51
|
Young CJ, Zhou S, Siegel JA, Kahan TF. Illuminating the dark side of indoor oxidants. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1229-1239. [PMID: 31173015 DOI: 10.1039/c9em00111e] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The chemistry of oxidants and their precursors (oxidants*) plays a central role in outdoor environments but its importance in indoor air remains poorly understood. Ozone (O3) chemistry is important in some indoor environments and, until recently, ozone was thought to be the dominant oxidant indoors. There is now evidence that formation of the hydroxyl radical by photolysis of nitrous acid (HONO) and formaldehyde (HCHO) may be important indoors. In the past few years, high time-resolution measurements of oxidants* indoors have become more common and the importance of event-based release of oxidants* during activities such as cleaning has been proposed. Here we review the current understanding of oxidants* indoors, including drivers of the formation and loss of oxidants*, levels of oxidants* in indoor environments, and important directions for future research.
Collapse
Affiliation(s)
- Cora J Young
- Department of Chemistry, York University, Canada.
| | | | | | | |
Collapse
|
52
|
Xiong J, He Z, Tang X, Misztal PK, Goldstein AH. Modeling the Time-Dependent Concentrations of Primary and Secondary Reaction Products of Ozone with Squalene in a University Classroom. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:8262-8270. [PMID: 31260270 DOI: 10.1021/acs.est.9b02302] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Volatile organic chemicals are produced from reactions of ozone with squalene in human skin oil. Both primary and secondary reaction products, i.e., 6-methyl-5-hepten-2-one (6-MHO) and 4-oxopentanal (4-OPA), have been reported in indoor occupied spaces. However, the abundance of these products indoors is a function of many variables, including the amount of ozone and occupants present as well as indoor removal processes. In this study, we develop a time-dependent kinetic model describing the behavior of ozone/squalene reaction products indoors, including the reaction process and physical adsorption process of products on indoor surfaces. The key parameters in the model were obtained by fitting time-resolved concentrations of 6-MHO, 4-OPA, and ozone in a university classroom on 1 day with multiple class sessions. The model predictions were subsequently tested against observations from four additional measurement days in the same classroom. Model predictions and experimental data agreed well (R2 = 0.87-0.92) for all test days, including ∼7 class sessions covering a range of occupants (10-70) and ozone concentrations (0.09-32 ppb), demonstrating the effectiveness of the model. Accounting for surface uptake of 6-MHO and 4-OPA significantly improved model predictions (R2 = 0.52-0.76 without surface uptake), reflecting the importance of including surface interactions to quantitatively represent product behavior in indoor environments.
Collapse
Affiliation(s)
- Jianyin Xiong
- School of Mechanical Engineering , Beijing Institute of Technology , Beijing 100081 , People's Republic of China
| | - Zhangcan He
- School of Mechanical Engineering , Beijing Institute of Technology , Beijing 100081 , People's Republic of China
| | - Xiaochen Tang
- Indoor Environment Group, Energy Technologies Area , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Pawel K Misztal
- Centre for Ecology & Hydrology , Edinburgh , Midlothian EH26 0QB , United Kingdom
| | | |
Collapse
|
53
|
Xiang J, Weschler CJ, Zhang J, Zhang L, Sun Z, Duan X, Zhang Y. Ozone in urban China: Impact on mortalities and approaches for establishing indoor guideline concentrations. INDOOR AIR 2019; 29:604-615. [PMID: 31077433 DOI: 10.1111/ina.12565] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/12/2019] [Accepted: 05/07/2019] [Indexed: 05/03/2023]
Abstract
Reducing indoor ozone levels may be an effective strategy to reduce total exposure and associated mortality. Here we estimate (a) premature mortalities attributable to ozone for China's urban population ≥25 years of age; (b) the fraction of total exposure occurring indoors; and (c) mortalities that can be potentially avoided through meeting current and more stringent indoor ozone standards/guidelines based on 1-hour daily maxima. To estimate ozone-attributable premature mortalities, we used hourly outdoor ozone concentrations measured at 1497 monitoring stations located in 339 Chinese cities and a published concentration-response model. We proceeded to estimate province-specific infiltration factors and co-occurring hourly indoor ozone concentrations. For the year 2015, we estimated that indoor exposures accounted for 59% (95% confidence interval (CI): 26%-79%) of the total ozone exposure that resulted in 70800 (95% CI: 35 900-137 700) premature all-cause mortalities in urban China. If the current Chinese indoor ozone standards (80 ppbv (160 µg/m3 ); 56 ppbv (112 µg/m3 )) were met, the mean estimates of reduction in mortalities would be indistinguishable from zero. With stricter 1-hour indoor ozone guidelines, the expected mortality reductions increase exponentially per unit decrease in indoor ozone. The analysis in this paper should help facilitate formulating present and future indoor ozone guidelines.
