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Abbatt JPD, Morrison GC, Grassian VH, Shiraiwa M, Weschler CJ, Ziemann PJ. How should we define an indoor surface? INDOOR AIR 2022; 32:e12955. [PMID: 35104002 DOI: 10.1111/ina.12955] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/23/2021] [Accepted: 10/27/2021] [Indexed: 06/14/2023]
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Liu T, Abbatt JPD. Oxidation of sulfur dioxide by nitrogen dioxide accelerated at the interface of deliquesced aerosol particles. Nat Chem 2021; 13:1173-1177. [PMID: 34594012 DOI: 10.1038/s41557-021-00777-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 07/20/2021] [Indexed: 02/08/2023]
Abstract
Although the multiphase chemistry of SO2 in aerosol particles is of great importance to air quality under polluted haze conditions, a fundamental understanding of the pertinent mechanisms and kinetics is lacking. In particular, there is considerable debate on the importance of NO2 in the oxidation of SO2 in aerosol particles. Here experiments with atmospherically relevant deliquesced particles at buffered pH values of 4-5 show that the effective rate constant for the reaction of NO2 with SO32- ((1.4 ± 0.5) × 1010 M-1 s-1) is more than three orders of magnitude larger than the value in dilute solutions. An interfacial reaction at the surface of aerosol particles probably drives the very fast kinetics. Our results indicate that oxidation of SO2 by NO2 at aerosol surfaces may be an important source of sulfate aerosols under polluted haze conditions.
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Schneider SR, Lee K, Santos G, Abbatt JPD. Air Quality Data Approach for Defining Wildfire Influence: Impacts on PM 2.5, NO 2, CO, and O 3 in Western Canadian Cities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:13709-13717. [PMID: 34609856 DOI: 10.1021/acs.est.1c04042] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
As the climate warms, it is recognized that wildfires are increasing in size and frequency. The negative effects of wildfires on air quality are well documented, especially on commonly monitored atmospheric pollutants such as PM2.5, NO2, CO, and O3. However, it is not clear how frequently wildfires influence urban air quality and the size of that influence relative to traffic and industrial pollutants. To understand the impact of wildfires on air quality, we have established an automated method to identify wildfire-influenced ambient air measurements. The trajectory-fire interception method (TFIM) compares hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) back-trajectories from an air quality monitoring station to satellite imagery of fire "hot-spots" to determine the number of trajectory-fire interceptions that occur. From the number of interceptions and local PM2.5 measurements, we have defined a wildfire-influenced period to occur if the interception count is ≥20. TFIM wildfire identification compares favorably with Environment and Climate Change Canada's smoke forecast, FireWork, and with the BlueSky trajectory-based forecast. Using TFIM, we studied the impact of wildfire-influenced periods on PM2.5, NO2, CO, and O3 from 2001 to 2019 in Western Canadian urban areas. We show that wildfire-influenced periods have elevated concentrations of PM2.5, NO2, and CO but not O3. We show that a decreasing urban baseline of CO and NO2 over time results in a relatively greater impact of wildfires on these pollutants, which emphasizes the changing relative importance of wildfires on air quality.
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Schwartz-Narbonne H, Abbatt JPD, DeCarlo PF, Farmer DK, Mattila JM, Wang C, Donaldson DJ, Siegel JA. Modeling the Removal of Water-Soluble Trace Gases from Indoor Air via Air Conditioner Condensate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10987-10993. [PMID: 34342979 DOI: 10.1021/acs.est.1c02053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Water-soluble trace gas (WSTG) loss from indoor air via air conditioning (AC) units has been observed in several studies, but these results have been difficult to generalize. In the present study, we designed a box model that can be used to investigate and estimate WSTG removal due to partitioning to AC coil condensate. We compared the model output to measurements of a suite of organic acids cycling in an indoor environment and tested the model by varying the input AC parameters. These tests showed that WSTG loss via AC cycling is influenced by Henry's law constant of the compound in question, which is controlled by air and water temperatures and the condensate pH. Air conditioning unit specifications also impact WSTG loss through variations in the sensible heat ratio, the effective recirculation rate of air through the unit, and the timing of coil and fan operation. These findings have significant implications for indoor modeling. To accurately model the fate of indoor WSTGs, researchers must either measure or otherwise account for these unique environmental and operational characteristics.
