ACS ES&T Air最新文献

{"title":"Downdrafts of Biomass Burning to Houston Enhanced by Local Convective Activity","authors":"Rebecca J. Sheesley*,&nbsp;Mackenzie T. S. Ramirez,&nbsp;Jeewan Poudel,&nbsp;Travis Griggs,&nbsp;Manisha Mehra,&nbsp;Sujan Shrestha,&nbsp;Yang Li,&nbsp;Lucas Senkbeil and James Flynn,&nbsp;","doi":"10.1021/acsestair.4c0023210.1021/acsestair.4c00232","DOIUrl":"https://doi.org/10.1021/acsestair.4c00232https://doi.org/10.1021/acsestair.4c00232","url":null,"abstract":"<p >In June 2023, an elevated smoke layer from record-breaking Canadian wildfires was transported across the eastern half of the United States, impacting air quality for millions of people. Houston, TX experienced a notable biomass burning (BB) event associated with this wildfire smoke from Jun 4 to 9, 2023. The vertical transport of this smoke layer down to the surface followed afternoon convective activity in the Houston urban area on Jun 6–8. Our monitoring sites at urban, rural, and coastal locations around Houston experienced different levels of wildfire smoke. Carbon monoxide, aerosol absorption, and the Absorption Ångström Exponent (AAE) revealed stronger smoke incursions overnight at the urban site. The average nighttime AAE during the BB event period was 1.28 with 384 ppbv of CO; by comparison, the monthly nighttime averages for Jun 2023 were 1.03 and 172 ppbv, respectively. Enhanced PM_2.5 and NO₂ coincided with BB tracers while higher ozone concentrations were observed the following day at downwind sites relative to the peak observed BB smoke sites. The nighttime NO₂ for the BB event was also significantly higher than the monthly average with standard deviation for Jun 2023 (14.5 ppbv versus 5.19 ± 4.61 ppbv, respectively). Ozone concentrations peaked over 100 ppbv on Jun 9 driven by clear skies after the overnight high BB. Understanding the role of convective activity in enhancing the downdraft of BB plumes to the surface will improve assessment of the long-range impacts of wildfire smoke on urban populations.</p><p >Smoke from the June 2023 wildfires in Eastern Canada was transported at elevated layers to Houston, TX. Afternoon storms enhanced the downward mixing of this smoke to surface monitors.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"486–497 486–497"},"PeriodicalIF":0.0,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Wildfire Smoke PM2.5 on Indoor Air Quality of Public Buildings on a University Campus.","authors":"Rowshon Afroz, Jarred Alonzo, Sohaib Omar, Chu-Wen Cheng, Stephanie R Schneider, Ran Zhao","doi":"10.1021/acsestair.4c00342","DOIUrl":"https://doi.org/10.1021/acsestair.4c00342","url":null,"abstract":"<p><p>With increasing wildfire events impacting many regions worldwide, understanding and mitigating the effects of wildfire smoke on indoor air quality (IAQ) in public buildings are essential for protecting occupant health. This study investigated the impact of wildfire smoke on the IAQ across 24 campus buildings in Alberta, Canada, representing public spaces with varied ventilation systems. Using a network of low-cost sensors to monitor indoor PM_2.5, the study identified significant spikes during wildfire smoke events, with 71% of buildings exceeding the Canadian Ambient Air Quality Standards daily limit of 27 μg/m³. The buildings had mechanical ventilation systems with filters with different Minimum Efficiency Reporting Value (MERV) ratings. MERV13 filters were found to be more efficient at capturing PM_2.5 particles, resulting in lower indoor/outdoor PM_2.5 ratios (0.12 ± 0.07) compared to MERV8 filters (0.28 ± 0.14). Buildings with air change rates (ACH) ranging from 5 to 15 per hour exhibited different infiltration patterns, with higher ACH generally leading to elevated indoor PM_2.5 concentrations during wildfire events. This highlights the need to balance ventilation and pollutant infiltration by optimizing ACH rates and filtration efficiency to reduce indoor PM_2.5. The trajectory-fire interception method, combined with satellite data, enhanced the identification of wildfire-influenced periods, contributing to a better understanding of smoke infiltration dynamics. These findings underscore that even advanced filtration and ventilation systems alone may not ensure a healthy IAQ during extreme pollution. Real-time pollutant measurements are crucial for effective IAQ management. The findings offer valuable insights for building administrators and policymakers, helping them develop strategies to mitigate the effects of wildfire smoke and to support healthier indoor environments during wildfire seasons.