Collapse
Affiliation(s)
- Jianbang Xiang
- Department of Building Science, Tsinghua University, Beijing, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing, China
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Charles J Weschler
- Department of Building Science, Tsinghua University, Beijing, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing, China
- Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey
| | - Junfeng Zhang
- Global Health Institute and the Nicholas School of Environment, Duke University, Durham, North Carolina
- Global and Environmental Health, Duke Kunshan University, Kunshan, Jiangsu, China
| | - Lin Zhang
- Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, Shenzhen, Guangdong, China
| | - Zhiwei Sun
- Department of Building Science, Tsinghua University, Beijing, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing, China
| | - Xiaoli Duan
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, China
| | - Yinping Zhang
- Department of Building Science, Tsinghua University, Beijing, China
- Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing, China
| |
Collapse
|
54
|
Lakey PSJ, Morrison GC, Won Y, Parry KM, von Domaros M, Tobias DJ, Rim D, Shiraiwa M. The impact of clothing on ozone and squalene ozonolysis products in indoor environments. Commun Chem 2019. [DOI: 10.1038/s42004-019-0159-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
|
55
|
Eudier F, Hucher N, Picard C, Savary G, Grisel M. Squalene Oxidation Induced by Urban Pollutants: Impact on Skin Surface Physico-Chemistry. Chem Res Toxicol 2019; 32:285-293. [PMID: 30681332 DOI: 10.1021/acs.chemrestox.8b00311] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of urban pollutants on skin properties has been revealed through several epidemiological studies. However, comprehension of involved mechanisms remains undetermined. In addition, the impact of such stressors on skin surface properties, especially skin physico-chemistry, has not been investigated. Consequently, the present study aims to develop a new aging protocol able to highlight the impact of selected urban pollutants on a model sebaceous lipid: the squalene. Its quality has been followed during aging using LC-MS analysis. Results showed that the quality of the control solution containing only squalene remains stable during 45 days, whereas the quality of the solution containing squalene mixed with pollutants appears greatly altered, especially in the presence of heavy metals: a large amount of oxidation compounds was evidenced due to oxidation and dehydrogenation mechanisms. In addition, a physicochemical study was performed using a validated nonbiological skin model able to mimic skin physico-chemistry. Surface free energy components were calculated using contact angle measurements according to the Van Oss model. The application of degraded squalene significantly increased skin hydrophilic and monopolar behavior compared to the application of control squalene. Those modifications are essentially explained by the nature of squalene oxidation products. It must be noted from this study that squalene oxidation due to pollutants or due to high temperature did not lead to the same physicochemical consequences neither to the same oxidation products, as shown by thermal analysis. This study gives original and precious information to explain alterations induced by pollutants on skin surface properties, especially skin chemistry and physico-chemistry.
Collapse
Affiliation(s)
- Florine Eudier
- UNILEHAVRE, FR 3038 CNRS, URCOM, EA 3221 , Normandie University, France , 25 rue Philippe Lebon BP 1123 , 76063 Le Havre cedex , France
| | - Nicolas Hucher
- UNILEHAVRE, FR 3038 CNRS, URCOM, EA 3221 , Normandie University, France , 25 rue Philippe Lebon BP 1123 , 76063 Le Havre cedex , France
| | - Céline Picard
- UNILEHAVRE, FR 3038 CNRS, URCOM, EA 3221 , Normandie University, France , 25 rue Philippe Lebon BP 1123 , 76063 Le Havre cedex , France
| | - Géraldine Savary
- UNILEHAVRE, FR 3038 CNRS, URCOM, EA 3221 , Normandie University, France , 25 rue Philippe Lebon BP 1123 , 76063 Le Havre cedex , France
| | - Michel Grisel
- UNILEHAVRE, FR 3038 CNRS, URCOM, EA 3221 , Normandie University, France , 25 rue Philippe Lebon BP 1123 , 76063 Le Havre cedex , France
| |
Collapse
|
56
|
Schwartz-Narbonne H, Wang C, Zhou S, Abbatt JPD, Faust J. Heterogeneous Chlorination of Squalene and Oleic Acid. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:1217-1224. [PMID: 30387352 DOI: 10.1021/acs.est.8b04248] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Washing with chlorine bleach leads to high mixing ratios of gas-phase HOCl. Using two methods that are sensitive to surface film composition-attenuated total reflection fourier transform infrared (ATR-FTIR) spectroscopy and direct analysis in real time mass spectrometry (DART-MS)-we present the first study of the chlorination chemistry that occurs when gaseous HOCl reacts with thin films of squalene and oleic acid. At mixing ratios of 600 ppbv, HOCl forms chlorohydrins by adding across carbon-carbon double bonds without breaking the carbon backbone. The initial uptake of one HOCl molecule occurs on the time scale of a few minutes at these mixing ratios. For oleic acid, ester formation proceeds immediately thereafter, leading to dimeric and trimeric chlorinated products. For squalene, subsequent HOCl uptake occurs until all six of its carbon-carbon double bonds become chlorinated within 1-2 h. These results indicate that chlorination of skin oil, which contains substantial carbon unsaturation, is likely to occur rapidly under common cleaning conditions, potentially leading to the irritation associated with chlorinated bleach. This chemistry will likely also proceed with cooking oils, in the human respiratory system which has unsaturated surfactants as important components of lung fluid, and with organic components of the sea surface microlayer.
