outdoors, largely because of ozone reactions with indoor surfaces. When there are no indoor sources of ozone, a common condition, the net concentration of gaseous products derived from indoor ozone chemistry scales linearly with the difference between outdoor and indoor ozone concentrations, termed "ozone loss." As such, ozone loss is a metric that might be used by epidemiologists to disentangle the adverse health effects of ozone's oxidation products from those of exposure to ozone itself. The present paper examines the characteristics, potential utility, and limitations of the ozone loss concept. We show that for commonly occurring indoor conditions, the ozone loss concentration is directly proportional to the total rate constant for ozone removal on surfaces (ksum) and inversely proportional to the net removal of ozone by air exchange (λ) plus surface reactions (ksum). It follows that the ratio of indoor ozone to ozone loss is equal to the ratio of λ to ksum. Ozone loss is a promising metric for probing potential adverse health effects resulting from exposures to products of indoor ozone chemistry. Notwithstanding its virtues, practitioners using it should be mindful of the limitations discussed in this paper.
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Affiliation(s)
- Charles J Weschler
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey 08854, United States
- International Centre for Indoor Environment and Energy, Technical University of Denmark, Lyngby 2800, Denmark
| | - William W Nazaroff
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720-1710, United States
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10
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Liu J, Zhang R, Xiong J. Machine learning approach for estimating the human-related VOC emissions in a university classroom. BUILDING SIMULATION 2023; 16:915-925. [PMID: 37192916 PMCID: PMC10009360 DOI: 10.1007/s12273-022-0976-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/17/2022] [Accepted: 12/06/2022] [Indexed: 05/18/2023]
Abstract
Indoor air quality becomes increasingly important, partly because the COVID-19 pandemic increases the time people spend indoors. Research into the prediction of indoor volatile organic compounds (VOCs) is traditionally confined to building materials and furniture. Relatively little research focuses on estimation of human-related VOCs, which have been shown to contribute significantly to indoor air quality, especially in densely-occupied environments. This study applies a machine learning approach to accurately estimate the human-related VOC emissions in a university classroom. The time-resolved concentrations of two typical human-related (ozone-related) VOCs in the classroom over a five-day period were analyzed, i.e., 6-methyl-5-hepten-2-one (6-MHO), 4-oxopentanal (4-OPA). By comparing the results for 6-MHO concentration predicted via five machine learning approaches including the random forest regression (RFR), adaptive boosting (Adaboost), gradient boosting regression tree (GBRT), extreme gradient boosting (XGboost), and least squares support vector machine (LSSVM), we find that the LSSVM approach achieves the best performance, by using multi-feature parameters (number of occupants, ozone concentration, temperature, relative humidity) as the input. The LSSVM approach is then used to predict the 4-OPA concentration, with mean absolute percentage error (MAPE) less than 5%, indicating high accuracy. By combining the LSSVM with a kernel density estimation (KDE) method, we further establish an interval prediction model, which can provide uncertainty information and viable option for decision-makers. The machine learning approach in this study can easily incorporate the impact of various factors on VOC emission behaviors, making it especially suitable for concentration prediction and exposure assessment in realistic indoor settings.
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Affiliation(s)
- Jialong Liu
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081 China
| | - Rui Zhang
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081 China
| | - Jianyin Xiong
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081 China
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720 USA
- State Key Laboratory of Green Building in Western China, Xi’an University of Architecture and Technology, Xi’an, 710055 China
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11
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Xu J, Deng H, Wang Y, Li P, Zeng J, Pang H, Xu X, Li X, Yang Y, Gligorovski S. Heterogeneous chemistry of ozone with floor cleaning agent: Implications of secondary VOCs in the indoor environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 862:160867. [PMID: 36521626 DOI: 10.1016/j.scitotenv.2022.160867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Human daily activities such as cooking, and cleaning can affect the indoor air quality by releasing primary emitted volatile organic compounds (VOCs), as well as by the secondary product compounds formed through reactions with ozone (O3) and hydroxyl radicals (OH). However, our knowledge about the formation processes of the secondary VOCs is still incomplete. We performed real-time measurements of primary VOCs released by commercial floor-cleaning detergent and the secondary product compounds formed by heterogeneous reaction of O3 with the constituents of the cleaning agent by use of high-resolution mass spectrometry. We measured the uptake coefficients of O3 on the cleaning detergent at different relative humidities in dark and under different light intensities (320 nm < λ < 400 nm) relevant for the indoor environment. On the basis of the detected compounds we developed tentative reaction mechanisms describing the formation of the secondary VOCs. Intriguingly, under light irradiation the formation of valeraldehyde was observed based on the photosensitized chemistry of acetophenone which is a constituent of the cleaning agent. Finally, we modeled the observed mixing ratios of three aldehydes, glyoxal, methylglyoxal, and 4-oxopentanal with respect to real-life indoor environment. The results suggest that secondary VOCs initiated by ozone chemistry can additionally impact the indoor air pollution.
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Affiliation(s)
- Jinli Xu
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China; Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing, China
| | - Huifan Deng
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China; Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yiqun Wang
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China; Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing, China
| | - Pan Li
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China; Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jianqiang Zeng
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China; Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing, China
| | - Hongwei Pang
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China; Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China
| | - Xin Xu
- Institute of Mass Spectrometry and Atmospheric, Environment, Jinan University, Guangzhou 510632, China
| | - Xue Li
- Institute of Mass Spectrometry and Atmospheric, Environment, Jinan University, Guangzhou 510632, China
| | - Yan Yang
- School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, Guangdong, China; Jieyang Branch of Chemistry and Chemical Engineering Guangdong Laboratory (Rongjiang Laboratory), Jieyang 515200, China; Synergy Innovation Institute of GDUT, Shantou 515041, Guangdong, China.
| | - Sasho Gligorovski
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China; Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China.
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12
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Xu X, Pang H, Liu C, Wang K, Loisel G, Li L, Gligorovski S, Li X. Real-time measurements of product compounds formed through the reaction of ozone with breath exhaled VOCs. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:2237-2248. [PMID: 36472140 DOI: 10.1039/d2em00339b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Human presence can affect indoor air quality because of secondary organic compounds formed upon reactions between gaseous oxidant species, e.g., ozone (O3), hydroxyl radicals (OH), and chemical compounds from skin, exhaled breath, hair and clothes. We assess the gas-phase product compounds generated by reactions of gaseous O3 with volatile organic compounds (VOCs) from exhaled human breath by real time analysis using a high-resolution quadrupole-orbitrap mass spectrometer (HRMS) coupled to a secondary electrospray ionization (SESI) source. Based on the product compounds identified we propose a reaction mechanism initiated by O3 oxidation of the most common breath constituents, isoprene, α-terpinene and ammonia (NH3). The reaction of O3 with isoprene and α-terpinene generates ketones and aldehydes such as 3,4-dihydroxy-2-butanone, methyl vinyl ketone, 3-carbonyl butyraldehyde, formaldehyde and toxic compounds such as 3-methyl furan. Formation of compounds with reduced nitrogen containing functional groups such as amines, imines and imides is highly plausible through NH3 initiated cleavage of the C-O bond. The detected gas-phase product compounds suggest that human breath can additionally affect indoor air quality through the formation of harmful secondary products and future epidemiological studies should evaluate the potential health effects of these compounds.
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Affiliation(s)
- Xin Xu
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China.
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, 510632, China
| | - Hongwei Pang
- State Key Laboratory of Organic Geochemistry, Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
- Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
- Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou, 510640, China
| | - Chao Liu
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China.
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, 510632, China
| | - Kangyi Wang
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China.
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, 510632, China
| | - Gwendal Loisel
- State Key Laboratory of Organic Geochemistry, Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
- Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
- Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou, 510640, China
| | - Lei Li
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China.
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, 510632, China
| | - Sasho Gligorovski
- State Key Laboratory of Organic Geochemistry, Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
- Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China
- Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou, 510640, China
| | - Xue Li
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China.