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Osborne IS, Sugden AM, Rai TS, Funk MA, Malo CS, Hines PJ, Szuromi P, Lavine MS, Erkes DA, Jiang D, Nusinovich Y, Smith KT, Ferrarelli LK, Yeston J, Ray LB, Abbatt JPD. This Week in Science. Science 2021. [DOI: 10.1126/science.2021.372.6547.twis] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Abbatt JPD. Atmospheric ozone and pandemic lockdowns. Science 2021. [DOI: 10.1126/science.372.6547.1162-h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Liu T, Chan AWH, Abbatt JPD. Multiphase Oxidation of Sulfur Dioxide in Aerosol Particles: Implications for Sulfate Formation in Polluted Environments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:4227-4242. [PMID: 33760581 DOI: 10.1021/acs.est.0c06496] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atmospheric oxidation of sulfur dioxide (SO2) forms sulfate-containing aerosol particles that impact air quality, climate, and human and ecosystem health. It is well-known that in-cloud oxidation of SO2 frequently dominates over gas-phase oxidation on regional and global scales. Multiphase oxidation involving aerosol particles, fog, and cloud droplets has been generally thought to scale with liquid water content (LWC) so multiphase oxidation would be negligible for aerosol particles due to their low aerosol LWC. However, recent field evidence, particularly from East Asia, shows that fast sulfate formation prevails in cloud-free environments that are characterized by high aerosol loadings. By assuming that the kinetics of cloud water chemistry prevails for aerosol particles, most atmospheric models do not capture this phenomenon. Therefore, the field of aerosol SO2 multiphase chemistry has blossomed in the past decade, with many oxidation processes proposed to bridge the difference between modeled and observed sulfate mass loadings. This review summarizes recent advances in the fundamental understanding of the aerosol multiphase oxidation of SO2, with a focus on environmental conditions that affect the oxidation rate, experimental challenges, mechanisms and kinetics results for individual reaction pathways, and future research directions. Compared to dilute cloud water conditions, this paper highlights the differences that arise at the molecular level with the extremely high solute strengths present in aerosol particles.
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Schneider SR, Lakey PSJ, Shiraiwa M, Abbatt JPD. Reactive Uptake of Ozone to Simulated Seawater: Evidence for Iodide Depletion. J Phys Chem A 2020; 124:9844-9853. [PMID: 33196200 DOI: 10.1021/acs.jpca.0c08917] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of ozone with iodide in the ocean is a major ozone dry deposition pathway, as well as an important source of reactive iodine to the marine troposphere. Few prior laboratory experiments have been conducted with environmentally relevant ozone mixing ratios and iodide concentrations, leading to uncertainties in the rate of the reaction under marine boundary layer conditions. As well, there remains disagreement in the literature assessment of the relative contributions of an interfacial reaction via ozone adsorbed to the ocean surface versus a bulk reaction with dissolved ozone. In this study, we measure the uptake coefficient of ozone over a buffered, pH 8 salt solution replicating the concentrations of iodide, bromide, and chloride in the ocean over an ozone mixing ratio of 60-500 ppb. Due to iodide depletion in the solution, the measured ozone uptake coefficient is dependent on the exposure time of the solution to ozone and its mixing ratio. A kinetic multilayer model confirms that iodide depletion is occurring not only within ozone's reactodiffusive depth, which is on the order of microns for environmental conditions, but also deeper into the solution as well. Best model-measurement agreement arises when some degree of nondiffusive mixing is occurring in the solution, transporting iodide from deeper in the solution to a thin, diffusively mixed upper layer. If such mixing occurs rapidly in the environment, iodide depletion is unlikely to reduce ozone dry deposition rates. Unrealistically high bulk-to-interface partitioning of iodide is required for the model to predict a substantial interfacial component to the reaction, indicating that the Langmuir-Hinshelwood mechanism is not dominant under environmental conditions.