Collapse
Affiliation(s)
| | - Chen Wang
- Department of Chemistry , University of Toronto , Toronto , ON Canada M5S 3H6
| | - Shouming Zhou
- Department of Chemistry , University of Toronto , Toronto , ON Canada M5S 3H6
| | - Jonathan P D Abbatt
- Department of Chemistry , University of Toronto , Toronto , ON Canada M5S 3H6
| | - Jennifer Faust
- Department of Chemistry , University of Toronto , Toronto , ON Canada M5S 3H6
- Department of Chemistry , College of Wooster , Wooster , Ohio 44691 , United States
| |
Collapse
|
57
|
Affiliation(s)
- Sasho Gligorovski
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510 640, China.
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto M5S 3H6, Canada.
| |
Collapse
|
58
|
Abstract
This review aims to encapsulate the importance, ubiquity, and complexity of indoor chemistry. We discuss the many sources of indoor air pollutants and summarize their chemical reactions in the air and on surfaces. We also summarize some of the known impacts of human occupants, who act as sources and sinks of indoor chemicals, and whose activities (e.g., cooking, cleaning, smoking) can lead to extremely high pollutant concentrations. As we begin to use increasingly sensitive and selective instrumentation indoors, we are learning more about chemistry in this relatively understudied environment.
Collapse
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, Department of Civil Engineering , Technical University of Denmark , Lyngby , Denmark
| | - Nicola Carslaw
- Environment Department , University of York , York , North Yorkshire YO10 5NG , U.K
| |
Collapse
|
59
|
Heine N, Houle FA, Wilson KR. Connecting the Elementary Reaction Pathways of Criegee Intermediates to the Chemical Erosion of Squalene Interfaces during Ozonolysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:13740-13748. [PMID: 29120614 DOI: 10.1021/acs.est.7b04197] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Criegee intermediates (CI), formed in alkene ozonolysis, are central for controlling the multiphase chemistry of organic molecules in both indoor and outdoor environments. Here, we examine the heterogeneous ozonolysis of squalene, a key species in indoor air chemistry. Aerosol mass spectrometry is used to investigate how the ozone (O3) concentration, relative humidity (RH), and particle size control reaction rates and mechanisms. Although the reaction rate is found to be independent of RH, the reaction products and particle size depend upon H2O. Under dry conditions (RH = 3%) the reaction produces high-molecular-weight secondary ozonides (SOZ), which are known skin irritants, and a modest change in particle size. Increasing the RH reduces the aerosol size by 30%, while producing mainly volatile aldehyde products, increases potential respiratory exposure. Chemical kinetics simulations link the elementary reactions steps of CI to the observed kinetics, product distributions, and changes in particle size. The simulations reveal that ozonolysis occurs near the surface and is O3-transport limited. The observed secondary ozonides are consistent with the formation of mainly secondary CI, in contrast to gas-phase ozonolysis mechanisms.
Collapse
Affiliation(s)
- Nadja Heine
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Frances A Houle
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| | - Kevin R Wilson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
| |
Collapse
|
60
|
Wells JR, Schoemaecker C, Carslaw N, Waring MS, Ham JE, Nelissen I, Wolkoff P. Reactive indoor air chemistry and health-A workshop summary. Int J Hyg Environ Health 2017; 220:1222-1229. [PMID: 28964679 PMCID: PMC6388628 DOI: 10.1016/j.ijheh.2017.09.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/18/2017] [Accepted: 09/22/2017] [Indexed: 12/23/2022]
Abstract
The chemical composition of indoor air changes due to the reactive nature of the indoor environment. Historically, only the stable parent compounds were investigated due to their ease of measurement by conventional methods. Today, however, scientists can better characterize oxidation products (gas and particulate-phase) formed by indoor chemistry. An understanding of occupant exposure can be developed through the investigation of indoor oxidants, the use of derivatization techniques, atmospheric pressure detection, the development of real-time technologies, and improved complex modeling techniques. Moreover, the connection between exposure and health effects is now receiving more attention from the research community. Nevertheless, a need still exists for improved understanding of the possible link between indoor air chemistry and observed acute or chronic health effects and long-term effects such as work-related asthma.