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, 510632, China
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13
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You B, Zhou W, Li J, Li Z, Sun Y. A review of indoor Gaseous organic compounds and human chemical Exposure: Insights from Real-time measurements. ENVIRONMENT INTERNATIONAL 2022; 170:107611. [PMID: 36335895 DOI: 10.1016/j.envint.2022.107611] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 10/29/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
Gaseous organic compounds, mainly volatile organic compounds (VOCs), have become a wide concern in various indoor environments where we spend the majority of our daily time. The sources, compositions, variations, and sinks of indoor VOCs are extremely complex, and their potential impacts on human health are less understood. Owing to the deployment of the state-of-the-art real-time mass spectrometry during the last two decades, our understanding of the sources, dynamic changes and chemical transformations of VOCs indoors has been significantly improved. This review aims to summarize the key findings from mass spectrometry measurements in recent indoor studies including residence, classroom, office, sports center, etc. The sources and sinks, compositions and distributions of indoor VOCs, and the factors (e.g., human activities, air exchange rate, temperature and humidity) driving the changes in indoor VOCs are discussed. The physical and chemical processes of gas-particle partitioning and secondary oxidation processes of VOCs, and their impacts on human health are summarized. Finally, the recommendations for future research directions on indoor VOCs measurements and indoor chemistry are proposed.
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Affiliation(s)
- Bo You
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Zhou
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
| | - Junyao Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhijie Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yele Sun
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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14
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Deng H, Xu X, Wang K, Xu J, Loisel G, Wang Y, Pang H, Li P, Mai Z, Yan S, Li X, Gligorovski S. The Effect of Human Occupancy on Indoor Air Quality through Real-Time Measurements of Key Pollutants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15377-15388. [PMID: 36279129 DOI: 10.1021/acs.est.2c04609] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The primarily emitted compounds by human presence, e.g., skin and volatile organic compounds (VOCs) in breath, can react with typical indoor air oxidants, ozone (O3), and hydroxyl radicals (OH), leading to secondary organic compounds. Nevertheless, our understanding about the formation processes of the compounds through reactions of indoor air oxidants with primary emitted pollutants is still incomplete. In this study we performed real-time measurements of nitrous acid (HONO), nitrogen oxides (NOx = NO + NO2), O3, and VOCs to investigate the contribution of human presence and human activity, e.g., mopping the floor, to secondary organic compounds. During human occupancy a significant increase was observed of 1-butene, isoprene, and d-limonene exhaled by the four adults in the room and an increase of methyl vinyl ketone/methacrolein, methylglyoxal, and 3-methylfuran, formed as secondary compounds through reactions of OH radicals with isoprene. Intriguingly, the level of some compounds (e.g., m/z 126, 6-methyl-5-hepten-2-one, m/z 152, dihydrocarvone, and m/z 194, geranyl acetone) formed through reactions of O3 with the primary compounds was higher in the presence of four adults than during the period of mopping the floor with commercial detergent. These results indicate that human presence can additionally degrade the indoor air quality.
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Affiliation(s)
- Huifan Deng
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640, China
- University of Chinese Academy of Sciences, Beijing100864, China
| | - Xin Xu
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou510632, China
| | - Kangyi Wang
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou510632, China
| | - Jinli Xu
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640, China
- University of Chinese Academy of Sciences, Beijing100864, China
| | - Gwendal Loisel
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640, China
| | - Yiqun Wang
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640, China
- University of Chinese Academy of Sciences, Beijing100864, China
| | - Hongwei Pang
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640, China
| | - Pan Li
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640, China
- University of Chinese Academy of Sciences, Beijing100864, China
| | - Zebin Mai
- Guangzhou Hexin Instrument Co., Ltd., Guangzhou510530, China
| | - Shichao Yan
- Guangzhou Hexin Instrument Co., Ltd., Guangzhou510530, China
| | - Xue Li
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou510632, China
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou510632, China
| | - Sasho Gligorovski
- State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou510640, China
- Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou510640, China
- Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou510640, China
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15
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He J, Yin Y, Pei J, Sun Y, Liu Z, Chen Q, Yang X. A model to evaluate ozone distribution and reaction byproducts in aircraft cabin environments. INDOOR AIR 2022; 32:e13178. [PMID: 36437656 DOI: 10.1111/ina.13178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 11/08/2022] [Accepted: 11/09/2022] [Indexed: 06/16/2023]
Abstract
Ozone and byproducts of ozone-initiated reactions are among the primary pollutants in aircraft cabins. However, investigations of the spatial distribution and reaction mechanisms of these pollutants are insufficient. This study established a computational fluid dynamics-based model to evaluate ozone and byproduct distribution, considering ozone reactions in air, adsorption onto surfaces, and byproduct desorption from surfaces. The model was implemented in an authentic single-aisle aircraft cabin and validated by measurements recorded during the aircraft cruise phase. Ozone concentrations in the supply air-dominated area were approximately 50% higher than that in the passenger breathing zone, suggesting that human surfaces represent a significant ozone sink. The deposition velocity onto human bodies was 21.83 m/h, surpassing 3.97 m/h on other cabin interior surface areas. Our model provides a mechanistic tool to analyze ozone and byproduct concentration distributions, which would be useful for assessing passenger health risks and for developing strategies for healthier aircraft cabin environments.
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Affiliation(s)
- Junzhou He
- Department of Power Engineering, North China Electric Power University, Baoding, Hebei, People's Republic of China
- Department of Building Science, Tsinghua University, Beijing, China
| | - Yihui Yin
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Jingjing Pei
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Yuexia Sun
- Tianjin Key Laboratory of Indoor Air Environmental Quality Control, School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Zhijian Liu
- Department of Power Engineering, North China Electric Power University, Baoding, Hebei, People's Republic of China
| | - Qingyan Chen
- Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Xudong Yang
- Department of Building Science, Tsinghua University, Beijing, China
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16
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Wang H, Xiong J, Wei W. Measurement methods and impact factors for the key parameters of VOC/SVOC emissions from materials in indoor and vehicular environments: A review. ENVIRONMENT INTERNATIONAL 2022; 168:107451. [PMID: 35963058 DOI: 10.1016/j.envint.2022.107451] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/30/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
The emissions of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) from indoor building and vehicle cabin materials can adversely affect human health. Many mechanistic models to predict the VOC/SVOC emission characteristics have been proposed. Nowadays, the main obstacle to accurate model prediction is the availability and reliability of the physical parameters used in the model, such as the initial emittable concentration, the diffusion coefficient, the partition coefficient, and the gas-phase SVOC concentration adjacent to the material surface. The purpose of this work is to review the existing methods for measuring the key parameters of VOCs/SVOCs from materials in both indoor and vehicular environments. The pros and cons of these methods are analyzed, and the available datasets found in the literature are summarized. Some methods can determine one single key parameter, while other methods can determine two or three key parameters simultaneously. The impacts of multiple factors (temperature, relative humidity, loading ratio, and air change rate) on VOC/SVOC emission behaviors are discussed. The existing measurement methods span very large spatial and time scales: the spatial scale varies from micro to macro dimensions; and the time scale in chamber tests varies from several hours to one month for VOCs, and may even span years for SVOCs. Based on the key parameters, a pre-assessment approach for indoor and vehicular air quality is introduced in this review. The approach uses the key parameters for different material combinations to pre-assess the VOC/SVOC concentrations or human exposure levels during the design stage of buildings or vehicles, which can assist designers to select appropriate materials and achieve effective source control.
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Affiliation(s)
- Haimei Wang
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Jianyin Xiong
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Wenjuan Wei
- University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Observatory (OOAI), 77447 Champs-sur-Marne, France
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17
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Morrison G, Eftekhari A, Fan A, Majluf F, Krechmer JE. The influence of personal care products on ozone-skin surface chemistry. PLoS One 2022; 17:e0268263. [PMID: 36174009 PMCID: PMC9522313 DOI: 10.1371/journal.pone.0268263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/25/2022] [Indexed: 11/19/2022] Open
Abstract
Personal care products are increasingly being marketed to protect skin from the potentially harmful effects of air pollution. Here, we experimentally measure ozone deposition rates to skin and the generation rates and yields of oxidized products from bare skin and skin coated with various lotion formulations. Lotions reduced the ozone flux to the skin surface by 12% to 25%; this may be due to dilution of reactive skin lipids with inert lotion compounds or by reducing ozone diffusivity within the resulting mixture. The yields of volatile squalene oxidation products were 25% to 70% lower for a commercial sunscreen and for a base lotion with an added polymer or with antioxidants. Lower yields are likely due to competitive reactions of ozone with lotion ingredients including some ingredients that are not intended to be ozone sinks. The dynamics of the emissions of squalene ozonation product 6 methyl-2-heptenone (6MHO) suggest that lotions can dramatically reduce the solubility of products in the skin film. While some lotions appear to reduce the rate of oxidation of squalene by ozone, this evidence does not yet demonstrate that the lotions reduce the impact of air pollution on skin health.