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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: 3] [Impact Index Per Article: 0.8] [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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Wang C, Bottorff B, Reidy E, Rosales CMF, Collins DB, Novoselac A, Farmer DK, Vance ME, Stevens PS, Abbatt JPD. Cooking, Bleach Cleaning, and Air Conditioning Strongly Impact Levels of HONO in a House. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:13488-13497. [PMID: 33064464 DOI: 10.1021/acs.est.0c05356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The relative importance of common activities on indoor nitrous acid (HONO) mixing ratios was explored during high time resolution, month-long measurements by chemical ionization mass spectrometry in a previously unoccupied house. Indoor HONO varied from 0.2 to 84.0 ppb (mean: 5.5 ppb; median 3.8 ppb), an order of magnitude higher than simultaneously measured outdoor values, indicating important indoor sources. They agree well with simultaneous measurements of HONO by Laser-Photofragmentation/Laser-Induced Fluorescence. Before any combustion activities, the mixing ratio of 3.0 ± 0.3 ppb is indicative of secondary sources such as multiphase formation from NO2. Cooking (with propane gas), especially the use of an oven, led to significant enhancements up to 84 ppb, with elevated mixing ratios persisting for a few days due to slow desorption from indoor surface reservoirs. Floor bleach cleaning led to prolonged, substantial decreases of up to 71-90% due to reactive processes. Air conditioning modulated HONO mixing ratios driven by condensation to wet surfaces in the AC unit. Enhanced ventilation also significantly lowered mixing ratios. Other conditions including human occupancy, ozone addition, and cleaning with terpene, natural product, and vinegar cleaners had a much smaller influence on HONO background levels measured following these activities.
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Schnitzler EG, Liu T, Hems RF, Abbatt JPD. Emerging investigator series: heterogeneous OH oxidation of primary brown carbon aerosol: effects of relative humidity and volatility. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:2162-2171. [PMID: 33020783 DOI: 10.1039/d0em00311e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The climate forcing of light-absorbing organic aerosol, or brown carbon (BrC), emitted from biomass burning may be significant but is currently poorly constrained, in part due to evolution during its residence time in the atmosphere. Here, the effects of ambient relative humidity (RH) and particle volatility on the heterogeneous OH oxidation of primary BrC were investigated in laboratory experiments. Particles were generated from smoldering pine wood, isolated from gaseous emissions, conditioned at 200 °C in a thermal denuder to remove the most volatile particulate organics, and injected into a smog chamber, where they were conditioned at either 15 or 60% RH and exposed to gas phase OH radicals. Changes in composition were monitored using an aerosol mass spectrometer (AMS), and changes in absorption at 405 nm were monitored using a photoacoustic spectrometer. Heterogeneous OH oxidation of nascent BrC at 60% RH resulted in steady increases in the AMS fraction of CO2+ (associated with carboxylic acids), the O : C ratio, and the carbon oxidation state, consistent with extensive functionalization. These composition changes corresponded first to very rapid absorption enhancement and then bleaching. Net bleaching was observed after the equivalent of 10 h residence time in the atmosphere. The evolution did not depend strongly on RH, consistent with homogeneously well-mixed primary BrC even at 15% RH at room temperature. In contrast, the evolution did depend strongly on the pre-treatment of the particles, such that only bleaching occurred for particles treated at 200 °C. This suggests that lower volatility constituents of ambient primary BrC have less capacity for absorption enhancement in the atmosphere upon heterogeneous oxidation, potentially as they are already more functionalized and/or oligomeric.