Collapse
Affiliation(s)
- J R Wells
- NIOSH/HELD/EAB, Morgantown, WV, USA.
| | | | - N Carslaw
- Environment Department, University of York, York, UK
| | - M S Waring
- Drexel University, Philadelphia, PA, USA
| | - J E Ham
- NIOSH/HELD/EAB, Morgantown, WV, USA
| | - I Nelissen
- Flemish Institute for Technological Research (VITO), Mol, Belgium
| | - P Wolkoff
- National Research Center for the Working Environment, Copenhagen, Denmark
| |
Collapse
|
61
|
Weschler CJ, Nazaroff WW. Growth of organic films on indoor surfaces. INDOOR AIR 2017; 27:1101-1112. [PMID: 28556424 DOI: 10.1111/ina.12396] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/19/2017] [Indexed: 05/07/2023]
Abstract
We present a model for the growth of organic films on impermeable indoor surfaces. The model couples transport through a gas-side boundary layer adjacent to the surface with equilibrium partitioning of semivolatile organic compounds (SVOCs) between the gas phase and the surface film. Model predictions indicate that film growth would primarily be influenced by the gas-phase concentration of SVOCs with octanol-air partitioning (Koa ) values in the approximate range 10≤log Koa ≤13. Within the relevant range, SVOCs with lower values will equilibrate with the surface film more rapidly. Over time, the film becomes relatively enriched in species with higher log Koa values, while the proportion of gas-phase SVOCs not in equilibrium with the film decreases. Given stable airborne SVOC concentrations, films grow at faster rates initially and then subsequently diminish to an almost steady growth rate. Once an SVOC is equilibrated with the film, its mass per unit film volume remains constant, while its mass per unit area increases in proportion to overall film thickness. The predictions of the conceptual model and its mathematical embodiment are generally consistent with results reported in the peer-reviewed literature.
Collapse
Affiliation(s)
- C 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
| | - W W Nazaroff
- Department of Civil and Environmental Engineering, University of California, Berkeley, Berkeley, CA, USA
| |
Collapse
|
62
|
Liu S, Thompson SL, Stark H, Ziemann PJ, Jimenez JL. Gas-Phase Carboxylic Acids in a University Classroom: Abundance, Variability, and Sources. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:5454-5463. [PMID: 28420232 DOI: 10.1021/acs.est.7b01358] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Gas-phase carboxylic acids are ubiquitous in ambient air, yet their indoor occurrence and abundance are poorly characterized. To fill this gap, we measured gas-phase carboxylic acids in real-time inside and outside of a university classroom using a high-resolution time-of-flight chemical ionization mass spectrometer (HRToF-CIMS) equipped with an acetate ion source. A wide variety of carboxylic acids were identified indoors and outdoors, including monoacids, diacids, hydroxy acids, carbonyl acids, and aromatic acids. An empirical parametrization was derived to estimate the sensitivity (ion counts per ppt of the analytes) of the HRToF-CIMS to the acids. The campaign-average concentration of carboxylic acids measured outdoors was 1.0 ppb, with the peak concentration occurring in daytime. The average indoor concentration of carboxylic acids was 6.8 ppb, of which 87% was contributed by formic and lactic acid. While carboxylic acids measured outdoors displayed a single daytime peak, those measured indoors displayed a daytime and a nighttime peak. Besides indoor sources such as off-gassing of building materials, evidence for acid production from indoor chemical reactions with ozone was found. In addition, some carboxylic acids measured indoors correlated to CO2 in daytime, suggesting that human occupants may contribute to their abundance either through direct emissions or surface reactions.
Collapse
Affiliation(s)
- Shang Liu
- Department of Chemistry & Biochemistry, and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado , Boulder, Colorado 80309, United States
| | - Samantha L Thompson
- Department of Chemistry & Biochemistry, and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado , Boulder, Colorado 80309, United States
| | - Harald Stark
- Department of Chemistry & Biochemistry, and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado , Boulder, Colorado 80309, United States
- Aerodyne Research Inc. , Billerica, Massachusetts 01821, United States
| | - Paul J Ziemann
- Department of Chemistry & Biochemistry, and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado , Boulder, Colorado 80309, United States
| | - Jose L Jimenez
- Department of Chemistry & Biochemistry, and Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado , Boulder, Colorado 80309, United States
| |
Collapse
|
63
|
Jacobs MI, Xu B, Kostko O, Heine N, Ahmed M, Wilson KR. Probing the Heterogeneous Ozonolysis of Squalene Nanoparticles by Photoemission. J Phys Chem A 2016; 120:8645-8656. [DOI: 10.1021/acs.jpca.6b09061] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael I. Jacobs
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Bo Xu
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Oleg Kostko
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Nadja Heine
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Musahid Ahmed
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kevin R. Wilson
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| |
Collapse
|