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Affiliation(s)
- Glenn Morrison
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * E-mail:
| | - Azin Eftekhari
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Aixing Fan
- Colgate-Palmolive Co., Piscataway, NJ, United States of America
| | - Francesca Majluf
- Aerodyne Research Inc., Billerica, Massachusetts, United States of America
| | - Jordan E. Krechmer
- Aerodyne Research Inc., Billerica, Massachusetts, United States of America
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18
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Zannoni N, Lakey PSJ, Won Y, Shiraiwa M, Rim D, Weschler CJ, Wang N, Ernle L, Li M, Bekö G, Wargocki P, Williams J. The human oxidation field. Science 2022; 377:1071-1077. [PMID: 36048928 DOI: 10.1126/science.abn0340] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hydroxyl (OH) radicals are highly reactive species that can oxidize most pollutant gases. In this study, high concentrations of OH radicals were found when people were exposed to ozone in a climate-controlled chamber. OH concentrations calculated by two methods using measurements of total OH reactivity, speciated alkenes, and oxidation products were consistent with those obtained from a chemically explicit model. Key to establishing this human-induced oxidation field is 6-methyl-5-hepten-2-one (6-MHO), which forms when ozone reacts with the skin-oil squalene and subsequently generates OH efficiently through gas-phase reaction with ozone. A dynamic model was used to show the spatial extent of the human-generated OH oxidation field and its dependency on ozone influx through ventilation. This finding has implications for the oxidation, lifetime, and perception of chemicals indoors and, ultimately, human health.
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Affiliation(s)
- Nora Zannoni
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | | | - Youngbo Won
- Department of Architectural Engineering, Pennsylvania State University, University Park, PA, USA
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, CA, USA
| | - Donghyun Rim
- Department of Architectural Engineering, Pennsylvania State University, University Park, PA, USA
| | - Charles J Weschler
- International Centre for Indoor Environment and Energy, Environmental and Resource Engineering, DTU Sustain, Technical University of Denmark, Lyngby, Denmark.,Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ, USA
| | - Nijing Wang
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Lisa Ernle
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Mengze Li
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
| | - Gabriel Bekö
- International Centre for Indoor Environment and Energy, Environmental and Resource Engineering, DTU Sustain, Technical University of Denmark, Lyngby, Denmark
| | - Pawel Wargocki
- International Centre for Indoor Environment and Energy, Environmental and Resource Engineering, DTU Sustain, Technical University of Denmark, Lyngby, Denmark
| | - Jonathan Williams
- Atmospheric Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany.,Energy, Environment and Water Research Center, The Cyprus Institute, Nicosia, Cyprus
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19
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Coffaro B, Weisel CP. Reactions and Products of Squalene and Ozone: A Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7396-7411. [PMID: 35648815 PMCID: PMC9231367 DOI: 10.1021/acs.est.1c07611] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 05/13/2022] [Accepted: 05/13/2022] [Indexed: 05/15/2023]
Abstract
This critical review describes the squalene-ozone (SqOz) reaction, or squalene ozonolysis. Ambient ozone penetrates indoors and drives indoor air chemistry. Squalene, a component of human skin oil, contains six carbon-carbon double bonds and is very reactive with ozone. Bioeffluents from people contribute to indoor air chemistry and affect the indoor air quality, resulting in exposures because people spend the majority of their time indoors. The SqOz reaction proceeds through various formation pathways and produces compounds that include aldehydes, ketones, carboxylic acids, and dicarbonyl species, which have a range of volatilities. In this critical review of SqOz chemistry, information on the mechanism of reaction, reaction probability, rate constants, and reaction kinetics are compiled. Characterizations of SqOz reaction products have been done in laboratory experiments and real-world settings. The effect of multiple environmental parameters (ozone concentration, air exchange rate (AER), temperature, and relative humidity (RH)) in indoor settings are summarized. This critical review concludes by identifying the paucity of available exposure, health, and toxicological data for known reaction products. Key knowledge gaps about SqOz reactions leading to indoor exposures and adverse health outcomes are provided as well as an outlook on where the field is headed.
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Affiliation(s)
- Breann Coffaro
- Environmental
and Health Sciences Institute and Graduate Program in Exposure Science, Rutgers, The State University of New Jersey, Piscataway Township, New
Jersey 08854, United
States
| | - Clifford P. Weisel
- Environmental
and Health Sciences Institute and School of Public Health, Rutgers, The State University of New Jersey, Piscataway Township, New
Jersey 08854, United
States
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20
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Zhou Z, Lakey PSJ, von Domaros M, Wise N, Tobias DJ, Shiraiwa M, Abbatt JPD. Multiphase Ozonolysis of Oleic Acid-Based Lipids: Quantitation of Major Products and Kinetic Multilayer Modeling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:7716-7728. [PMID: 35671499 DOI: 10.1021/acs.est.2c01163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Commonly found in atmospheric aerosols, cooking oils, and human sebum, unsaturated lipids rapidly decay upon exposure to ozone, following the Criegee mechanism. Here, the gas-surface ozonolysis of three oleic acid-based compounds was studied in a reactor and indoors. Under dry conditions, quantitative product analyses by 1H NMR indicate up to 79% molar yield of stable secondary ozonides (SOZs) in oxidized triolein and methyl oleate coatings. Elevated relative humidity (RH) significantly suppresses the SOZ yields, enhancing the formation of condensed-phase aldehydes and volatile C9 products. Along with kinetic parameters informed by molecular dynamics simulations, these results were used as constraints in a kinetic multilayer model (KM-GAP) simulating triolein ozonolysis. Covering a wide range of coating thicknesses and ozone levels, the model predicts a much faster decay near the gas-lipid interface compared to the bulk. Although the dependence of RH on SOZ yields is well predicted, the model overestimates the production of H2O2 and aldehydes. With negligible dependence on RH, the product composition for oxidized oleic acid is substantially affected by a competitive reaction between Criegee intermediates (CIs) and carboxylic acids. The resulting α-acyloxyalkyl hydroperoxides (α-AAHPs) have much higher molar yields (29-38%) than SOZs (12-16%). Overall, the ozone-lipid chemistry could affect the indoor environment through "crust" accumulation on surfaces and volatile organic compound (VOC) emission. In the atmosphere, the peroxide formation and changes in particle hygroscopicity may have effects on climate. The related health impacts are also discussed.
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Affiliation(s)
- Zilin Zhou
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
| | - Pascale S J Lakey
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Michael von Domaros
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Natsuko Wise
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Douglas J Tobias
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
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21
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Salthammer T, Morrison GC. Temperature and indoor environments. INDOOR AIR 2022; 32:e13022. [PMID: 35622714 DOI: 10.1111/ina.13022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 02/20/2022] [Accepted: 03/13/2022] [Indexed: 06/15/2023]
Abstract
From the thermodynamic perspective, the term temperature is clearly defined for ideal physical systems: A unique temperature can be assigned to each black body via its radiation spectrum, and the temperature of an ideal gas is given by the velocity distribution of the molecules. While the indoor environment is not an ideal system, fundamental physical and chemical processes, such as diffusion, partitioning equilibria, and chemical reactions, are predictably temperature-dependent. For example, the logarithm of reaction rate and equilibria constants are proportional to the reciprocal of the absolute temperature. It is therefore possible to have non-linear, very steep changes in chemical phenomena over a relatively small temperature range. On the contrary, transport processes are more influenced by spatial temperature, momentum, and pressure gradients as well as by the density, porosity, and composition of indoor materials. Consequently, emergent phenomena, such as emission rates or dynamic air concentrations, can be the result of complex temperature-dependent relationships that require a more empirical approach. Indoor environmental conditions are further influenced by the thermal comfort needs of occupants. Not only do occupants have to create thermal conditions that serve to maintain their core body temperature, which is usually accomplished by wearing appropriate clothing, but also the surroundings must be adapted so that they feel comfortable. This includes the interaction of the living space with the ambient environment, which can vary greatly by region and season. Design of houses, apartments, commercial buildings, and schools is generally utility and comfort driven, requiring an appropriate energy balance, sometimes considering ventilation but rarely including the impact of temperature on indoor contaminant levels. In our article, we start with a review of fundamental thermodynamic variables and discuss their influence on typical indoor processes. Then, we describe the heat balance of people in their thermal environment. An extensive literature study is devoted to the thermal conditions in buildings, the temperature-dependent release of indoor pollutants from materials and their distribution in the various interior compartments as well as aspects of indoor chemistry. Finally, we assess the need to consider temperature holistically with regard to the changes to be expected as a result of global emergencies such as climate change.