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Mattila JM, Lakey PSJ, Shiraiwa M, Wang C, Abbatt JPD, Arata C, Goldstein AH, Ampollini L, Katz EF, DeCarlo PF, Zhou S, Kahan TF, Cardoso-Saldaña FJ, Ruiz LH, Abeleira A, Boedicker EK, Vance ME, Farmer DK. Multiphase Chemistry Controls Inorganic Chlorinated and Nitrogenated Compounds in Indoor Air during Bleach Cleaning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:1730-1739. [PMID: 31940195 DOI: 10.1021/acs.est.9b05767] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
We report elevated levels of gaseous inorganic chlorinated and nitrogenated compounds in indoor air while cleaning with a commercial bleach solution during the House Observations of Microbial and Environmental Chemistry field campaign in summer 2018. Hypochlorous acid (HOCl), chlorine (Cl2), and nitryl chloride (ClNO2) reached part-per-billion by volume levels indoors during bleach cleaning-several orders of magnitude higher than typically measured in the outdoor atmosphere. Kinetic modeling revealed that multiphase chemistry plays a central role in controlling indoor chlorine and reactive nitrogen chemistry during these periods. Cl2 production occurred via heterogeneous reactions of HOCl on indoor surfaces. ClNO2 and chloramine (NH2Cl, NHCl2, NCl3) production occurred in the applied bleach via aqueous reactions involving nitrite (NO2-) and ammonia (NH3), respectively. Aqueous-phase and surface chemistry resulted in elevated levels of gas-phase nitrogen dioxide (NO2). We predict hydroxyl (OH) and chlorine (Cl) radical production during these periods (106 and 107 molecules cm-3 s-1, respectively) driven by HOCl and Cl2 photolysis. Ventilation and photolysis accounted for <50% and <0.1% total loss of bleach-related compounds from indoor air, respectively; we conclude that uptake to indoor surfaces is an important additional loss process. Indoor HOCl and nitrogen trichloride (NCl3) mixing ratios during bleach cleaning reported herein are likely detrimental to human health.
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Wang C, Collins DB, Arata C, Goldstein AH, Mattila JM, Farmer DK, Ampollini L, DeCarlo PF, Novoselac A, Vance ME, Nazaroff WW, Abbatt JPD. Surface reservoirs dominate dynamic gas-surface partitioning of many indoor air constituents. SCIENCE ADVANCES 2020; 6:eaay8973. [PMID: 32128415 PMCID: PMC7030931 DOI: 10.1126/sciadv.aay8973] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/22/2019] [Indexed: 05/21/2023]
Abstract
Human health is affected by indoor air quality. One distinctive aspect of the indoor environment is its very large surface area that acts as a poorly characterized sink and source of gas-phase chemicals. In this work, air-surface interactions of 19 common indoor air contaminants with diverse properties and sources were monitored in a house using fast-response, on-line mass spectrometric and spectroscopic methods. Enhanced-ventilation experiments demonstrate that most of the contaminants reside in the surface reservoirs and not, as expected, in the gas phase. They participate in rapid air-surface partitioning that is much faster than air exchange. Phase distribution calculations are consistent with the observations when assuming simultaneous equilibria between air and large weakly polar and polar absorptive surface reservoirs, with acid-base dissociation in the polar reservoir. Chemical exposure assessments must account for the finding that contaminants that are fully volatile under outdoor air conditions instead behave as semivolatile compounds indoors.
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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: 69] [Impact Index Per Article: 17.3] [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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Zhou Z, Zhou S, Abbatt JPD. Kinetics and Condensed-Phase Products in Multiphase Ozonolysis of an Unsaturated Triglyceride. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:12467-12475. [PMID: 31600435 DOI: 10.1021/acs.est.9b04460] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Ozone is an important oxidant in the environment. To study the nature of multiphase ozonolysis, an unsaturated triglyceride, triolein, of the type present in skin oil, biological membranes, and most cooking oils was oxidized by gas-phase ozone on a surface. A high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC-ESI-MS) method was developed for analyzing triolein and its oxidized products. Upon exposure to ozone, the decay of thin coatings of triolein was observed, accompanied by the formation of functionalized condensed-phase products including secondary ozonides (SOZ), acids, and aldehydes. By studying the reaction kinetics as a function of average coating thickness and ozone mixing ratio, we determined that the reactive uptake coefficient (γ) is on the order of 10-6 to 10-5. It is also concluded that the reaction occurs in the bulk without a major interfacial component, and the reacto-diffusive depth of ozone in the triolein coating is estimated to be between 8 and 40 nm. The specific nature of the reaction products is affected by the reactions of the Criegee intermediate formed during ozonolysis. In particular, although an increase in the relative humidity to 50% from dry conditions has no effect on the kinetics of triolein decay, the yield of SOZs is significantly depressed, indicating reactions of the Criegee intermediates to form hydroperoxides. Once formed, the SOZ products are thermally stable over periods of at least 48 h at room temperature but decomposition was observed under simulated outdoor sunlight, likely forming organic acids. From an environmental perspective, this chemistry indicates that SOZs and other oxygenates will form via ozonolysis of oily indoor surfaces and skin oil.