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Affiliation(s)
- Tunga Salthammer
- Department of Material Analysis and Indoor Chemistry, Fraunhofer WKI, Braunschweig, Germany
| | - Glenn C Morrison
- Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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22
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Zhang M, Gao Y, Xiong J. Characterization of the off-body squalene ozonolysis on indoor surfaces. CHEMOSPHERE 2022; 291:132772. [PMID: 34742760 DOI: 10.1016/j.chemosphere.2021.132772] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/09/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
Chemical reaction and physical transport characteristics of indoor surfaces play an important role in indoor air quality. This study presents a kinetic model to describe the reaction of ozone with squalene on indoor surfaces in a family house, by incorporating external and internal mass transfer, surface partitioning, and chemical reaction on indoor surfaces. Field experiments were performed in the family house. The first 3-days of data, collected when the house was unoccupied, are used to derive the key parameters in the model, which are then used for predicting the concentrations in other unoccupied days. Comparison of squalene oxidation products during the occupied and unoccupied periods shows that even if the house is unoccupied for several days, the indoor concentrations of 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA) remain substantial, demonstrating that surface reaction of ozone with off-body squalene can significantly impact the composition of indoor air. Model predictions of the three compounds (ozone, 6-MHO, and 4-OPA) agree well with the experimental observations for all test days. Furthermore, we make the first attempt to estimate the duration of typical polyunsaturated aldehydes (TOP, TOT, and TTT), which indicated that these compounds, as well as off-body squalene, can persist on indoor surfaces for a relatively long period in the examined residence.
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Affiliation(s)
- Meixia Zhang
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Ying Gao
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China
| | - Jianyin Xiong
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing, 100081, China; Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, 94720, United States.
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23
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Nazaroff WW, Weschler CJ. Indoor ozone: Concentrations and influencing factors. INDOOR AIR 2022; 32:e12942. [PMID: 34609012 DOI: 10.1111/ina.12942] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 05/03/2023]
Abstract
Because people spend most of their time indoors, much of their exposure to ozone occurs in buildings, which are partially protective against outdoor ozone. Measurements in approximately 2000 indoor environments (residences, schools, and offices) show a central tendency for average indoor ozone concentration of 4-6 ppb and an indoor to outdoor concentration ratio of about 25%. Considerable variability in this ratio exists among buildings, as influenced by seven building-associated factors: ozone removal in mechanical ventilation systems, ozone penetration through the building envelope, air-change rates, ozone loss rate on fixed indoor surfaces, ozone loss rate on human occupants, ozone loss by homogeneous reaction with nitrogen oxides, and ozone loss by reaction with gas-phase organics. Among these, the most important are air-change rates, ozone loss rate on fixed indoor surfaces, and, in densely occupied spaces, ozone loss rate on human occupants. Although most indoor ozone originates outdoors and enters with ventilation air, indoor emission sources can materially increase indoor ozone concentrations. Mitigation technologies to reduce indoor ozone concentrations are available or are being investigated. The most mature of these technologies, activated carbon filtration of mechanical ventilation supply air, shows a high modeled health-benefit to cost ratio when applied in densely occupied spaces.
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Affiliation(s)
- William W Nazaroff
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA, USA
| | - Charles J Weschler
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ, USA
- International Centre for Indoor Environment and Energy, Technical University of Denmark, Lyngby, Denmark
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24
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Wu T, Tasoglou A, Huber H, Stevens PS, Boor BE. Influence of Mechanical Ventilation Systems and Human Occupancy on Time-Resolved Source Rates of Volatile Skin Oil Ozonolysis Products in a LEED-Certified Office Building. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:16477-16488. [PMID: 34851619 DOI: 10.1021/acs.est.1c03112] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Building mechanical ventilation systems are a major driver of indoor air chemistry as their design and operation influences indoor ozone (O3) concentrations, the dilution and transport of indoor-generated volatile organic compounds (VOCs), and indoor environmental conditions. Real-time VOC and O3 measurements were integrated with a building sensing platform to evaluate the influence of mechanical ventilation modes and human occupancy on the dynamics of skin oil ozonolysis products (SOOPs) in an office in a LEED-certified building during the winter. The ventilation system operated under variable recirculation ratios (RRs) from RR = 0 (100% outdoor air) to RR = 1 (100% recirculation air). Time-resolved source rates for 6-methyl-5-hepten-2-one (6-MHO), 4-oxopentanal (4-OPA), and decanal were highly dynamic and changed throughout the day with RR and occupancy. Total SOOP source rates during high-occupancy periods (10:00-18:00) varied from 2500-3000 μg h-1 when RR = 0.1 to 6300-6700 μg h-1 when RR = 1. Source rates for gas-phase reactions, outdoor air, and occupant-associated emissions generally decreased with increasing RR. The recirculation air source rate increased with RR and typically became the dominant source for RR > 0.5. SOOP emissions from surface reservoirs were also a prominent source, contributing 10-50% to total source rates. Elevated per person SOOP emission factors were observed, potentially due to multiple layers of soiled clothing worn during winter.
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Affiliation(s)
- Tianren Wu
- Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Ray W. Herrick Laboratories, Center for High Performance Buildings, Purdue University, West Lafayette, Indiana 47907, United States
| | - Antonios Tasoglou
- RJ Lee Group Incorporated, Monroeville, Pennsylvania 15146, United States
| | - Heinz Huber
- Edelweiss Technology Solutions, Limited Liability Company, Novelty, Ohio 44072, United States
| | - Philip S Stevens
- O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, United States
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Brandon E Boor
- Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, United States
- Ray W. Herrick Laboratories, Center for High Performance Buildings, Purdue University, West Lafayette, Indiana 47907, United States
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25
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Lakey PSJ, Eichler CMA, Wang C, Little JC, Shiraiwa M. Kinetic multi-layer model of film formation, growth, and chemistry (KM-FILM): Boundary layer processes, multi-layer adsorption, bulk diffusion, and heterogeneous reactions. INDOOR AIR 2021; 31:2070-2083. [PMID: 33991124 DOI: 10.1111/ina.12854] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/15/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
Large surface area-to-volume ratios indoors cause heterogeneous interactions to be especially important. Semi-volatile organic compounds can deposit on impermeable indoor surfaces forming thin organic films. We developed a new model to simulate the initial film formation by treating gas-phase diffusion and turbulence through a surface boundary layer and multi-layer reversible adsorption on rough surfaces, as well as subsequent film growth by resolving bulk diffusion and chemical reactions in a film. The model was applied with consistent parameters to reproduce twenty-one sets of film formation measurements due to multi-layer adsorption of multiple phthalates onto different indoor-relevant surfaces, showing that the films should initially be patchy with the formation of pyramid-like structures on the surface. Sensitivity tests showed that highly turbulent conditions can lead to the film growing by more than a factor of two compared to low turbulence conditions. If surface films adopt an ultra-viscous state with bulk diffusion coefficients of less than 10-18 cm2 s-1 , a significant decrease in film growth is expected. The presence of chemical reactions in the film has the potential to increase the rate of film growth by nearly a factor of two.
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Affiliation(s)
| | - Clara M A Eichler
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Chunyi Wang
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
| | - John C Little
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, USA
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, CA, USA
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26
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Zannoni N, Li M, Wang N, Ernle L, Bekö G, Wargocki P, Langer S, Weschler CJ, Morrison G, Williams J. Effect of Ozone, Clothing, Temperature, and Humidity on the Total OH Reactivity Emitted from Humans. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13614-13624. [PMID: 34591444 PMCID: PMC8529706 DOI: 10.1021/acs.est.1c01831] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 06/01/2023]
Abstract
People influence indoor air chemistry through their chemical emissions via breath and skin. Previous studies showed that direct measurement of total OH reactivity of human emissions matched that calculated from parallel measurements of volatile organic compounds (VOCs) from breath, skin, and the whole body. In this study, we determined, with direct measurements from two independent groups of four adult volunteers, the effect of indoor temperature and humidity, clothing coverage (amount of exposed skin), and indoor ozone concentration on the total OH reactivity of gaseous human emissions. The results show that the measured concentrations of VOCs and ammonia adequately account for the measured total OH reactivity. The total OH reactivity of human emissions was primarily affected by ozone reactions with organic skin-oil constituents and increased with exposed skin surface, higher temperature, and higher humidity. Humans emitted a comparable total mixing ratio of VOCs and ammonia at elevated temperature-low humidity and elevated temperature-high humidity, with relatively low diversity in chemical classes. In contrast, the total OH reactivity increased with higher temperature and higher humidity, with a larger diversity in chemical classes compared to the total mixing ratio. Ozone present, carbonyl compounds were the dominant reactive compounds in all of the reported conditions.
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Affiliation(s)
- Nora Zannoni
- Atmospheric
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Mengze Li
- Atmospheric
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Nijing Wang
- Atmospheric
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Lisa Ernle
- Atmospheric
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
| | - Gabriel Bekö
- International
Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Pawel Wargocki
- International
Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Sarka Langer
- IVL
Swedish Environmental Research Institute, 41133 Göteborg, Sweden
- Division
of Building Services Engineering, Department of Architecture and Civil
Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden
| | - Charles J. Weschler
- International
Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, 2800 Lyngby, Denmark
- Environmental
and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Glenn Morrison
- Department
of Environmental Sciences and Engineering, Gillings School of Global
Public Health, The University of North Carolina
at Chapel Hill, Chapel
Hill, North Carolina 27599-7431, United States
| | - Jonathan Williams
- Atmospheric
Chemistry Department, Max Planck Institute
for Chemistry, 55128 Mainz, Germany
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27
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Finewax Z, Pagonis D, Claflin MS, Handschy AV, Brown WL, Jenks O, Nault BA, Day DA, Lerner BM, Jimenez JL, Ziemann PJ, de Gouw JA. Quantification and source characterization of volatile organic compounds from exercising and application of chlorine-based cleaning products in a university athletic center. INDOOR AIR 2021; 31:1323-1339. [PMID: 33337567 DOI: 10.1111/ina.12781] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/30/2020] [Indexed: 05/15/2023]
Abstract
Humans spend approximately 90% of their time indoors, impacting their own air quality through occupancy and activities. Human VOC emissions indoors from exercise are still relatively uncertain, and questions remain about emissions from chlorine-based cleaners. To investigate these and other issues, the ATHLETic center study of Indoor Chemistry (ATHLETIC) campaign was conducted in the weight room of the Dal Ward Athletic Center at the University of Colorado Boulder. Using a Vocus Proton-Transfer-Reaction Time-of-Flight Mass Spectrometer (Vocus PTR-TOF), an Aerodyne Gas Chromatograph (GC), an Iodide-Chemical Ionization Time-of-Flight Mass Spectrometer (I-CIMS), and Picarro cavity ringdown spectrometers, we alternated measurements between the weight room and supply air, allowing for determination of VOC, NH3 , H2 O, and CO2 emission rates per person (emission factors). Human-derived emission factors were higher than previous studies of measuring indoor air quality in rooms with individuals at rest and correlated with increased CO2 emission factors. Emission factors from personal care products (PCPs) were consistent with previous studies and typically decreased throughout the day. In addition, N-chloraldimines were observed in the gas phase after the exercise equipment was cleaned with a dichlor solution. The chloraldimines likely originated from reactions of free amino acids with HOCl on gym surfaces.
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Affiliation(s)
- Zachary Finewax
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Demetrios Pagonis
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | | | - Anne V Handschy
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Wyatt L Brown
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Olivia Jenks
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Benjamin A Nault
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Douglas A Day
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | | | - Jose L Jimenez
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Paul J Ziemann
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
| | - Joost A de Gouw
- Cooperative Institute for Research in Environmental Sciences (CIRES, University of Colorado, Boulder, CO, USA
- Department of Chemistry, University of Colorado, Boulder, CO, USA
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28
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von Domaros M, Liu Y, Butman JL, Perlt E, Geiger FM, Tobias DJ. Molecular Orientation at the Squalene/Air Interface from Sum Frequency Generation Spectroscopy and Atomistic Modeling. J Phys Chem B 2021; 125:3932-3941. [DOI: 10.1021/acs.jpcb.0c11158] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael von Domaros
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Yangdongling Liu
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Jana L. Butman
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Eva Perlt
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
| | - Franz M. Geiger
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Douglas J. Tobias
- Department of Chemistry, University of California Irvine, Irvine, California 92697, United States
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29
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Zhang M, Xiong J, Liu Y, Misztal PK, Goldstein AH. Physical-Chemical Coupling Model for Characterizing the Reaction of Ozone with Squalene in Realistic Indoor Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:1690-1698. [PMID: 33464056 DOI: 10.1021/acs.est.0c06216] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Squalene can react with indoor ozone to generate a series of volatile and semi-volatile organic compounds, some of which may be skin or respiratory irritants, causing adverse health effects. Better understanding of the ozone/squalene reaction and product transport characteristics is thus important. In this study, we developed a physical-chemical coupling model to describe the behavior of ozone/squalene reaction products, that is, 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA) in the gas phase and skin, by considering the chemical reaction and physical transport processes (external convection, internal diffusion, and surface uptake). Experiments without intervention were performed in a single-family house in California utilizing time- and space-resolved measurements. The key parameters in the model were extracted from 5 day data and then used to predict the behaviors in some other days. Predictions from the present model can reproduce the concentration profiles of the three compounds (ozone, 6-MHO, and 4-OPA) well (R2 = 0.82-0.89), indicating high accuracy of the model. Exposure analysis shows that the total amount of 6-MHO and 4-OPA entering the blood capillaries in 4 days can reach 14.6 and 30.1 μg, respectively. The contribution of different sinks to ozone removal in the tested realistic indoor environment was also analyzed.
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Affiliation(s)
- Meixia Zhang
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Jianyin Xiong
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720, United States
| | - Yingjun Liu
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720, United States
- BIC-ESAT and SKL-ESPC, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Pawel K Misztal
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720, United States
- Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, Texas 78712, United States
| | - Allen H Goldstein
- Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720, United States
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
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30
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Morrison GC, Eftekhari A, Majluf F, Krechmer JE. Yields and Variability of Ozone Reaction Products from Human Skin. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:179-187. [PMID: 33337871 DOI: 10.1021/acs.est.0c05262] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The skin of 20 human participants was exposed to ∼110 ppb O3 and volatile products of the resulting chemistry were quantified in real time. Yields (ppb product emitted/ppb ozone consumed) for 40 products were quantified. Major products of the primary reaction of ozone-squalene included 6-methyl 5-hepten-2-one (6-MHO) and geranyl acetone (GA) with average yields of 0.22 and 0.16, respectively. Other major products included decanal, methacrolein (or methyl vinyl ketone), nonanal, and butanal. Yields varied widely among participants; summed yields ranged from 0.33 to 0.93. The dynamic increase in emission rates during ozone exposure also varied among participants, possibly indicative of differences in the thickness of the skin lipid layer. Factor analysis indicates that much of the variability among participants is due to factors associated with the relative abundance of (1) "fresh" skin lipid constituents (such as squalene and fatty acids), (2) oxidized skin lipids, and (3) exogenous compounds. This last factor appears to be associated with the presence of oleic and linoleic acids and could be accounted for by uptake of cooking oils or personal care products to skin lipids.
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Affiliation(s)
- Glenn C Morrison
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Azin Eftekhari
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Francesca Majluf
- Aerodyne Research Inc., Billerica, Massachusetts 01821, United States
| | - Jordan E Krechmer
- Aerodyne Research Inc., Billerica, Massachusetts 01821, United States
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31
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Eichler CMA, Hubal EAC, Xu Y, Cao J, Bi C, Weschler CJ, Salthammer T, Morrison GC, Koivisto AJ, Zhang Y, Mandin C, Wei W, Blondeau P, Poppendieck D, Liu X, Delmaar CJE, Fantke P, Jolliet O, Shin HM, Diamond ML, Shiraiwa M, Zuend A, Hopke PK, von Goetz N, Kulmala M, Little JC. Assessing Human Exposure to SVOCs in Materials, Products, and Articles: A Modular Mechanistic Framework. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:25-43. [PMID: 33319994 PMCID: PMC7877794 DOI: 10.1021/acs.est.0c02329] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A critical review of the current state of knowledge of chemical emissions from indoor sources, partitioning among indoor compartments, and the ensuing indoor exposure leads to a proposal for a modular mechanistic framework for predicting human exposure to semivolatile organic compounds (SVOCs). Mechanistically consistent source emission categories include solid, soft, frequent contact, applied, sprayed, and high temperature sources. Environmental compartments are the gas phase, airborne particles, settled dust, indoor surfaces, and clothing. Identified research needs are the development of dynamic emission models for several of the source emission categories and of estimation strategies for critical model parameters. The modular structure of the framework facilitates subsequent inclusion of new knowledge, other chemical classes of indoor pollutants, and additional mechanistic processes relevant to human exposure indoors. The framework may serve as the foundation for developing an open-source community model to better support collaborative research and improve access for application by stakeholders. Combining exposure estimates derived using this framework with toxicity data for different end points and toxicokinetic mechanisms will accelerate chemical risk prioritization, advance effective chemical management decisions, and protect public health.