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Wang C, Collins DB, Abbatt JPD. Indoor Illumination of Terpenes and Bleach Emissions Leads to Particle Formation and Growth. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:11792-11800. [PMID: 31576741 DOI: 10.1021/acs.est.9b04261] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Application of chlorine bleach solution (major component sodium hypochlorite, NaOCl) in indoor environments leads to the emission of gaseous hypochlorous acid (HOCl) and chlorine (Cl2), both of which are strong oxidants. In contrast to the outdoor atmosphere, where mixing ratios of HOCl and Cl2 tend to be low (10s-100s of ppt), indoor HOCl and Cl2 can reach high levels during cleaning activities (100s of ppb or higher). HOCl and Cl2 may react with unsaturated organic compounds on indoor surfaces and in indoor air. In this study, we studied the reaction of limonene, one of the most common indoor volatile organic compounds (VOCs) arising from use of cleaning products, fragrance, and air fresheners, with HOCl and Cl2 in an environmental chamber. A dark reaction was observed between limonene and HOCl/Cl2 leading to gas-phase reaction products that were investigated using proton transfer reaction mass spectrometry (PTR-MS). With subsequent exposure to indoor fluorescent lights or diffuse sunlight through a nearby window, a substantial mass loading of secondary particles were formed with an averaged mass yield of 40% relative to the amount of limonene consumed. Aerosol mass spectrometry (AMS) measurements indicate a large contribution of particulate chlorine species. Electrospray ionization mass spectrometry (ESI-MS) analysis of filter-collected particles indicates the formation of high molecular weight products. This is the first study of the oxidation of limonene with HOCl and Cl2, and it illustrates the potential for particle formation to occur with indoor lighting during the use of common cleaning products.
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Wang S, Zhou S, Tao Y, Tsui WG, Ye J, Yu JZ, Murphy JG, McNeill VF, Abbatt JPD, Chan AWH. Organic Peroxides and Sulfur Dioxide in Aerosol: Source of Particulate Sulfate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:10695-10704. [PMID: 31418552 DOI: 10.1021/acs.est.9b02591] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Sulfur oxides (SOx) are important atmospheric trace species in both gas and particulate phases, and sulfate is a major component of atmospheric aerosol. One potentially important source of particulate sulfate formation is the oxidation of dissolved SO2 by organic peroxides, which comprises a major fraction of secondary organic aerosol (SOA). In this study, we investigated the reaction kinetics and mechanisms between SO2 and condensed-phase peroxides. pH-dependent aqueous phase reaction rate constants between S(IV) and organic peroxide standards were measured. Highly oxygenated organic peroxides with O/C > 0.6 in α-pinene SOA react rapidly with S(IV) species in the aqueous phase. The reactions between organic peroxides and S(IV) yield both inorganic sulfate and organosulfates (OS), as observed by electrospray ionization ion mobility mass spectrometry. For the first time, 34S-labeling experiments in this study revealed that dissolved SO2 forms OS via direct reactions without forming inorganic sulfate as a reactive intermediate. Kinetics of OS formation was estimated semiquantitatively, and such reaction was found to account for 30-60% of sulfur reacted. The photochemical box model GAMMA was applied to assess the implications of the measured SO2 consumption and OS formation rates. Our findings indicate that this novel pathway of SO2-peroxide reaction is important for sulfate formation in submicron aerosol.