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Affiliation(s)
- Clara M A Eichler
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Elaine A Cohen Hubal
- Office of Research and Development, U.S. EPA, Research Triangle Park, North Carolina 27711, United States
| | - Ying Xu
- Department of Building Science, Tsinghua University, Beijing 100084, China
| | - Jianping Cao
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, Guangdong 510006, China
| | - Chenyang Bi
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
| | - Charles J Weschler
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey 08854, United States
- International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Lyngby 2800, Denmark
| | - Tunga Salthammer
- Fraunhofer WKI, Department of Material Analysis and Indoor Chemistry, Braunschweig 38108, Germany
| | - Glenn C Morrison
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Antti Joonas Koivisto
- Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Helsinki 00014, Finland
| | - Yinping Zhang
- Department of Building Science, Tsinghua University, Beijing 100084, China
| | - Corinne Mandin
- University of Paris-Est, Scientific and Technical Center for Building (CSTB), French Indoor Air Quality Observatory (OQAI), Champs sur Marne 77447, France
| | - Wenjuan Wei
- University of Paris-Est, Scientific and Technical Center for Building (CSTB), French Indoor Air Quality Observatory (OQAI), Champs sur Marne 77447, France
| | - Patrice Blondeau
- Laboratoire des Sciences de l'Ingénieur pour l'Environnement - LaSIE, Université de La Rochelle, La Rochelle 77447, France
| | - Dustin Poppendieck
- Engineering Lab, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Xiaoyu Liu
- Office of Research and Development, U.S. EPA, Research Triangle Park, North Carolina 27711, United States
| | - Christiaan J E Delmaar
- National Institute for Public Health and the Environment, Center for Safety of Substances and Products, Bilthoven 3720, The Netherlands
| | - Peter Fantke
- Quantitative Sustainability Assessment, Department of Technology, Management and Economics, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Olivier Jolliet
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Hyeong-Moo Shin
- Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Miriam L Diamond
- Department of Earth Sciences, University of Toronto, Toronto, Ontario M5S 3B1, Canada
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Andreas Zuend
- Department of Atmospheric and Oceanic Sciences, McGill University, Montreal, Quebec H3A0B9, Canada
| | - Philip K Hopke
- Center for Air Resources Engineering and Science, Clarkson University, Potsdam, New York 13699-5708, United States
- Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, United States
| | | | - Markku Kulmala
- Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Helsinki 00014, Finland
| | - John C Little
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
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32
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Ault AP, Grassian VH, Carslaw N, Collins DB, Destaillats H, Donaldson DJ, Farmer DK, Jimenez JL, McNeill VF, Morrison GC, O'Brien RE, Shiraiwa M, Vance ME, Wells JR, Xiong W. Indoor Surface Chemistry: Developing a Molecular Picture of Reactions on Indoor Interfaces. Chem 2020; 6:3203-3218. [PMID: 32984643 PMCID: PMC7501779 DOI: 10.1016/j.chempr.2020.08.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chemical reactions on indoor surfaces play an important role in air quality in indoor environments, where humans spend 90% of their time. We focus on the challenges of understanding the complex chemistry that takes place on indoor surfaces and identify crucial steps necessary to gain a molecular-level understanding of environmental indoor surface chemistry: (1) elucidate key surface reaction mechanisms and kinetics important to indoor air chemistry, (2) define a range of relevant and representative surfaces to probe, and (3) define the drivers of surface reactivity, particularly with respect to the surface composition, light, and temperature. Within the drivers of surface composition are the roles of adsorbed/absorbed water associated with indoor surfaces and the prevalence, inhomogeneity, and properties of secondary organic films that can impact surface reactivity. By combining laboratory studies, field measurements, and modeling we can gain insights into the molecular processes necessary to further our understanding of the indoor environment.
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Affiliation(s)
- Andrew P Ault
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vicki H Grassian
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.,Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037, USA.,Department of Nanoengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nicola Carslaw
- Department of Environment and Geography, University of York, York, North Yorkshire YO10 5NG, UK
| | - Douglas B Collins
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada.,Department of Chemistry, Bucknell University, Lewisburg, PA 17837, USA
| | - Hugo Destaillats
- Indoor Environment Group, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - D James Donaldson
- Department of Chemistry, University of Toronto, Toronto, ON M5S 3H6, Canada.,Department of Physical and Environmental Sciences, University of Toronto, Toronto, ON M1C 1A4, Canada
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Jose L Jimenez
- Department of Chemistry and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder, Boulder, CO 80309, USA
| | - V Faye McNeill
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA
| | - Glenn C Morrison
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rachel E O'Brien
- Department of Chemistry, College of William and Mary, Williamsburg, VA 23185, USA
| | - Manabu Shiraiwa
- Department of Chemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Marina E Vance
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder, CO 80309, USA
| | - J R Wells
- National Institute for Occupational Safety and Health, Morgantown, WV 26505, USA
| | - Wei Xiong
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.,Materials Science and Engineering Program, University of California, San Diego, La Jolla, CA 92093, USA
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33
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Wylie ADL, Abbatt JPD. Heterogeneous Ozonolysis of Tetrahydrocannabinol: Implications for Thirdhand Cannabis Smoke. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:14215-14223. [PMID: 33147000 DOI: 10.1021/acs.est.0c03728] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Thirdhand smoke (THS) deposits to surfaces following smoking events and is a source of chemical exposure to humans. However, the evolution of THS in indoor environments is not well understood. Cannabis THS is a chemically distinct and prevalent form of THS, which has not been studied. The heterogeneous reaction of Δ9-tetrahydrocannabinol (THC), a major component of cannabis smoke, with ozone was examined as a pure compound and within cannabis smoke. Oxidative decay via ozonolysis and product formation were monitored by liquid chromatography-tandem mass spectrometry. Epoxide, dicarbonyl, and secondary ozonide THC reaction products were detected from both pure THC and cannabis experiments, with the product ratios dependent on relative humidity. The observed reaction kinetics for loss of THC on glass and cotton surfaces are consistent with a relatively short loss lifetime, which will be strongly dependent on the film thickness, ozone mixing ratio, and ozone reactivity of the surface substrate. The low volatility of THC and its oxidation products suggest that their contributions to thirdhand cannabis smoke will be less significant than the role that nicotine plays in thirdhand tobacco smoke.
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Affiliation(s)
- Aaron D L Wylie
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada
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34
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Zeng J, Mekic M, Xu X, Loisel G, Zhou Z, Gligorovski S, Li X. A Novel Insight into the Ozone-Skin Lipid Oxidation Products Observed by Secondary Electrospray Ionization High-Resolution Mass Spectrometry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:13478-13487. [PMID: 33085459 DOI: 10.1021/acs.est.0c05100] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Emissions of secondary products through reactions of oxidants, ozone (O3), and hydroxyl radical (·OH) with human skin lipids have become increasingly important in indoor environments. Here, we evaluate the secondary organic compounds formed through heterogeneous reactions of gaseous O3 with hand skin lipids by using a high-resolution quadrupole Orbitrap mass spectrometer coupled to a commercial secondary electrospray ionization (SESI) source. More than 600 ions were detected over a period of less than 40 min real-time measurements, among which 53 ions were characterized with a significant increasing trend in signal intensity at the presence of O3. Based on the detected ions, we suggest detailed reaction pathways initiated by ozone oxidation of squalene that results in primary and secondary ozonides; we noticed for the first time that these products may be further cleaved by direct reaction of nucleophilic ammonia (NH3), emitted from human skin. Finally, we estimate the fate of secondarily formed carbonyl compounds with respect to their gas-phase reactions with ·OH, O3, and NO3 and compared with their removal by air exchange rate (AER) with outdoors. The obtained results suggest that human presence is a source of an important number of organic compounds, which can significantly influence the air quality in indoor environments.