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Hems RF, Wang C, Collins DB, Zhou S, Borduas-Dedekind N, Siegel JA, Abbatt JPD. Sources of isocyanic acid (HNCO) indoors: a focus on cigarette smoke. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1334-1341. [PMID: 30976776 DOI: 10.1039/c9em00107g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The sources and sinks of isocyanic acid (HNCO), a toxic gas, in indoor environments are largely uncharacterized. In particular, cigarette smoke has been identified as a significant source. In this study, controlled smoking of tobacco cigarettes was investigated in both an environmental chamber and a residence in Toronto, Canada using an acetate-CIMS. The HNCO emission ratio from side-stream cigarette smoke was determined to be 2.7 (±1.1) × 10-3 ppb HNCO/ppb CO. Side-stream smoke from a single cigarette introduced a large pulse of HNCO to the indoor environment, increasing the HNCO mixing ratio by up to a factor of ten from background conditions of 0.15 ppb. Although there was no evidence for photochemical production of HNCO from cigarette smoke in the residence, it was observed in the environmental chamber via oxidation by the hydroxyl radical (1.1 × 107 molecules per cm3), approximately doubling the HNCO mixing ratio after 30 minutes of oxidation. Oxidation of cigarette smoke by O3 (15 ppb = 4.0 × 1017 molecules per cm3) and photo-reaction with indoor fluorescent lights did not produce HNCO. By studying the temporal profiles of both HNCO and CO after smoking, it is inferred that gas-to-surface partitioning of HNCO acts as an indoor loss pathway. Even in the absence of smoking, the indoor HNCO mixing ratios in the Toronto residence were elevated compared to concurrent outdoor measurements by approximately a factor of two.
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Farmer DK, Vance ME, Abbatt JPD, Abeleira A, Alves MR, Arata C, Boedicker E, Bourne S, Cardoso-Saldaña F, Corsi R, DeCarlo PF, Goldstein AH, Grassian VH, Hildebrandt Ruiz L, Jimenez JL, Kahan TF, Katz EF, Mattila JM, Nazaroff WW, Novoselac A, O'Brien RE, Or VW, Patel S, Sankhyan S, Stevens PS, Tian Y, Wade M, Wang C, Zhou S, Zhou Y. Overview of HOMEChem: House Observations of Microbial and Environmental Chemistry. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2019; 21:1280-1300. [PMID: 31328749 DOI: 10.1039/c9em00228f] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The House Observations of Microbial and Environmental Chemistry (HOMEChem) study is a collaborative field investigation designed to probe how everyday activities influence the emissions, chemical transformations and removal of trace gases and particles in indoor air. Sequential and layered experiments in a research house included cooking, cleaning, variable occupancy, and window-opening. This paper describes the overall design of HOMEChem and presents preliminary case studies investigating the concentrations of reactive trace gases, aerosol particles, and surface films. Cooking was a large source of VOCs, CO2, NOx, and particles. By number, cooking particles were predominantly in the ultrafine mode. Organic aerosol dominated the submicron mass, and, while variable between meals and throughout the cooking process, was dominated by components of hydrocarbon character and low oxygen content, similar to cooking oil. Air exchange in the house ensured that cooking particles were present for only short periods. During unoccupied background intervals, particle concentrations were lower indoors than outdoors. The cooling coils of the house ventilation system induced cyclic changes in water soluble gases. Even during unoccupied periods, concentrations of many organic trace gases were higher indoors than outdoors, consistent with housing materials being potential sources of these compounds to the outdoor environment. Organic material accumulated on indoor surfaces, and exhibited chemical signatures similar to indoor organic aerosol.
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Faust JA, Abbatt JPD. Organic Surfactants Protect Dissolved Aerosol Components against Heterogeneous Oxidation. J Phys Chem A 2019; 123:2114-2124. [DOI: 10.1021/acs.jpca.9b00167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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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: 29] [Impact Index Per Article: 5.8] [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.