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Affiliation(s)
- Jiafa Zeng
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Majda Mekic
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
- University of Chinese Academy of Sciences, Beijing 10069, China
| | - Xin Xu
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Gwendal Loisel
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Zhen Zhou
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
| | - Sasho Gligorovski
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Xue Li
- Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China
- Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou, 510632, China
- Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 511443, China
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35
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Won Y, Lakey PSJ, Morrison G, Shiraiwa M, Rim D. Spatial distributions of ozonolysis products from human surfaces in ventilated rooms. INDOOR AIR 2020; 30:1229-1240. [PMID: 32478932 DOI: 10.1111/ina.12700] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 05/13/2020] [Accepted: 05/19/2020] [Indexed: 05/03/2023]
Abstract
Ozone has adverse effects on human health. Skin oil on the human surface acts as an ozone sink indoors, producing oxidation products that can cause skin and respiratory irritations. Concentrations of ozone and oxidation products near human surfaces, including the breathing zone, can be modulated by indoor ventilation modes and human surface conditions. The objective of this study is to examine concentrations and spatial heterogeneity of ozone and ozonolysis products under representative ranges of indoor ventilation, clothing, and breathing conditions. Using computational fluid dynamics (CFD) simulation in conjunction with a chemical kinetic model, details of ozone reactions with the human surface and subsequent chemical reactions are examined. The results show that primary ozonolysis products are concentrated near the soiled clothing, while the secondary products are relatively well distributed throughout the room. Increasing indoor air mixing enhances the ozone deposition to the human surface, thereby resulting in higher emission rates of oxidation products in the room. Soiled clothing consumes more ozone than clean clothing and accordingly produces ~ 65% more primary products and ~15% more secondary products. The results also reveal that unsaturated hydrocarbons from the human breath, such as isoprene, contribute to only ~0.5% of ozone removal compared to ozone deposition to the human surface.
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Affiliation(s)
- Youngbo Won
- Architectural Engineering Department, Pennsylvania State University, University Park, PA, USA
| | - Pascale S J Lakey
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
| | - Glenn Morrison
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC, USA
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, Irvine, CA, USA
| | - Donghyun Rim
- Architectural Engineering Department, Pennsylvania State University, University Park, PA, USA
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36
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Bekö G, Wargocki P, Wang N, Li M, Weschler CJ, Morrison G, Langer S, Ernle L, Licina D, Yang S, Zannoni N, Williams J. The Indoor Chemical Human Emissions and Reactivity (ICHEAR) project: Overview of experimental methodology and preliminary results. INDOOR AIR 2020; 30:1213-1228. [PMID: 32424858 DOI: 10.1111/ina.12687] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/20/2020] [Accepted: 05/11/2020] [Indexed: 05/03/2023]
Abstract
With the gradual reduction of emissions from building products, emissions from human occupants become more dominant indoors. The impact of human emissions on indoor air quality is inadequately understood. The aim of the Indoor Chemical Human Emissions and Reactivity (ICHEAR) project was to examine the impact on indoor air chemistry of whole-body, exhaled, and dermally emitted human bioeffluents under different conditions comprising human factors (t-shirts/shorts vs long-sleeve shirts/pants; age: teenagers, young adults, and seniors) and a variety of environmental factors (moderate vs high air temperature; low vs high relative humidity; presence vs absence of ozone). A series of human subject experiments were performed in a well-controlled stainless steel climate chamber. State-of-the-art measurement technologies were used to quantify the volatile organic compounds emitted by humans and their total OH reactivity; ammonia, nanoparticle, fluorescent biological aerosol particle (FBAP), and microbial emissions; and skin surface chemistry. This paper presents the design of the project, its methodologies, and preliminary results, comparing identical measurements performed with five groups, each composed of 4 volunteers (2 males and 2 females). The volunteers wore identical laundered new clothes and were asked to use the same set of fragrance-free personal care products. They occupied the ozone-free (<2 ppb) chamber for 3 hours (morning) and then left for a 10-min lunch break. Ozone (target concentration in occupied chamber ~35 ppb) was introduced 10 minutes after the volunteers returned to the chamber, and the measurements continued for another 2.5 hours. Under a given ozone condition, relatively small differences were observed in the steady-state concentrations of geranyl acetone, 6MHO, and 4OPA between the five groups. Larger variability was observed for acetone and isoprene. The absence or presence of ozone significantly influenced the steady-state concentrations of acetone, geranyl acetone, 6MHO, and 4OPA. Results of replicate experiments demonstrate the robustness of the experiments. Higher repeatability was achieved for dermally emitted compounds and their reaction products than for constituents of exhaled breath.
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Affiliation(s)
- Gabriel Bekö
- Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Lyngby, Denmark
| | - Pawel Wargocki
- Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Lyngby, Denmark
| | - Nijing Wang
- Max Planck Institute for Chemistry, Mainz, Germany
| | - Mengze Li
- Max Planck Institute for Chemistry, Mainz, Germany
| | - Charles J Weschler
- Department of Civil Engineering, International Centre for Indoor Environment and Energy, Technical University of Denmark, Lyngby, Denmark
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ, USA
| | - Glenn Morrison
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sarka Langer
- IVL Swedish Environmental Research Institute, Göteborg, Sweden
- Division of Building Services Engineering, Department of Architecture and Civil Engineering, Chalmers University of Technology, Göteborg, Sweden
| | - Lisa Ernle
- Max Planck Institute for Chemistry, Mainz, Germany
| | - Dusan Licina
- Human-Oriented Built Environment Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Fribourg, Switzerland
| | - Shen Yang
- Human-Oriented Built Environment Laboratory, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Fribourg, Switzerland
| | - Nora Zannoni
- Max Planck Institute for Chemistry, Mainz, Germany
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37
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Moccia G, De Caro F, Pironti C, Boccia G, Capunzo M, Borrelli A, Motta O. Development and Improvement of an Effective Method for Air and Surfaces Disinfection with Ozone Gas as a Decontaminating Agent. MEDICINA (KAUNAS, LITHUANIA) 2020; 56:E578. [PMID: 33143010 PMCID: PMC7694113 DOI: 10.3390/medicina56110578] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/20/2020] [Accepted: 10/28/2020] [Indexed: 11/16/2022]
Abstract
Background and objectives: Ozone has been one of the most investigated and discussed sanitization methods. This paper reports a procedure to sanitize air hospital environments, in particular chirurgical surgery rooms that require high levels of disinfection. The purpose of this work was the development and implementation of a cleansing and sanitizing procedure for critical clinical settings with ozone, to prevent hospital infections by the elimination of all toxic and harmful microorganisms in the air, and ensure safe use for operators and patients. Materials and Methods: The protocol for the study involved a structured selection of a representative environment of healthcare structures such as high, medium, and low-risk settings in air and examples of hospital furniture. Results: The concentration of ozone was measured during sanitization treatment and the estimation of the total microbial count in the air and on different surfaces before and after the sanitization operations was performed. The results demonstrated a significant reduction in the microbial count that always fell below the threshold value. Conclusions: Currently, there are no air treatment strategies available for inactivating airborne organisms during hospital outbreaks, which is most probably due to the lack of approved protocols.
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Affiliation(s)
- Giuseppina Moccia
- Department of Medicine Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, via S. Allende 1, 84081 Baronissi (SA), Italy; (G.M.); (F.D.C.); (G.B.); (M.C.); (O.M.)
| | - Francesco De Caro
- Department of Medicine Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, via S. Allende 1, 84081 Baronissi (SA), Italy; (G.M.); (F.D.C.); (G.B.); (M.C.); (O.M.)
| | - Concetta Pironti
- Department of Medicine Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, via S. Allende 1, 84081 Baronissi (SA), Italy; (G.M.); (F.D.C.); (G.B.); (M.C.); (O.M.)