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Collins DB, Wang C, Abbatt JPD. Selective Uptake of Third-Hand Tobacco Smoke Components to Inorganic and Organic Aerosol Particles. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:13195-13201. [PMID: 30347142 DOI: 10.1021/acs.est.8b03880] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Third-hand smoke (THS) is an emerging route of exposure to tobacco smoke in the indoor environment. Few studies have investigated the chemical behavior of THS, although initial findings suggest that semivolatile components of THS can partition to indoor aerosol. By exposing single-component particles to THS in an environmental chamber, this study demonstrates a pronounced dependence of THS uptake on aerosol composition. First, it was found that primarily reduced nitrogen compounds (that produced C xH yN z+ ion signal) in THS partitioned strongly to acidic ammoniated sulfate particles, whereas overall THS uptake to more pH-neutral sodium sulfate particles was minimal. Second, THS uptake to pure hydrocarbon particles (squalane) was even greater than to ammoniated sulfate particles with the uptake arising from mainly C xH y compounds. The greater uptake of THS to squalane was mostly driven by the dominant fraction of C xH y compounds in the side stream cigarette smoke aerosol, the composition of which is likely to be broadly similar to THS in these experiments. Third, oxygenated organic particles (sucrose) and solid ammonium sulfate particles showed minimal uptake. These results indicate that particulate THS inhalation exposure will be strongly dependent on the chemical nature of the particles present in the indoor environment.
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Collins DB, Hems RF, Zhou S, Wang C, Grignon E, Alavy M, Siegel JA, Abbatt JPD. Evidence for Gas-Surface Equilibrium Control of Indoor Nitrous Acid. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:12419-12427. [PMID: 30346749 DOI: 10.1021/acs.est.8b04512] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Nitrous acid (HONO) is an important component of indoor air as a photolabile precursor to hydroxyl radicals and has direct health effects. HONO concentrations are typically higher indoors than outdoors, although indoor concentrations have proved challenging to predict using box models. In this study, time-resolved measurements of HONO and NO2 in a residence showed that [HONO] varied relatively weakly over contiguous periods of hours, while [NO2] fluctuated in association with changes in outdoor [NO2]. Perturbation experiments were performed in which indoor HONO was depleted or elevated and were interpreted using a two-compartment box model. To reproduce the measurements, [HONO] had to be predicted using persistent source and sink processes that do not directly involve NO2, suggesting that HONO was in equilibrium with indoor surfaces. Production of gas phase HONO directly from conversion of NO2 on surfaces had a weak influence on indoor [HONO] during the time of the perturbations. Highly similar temporal responses of HONO and semivolatile carboxylic acids to ventilation of the residence along with the detection of nitrite on indoor surfaces support the concept that indoor HONO mixing ratios are controlled strongly by gas-surface equilibrium.
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Alwarda R, Zhou S, Abbatt JPD. Heterogeneous oxidation of indoor surfaces by gas-phase hydroxyl radicals. INDOOR AIR 2018; 28:655-664. [PMID: 29873111 DOI: 10.1111/ina.12476] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/02/2018] [Indexed: 06/08/2023]
Abstract
We investigate heterogeneous oxidation kinetics of monolayer-thick, surface-sorbed organics, namely di-n-octyl phthalate (DnOP) and palmitic acid (PA), with gas-phase OH. The pseudo-first order rate constants for organic loss at OH concentrations of 1.6 × 108 molecules/cm3 are: (2.3 ± 0.1) × 10-4 to (4.8 ± 0.8) × 10-4 s-1 , and (1.3 ± 0.5) × 10-4 s-1 for DnOP and PA, respectively. Films developed in indoor office environments over a few weeks are also oxidized using the same OH concentration. Heterogeneous decay rate constants of mass signals from these films, attributed to phthalates (MW = 390.6) and to PA, are similar to those for the single-component films, ie, (1.9 ± 0.4) × 10-4 to (3.4 ± 0.5) × 10-4 s-1 , and (1.1 ± 0.4) × 10-4 s-1 , respectively. These results suggest that the lifetimes for OH heterogeneous oxidation of monolayer-thick indoor organic films will be on the timescale of weeks to months. To support this argument, we present the first analysis of the mass transfer processes that occur when short-lived gas-phase molecules, such as OH, are taken up by reactive indoor surfaces. Due to rapid chemical production, the diffusion limitation to mass transfer is less important for short-lived molecules than for molecules with little chemical production, such as ozone.
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