- University Hospital “San Giovanni di Dio e Ruggi D’Aragona”, via S. Leonardo, 1, 84131 Salerno, Italy;
| | - Giovanni Boccia
- Department of Medicine Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, via S. Allende 1, 84081 Baronissi (SA), Italy; (G.M.); (F.D.C.); (G.B.); (M.C.); (O.M.)
| | - Mario Capunzo
- Department of Medicine Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, via S. Allende 1, 84081 Baronissi (SA), Italy; (G.M.); (F.D.C.); (G.B.); (M.C.); (O.M.)
| | - Anna Borrelli
- University Hospital “San Giovanni di Dio e Ruggi D’Aragona”, via S. Leonardo, 1, 84131 Salerno, Italy;
| | - Oriana Motta
- Department of Medicine Surgery and Dentistry “Scuola Medica Salernitana”, University of Salerno, via S. Allende 1, 84081 Baronissi (SA), Italy; (G.M.); (F.D.C.); (G.B.); (M.C.); (O.M.)
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38
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Yao M, Weschler CJ, Zhao B, Zhang L, Ma R. Breathing-rate adjusted population exposure to ozone and its oxidation products in 333 cities in China. ENVIRONMENT INTERNATIONAL 2020; 138:105617. [PMID: 32155513 DOI: 10.1016/j.envint.2020.105617] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 05/28/2023]
Abstract
While PM2.5 (particles with aerodynamic diameter less than 2.5 µm) concentrations in China are beginning to decline because of pollution abatement measures, ozone (O3) concentrations continue to rise. In this study, we have used a Monte Carlo approach to estimate breathing-rate adjusted (BRA) population exposure to ozone and its oxidation products based on hourly O3 measurements collected in 2017 from monitoring stations in 333 Chinese cities. The median measured outdoor O3 concentration in these cities was 31 ppb, while the median calculated indoor concentrations of ozone and ozone-derived oxidation products were 7.5 ppb and 21 ppb, respectively. The median BRA O3 exposure concentration was 12 ppb, ranging from 2.2 ppb to 18 ppb among the cities. Eastern and central cities had higher exposure concentrations, while northeastern and western cities had lower. On average, the residents of these cities spent 88% of their time indoors. Consequently, even with breathing rate adjustments, indoor O3 exposure averaged 50% of the total O3 exposure nationwide. The median BRA exposure concentration for ozone-derived products was 18 ppb, ranging from 4.5 ppb to 32 ppb among the cities. On average, BRA exposure concentrations were 1.6 times larger for oxidation products than for ozone, while seasonal variations of exposure concentrations were smaller for oxidation products than for ozone. As many of the products of indoor ozone chemistry are toxic, the health consequences of exposure to such products should be further investigated.
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Affiliation(s)
- Mingyao Yao
- Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084, China
| | - Charles J Weschler
- Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084, China; Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, NJ 08854, USA; International Centre for Indoor Environment and Energy, Technical University of Denmark, Lyngby, Denmark.
| | - Bin Zhao
- Department of Building Science, School of Architecture, Tsinghua University, Beijing 100084, China; Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing 100084, China.
| | - Lin Zhang
- Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, China
| | - Rui Ma
- Department of Electronic Engineering, Tsinghua University, China
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39
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von Domaros M, Lakey PSJ, Shiraiwa M, Tobias DJ. Multiscale Modeling of Human Skin Oil-Induced Indoor Air Chemistry: Combining Kinetic Models and Molecular Dynamics. J Phys Chem B 2020; 124:3836-3843. [DOI: 10.1021/acs.jpcb.0c02818] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Michael von Domaros
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Pascale S. J. Lakey
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Douglas J. Tobias
- Department of Chemistry, University of California, Irvine, California 92697, United States
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40
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Abbatt JPD, Wang C. The atmospheric chemistry of indoor environments. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:25-48. [PMID: 31712796 DOI: 10.1039/c9em00386j] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Through air inhalation, dust ingestion and dermal exposure, the indoor environment plays an important role in controlling human chemical exposure. Indoor emissions and chemistry can also have direct impacts on the quality of outdoor air. And so, it is important to have a strong fundamental knowledge of the chemical processes that occur in indoor environments. This review article summarizes our understanding of the indoor chemistry field. Using a molecular perspective, it addresses primarily the new advances that have occurred in the past decade or so and upon developments in our understanding of multiphase partitioning and reactions. A primary goal of the article is to contrast indoor chemistry to that which occurs outdoors, which we know to be a strongly gas-phase, oxidant-driven system in which substantial oxidative aging of gases and aerosol particles occurs. By contrast, indoor environments are dark, gas-phase oxidant concentrations are relatively low, and due to air exchange, only short times are available for reactive processing of gaseous and particle constituents. However, important gas-surface partitioning and reactive multiphase chemistry occur in the large surface reservoirs that prevail in all indoor environments. These interactions not only play a crucial role in controlling the composition of indoor surfaces but also the surrounding gases and aerosol particles, thus affecting human chemical exposure. There are rich research opportunities available if the advanced measurement and modeling tools of the outdoor atmospheric chemistry community continue to be brought indoors.
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Affiliation(s)
- Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada.
| | - Chen Wang
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada.
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41
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Arata C, Heine N, Wang N, Misztal PK, Wargocki P, Bekö G, Williams J, Nazaroff WW, Wilson KR, Goldstein AH. Heterogeneous Ozonolysis of Squalene: Gas-Phase Products Depend on Water Vapor Concentration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:14441-14448. [PMID: 31757120 DOI: 10.1021/acs.est.9b05957] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Previous work examining the condensed-phase products of squalene particle ozonolysis found that an increase in water vapor concentration led to lower concentrations of secondary ozonides, increased concentrations of carbonyls, and smaller particle diameter, suggesting that water changes the fate of the Criegee intermediate. To determine if this volume loss corresponds to an increase in gas-phase products, we measured gas-phase volatile organic compound (VOC) concentrations via proton-transfer-reaction time-of-flight mass spectrometry. Studies were conducted in a flow-tube reactor at atmospherically relevant ozone (O3) exposure levels (5-30 ppb h) with pure squalene particles. An increase in water vapor concentration led to strong enhancement of gas-phase oxidation products at all tested O3 exposures. An increase in water vapor from near zero to 70% relative humidity (RH) at high O3 exposure increased the total mass concentration of gas-phase VOCs by a factor of 3. The observed fraction of carbon in the gas-phase correlates with the fraction of particle volume lost. Experiments involving O3 oxidation of shirts soiled with skin oil confirms that the RH dependence of gas-phase reaction product generation occurs similarly on surfaces containing skin oil under realistic conditions. Similar behavior is expected for O3 reactions with other surface-bound organics containing unsaturated carbon bonds.
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Affiliation(s)
| | - Nadja Heine
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Nijing Wang
- Air Chemistry Department , Max Planck Institute for Chemistry , 55128 Mainz , Germany
| | | | - Pawel Wargocki
- Department of Civil Engineering , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark
| | - Gabriel Bekö
- Department of Civil Engineering , Technical University of Denmark , 2800 Kgs. Lyngby , Denmark
| | - Jonathan Williams
- Air Chemistry Department , Max Planck Institute for Chemistry , 55128 Mainz , Germany
| | | | - Kevin R Wilson
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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42
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Won Y, Waring M, Rim D. Understanding the Spatial Heterogeneity of Indoor OH and HO 2 due to Photolysis of HONO Using Computational Fluid Dynamics Simulation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:14470-14478. [PMID: 31693359 DOI: 10.1021/acs.est.9b06315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Indoor photolysis of nitrous acid (HONO) generates hydroxyl radicals (OH), and since OH is fast reacting, it may be confined within the HONO-photolyzing indoor volume of light. This study investigated the HONO-photolysis-induced formation of indoor OH, the transformation of OH to hydroperoxy radicals (HO2), and resulting spatial distributions of those radicals and their oxidation products. To do so, a computational fluid dynamics (CFD) model framework was established to simulate HONO photolysis in a room and subsequent reactions associated with OH and HO2 under a typical range of indoor lighting and ventilation conditions. The results showed that OH and HO2 were essentially confined in the volume of HONO-photolyzing light, but oxidation products were relatively well distributed throughout the room. As the light volume increased, more total in-room OH was produced, thereby increasing oxidation product concentrations. Spatial distributions of OH and HO2 varied by the type of artificial light (e.g., fluorescent versus incandescent), due to differences in photon flux as a function of light source and the distance from the source. The HO2 generation rate and air change rate made notable impacts on product concentrations.
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Affiliation(s)
- Youngbo Won
- Department of Architectural Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Michael Waring
- Department of Civil, Architectural and Environmental Engineering , Drexel University , Philadelphia , Pennsylvania 19104 , United States
| | - Donghyun Rim
- Department of Architectural Engineering , Pennsylvania State University , University Park , Pennsylvania 16802 , United States
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