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"625-636"},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11998926/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144030693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Wildfire Smoke PM2.5 on Indoor Air Quality of Public Buildings on a University Campus","authors":"Rowshon Afroz,&nbsp;Jarred Alonzo,&nbsp;Sohaib Omar,&nbsp;Chu-Wen Cheng,&nbsp;Stephanie R. Schneider and Ran Zhao*,&nbsp;","doi":"10.1021/acsestair.4c0034210.1021/acsestair.4c00342","DOIUrl":"https://doi.org/10.1021/acsestair.4c00342https://doi.org/10.1021/acsestair.4c00342","url":null,"abstract":"<p >With increasing wildfire events impacting many regions worldwide, understanding and mitigating the effects of wildfire smoke on indoor air quality (IAQ) in public buildings are essential for protecting occupant health. This study investigated the impact of wildfire smoke on the IAQ across 24 campus buildings in Alberta, Canada, representing public spaces with varied ventilation systems. Using a network of low-cost sensors to monitor indoor PM_2.5, the study identified significant spikes during wildfire smoke events, with 71% of buildings exceeding the Canadian Ambient Air Quality Standards daily limit of 27 μg/m³. The buildings had mechanical ventilation systems with filters with different Minimum Efficiency Reporting Value (MERV) ratings. MERV13 filters were found to be more efficient at capturing PM_2.5 particles, resulting in lower indoor/outdoor PM_2.5 ratios (0.12 ± 0.07) compared to MERV8 filters (0.28 ± 0.14). Buildings with air change rates (ACH) ranging from 5 to 15 per hour exhibited different infiltration patterns, with higher ACH generally leading to elevated indoor PM_2.5 concentrations during wildfire events. This highlights the need to balance ventilation and pollutant infiltration by optimizing ACH rates and filtration efficiency to reduce indoor PM_2.5. The trajectory-fire interception method, combined with satellite data, enhanced the identification of wildfire-influenced periods, contributing to a better understanding of smoke infiltration dynamics. These findings underscore that even advanced filtration and ventilation systems alone may not ensure a healthy IAQ during extreme pollution. Real-time pollutant measurements are crucial for effective IAQ management. The findings offer valuable insights for building administrators and policymakers, helping them develop strategies to mitigate the effects of wildfire smoke and to support healthier indoor environments during wildfire seasons.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"625–636 625–636"},"PeriodicalIF":0.0,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical Composition of Fresh and Aged Asphalt-Related Organic Aerosols: From Ambient Observations to Laboratory Experiments","authors":"Peeyush Khare,&nbsp;Jo Machesky,&nbsp;Leah Williams,&nbsp;Mackenzie Humes,&nbsp;Edward C. Fortner,&nbsp;Manjula Canagaratna,&nbsp;Jordan E. Krechmer,&nbsp;Andrew T. Lambe,&nbsp;Albert A. Presto and Drew R. Gentner*,&nbsp;","doi":"10.1021/acsestair.4c0019310.1021/acsestair.4c00193","DOIUrl":"https://doi.org/10.1021/acsestair.4c00193https://doi.org/10.1021/acsestair.4c00193","url":null,"abstract":"<p >Asphalt-related emissions are an understudied source of reactive organic compounds with the potential to form organic aerosol (OA). Ambient aerosol mass spectrometry (AMS) measurements of asphalt-related aerosols near a month-long road paving project showed enhanced ambient OA concentrations with a mix of primary and secondary OA signatures. For comparison, gas-phase emissions from real-world road asphalt samples at application (e.g., 140 °C) and in-use (e.g., 60 °C) temperatures were injected into an environmental chamber and an oxidation flow reactor to simulate varying degrees of oxidative aging while measuring their gas- and aerosol-phase oxidation products. Secondary OA formation was observed via both self-nucleation and condensation, with chemical properties dependent on asphalt temperature and reaction conditions. The chemical composition of less-aged asphalt-related OA observed in outdoor and laboratory measurements was similar to OA from other petrochemical-based sources and hydrocarbon-like OA source factors observed via AMS in previous urban studies. The composition of aged OA varied with the degree of oxidation, similar to oxidized OA factors observed in ambient air. Taken together, these field and laboratory observations suggest that contributions to urban OA during and after application may be challenging to deconvolve from other traditional sources in ambient measurements.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"446–455 446–455"},"PeriodicalIF":0.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Burning Characteristics and Smoke Emission from Mixed Fuel Cribs","authors":"Aika Y. Davis*,&nbsp;Thomas G. Cleary,&nbsp;Ryan L. Falkenstein-Smith and Rodney A. Bryant,&nbsp;","doi":"10.1021/acsestair.4c0027510.1021/acsestair.4c00275","DOIUrl":"https://doi.org/10.1021/acsestair.4c00275https://doi.org/10.1021/acsestair.4c00275","url":null,"abstract":"<p >Experiments were conducted to study the burning characteristics and smoke emission from mixed fuel crib assemblies designed to represent the main components in structures. Cribs consisting of wood, drywall, and plastics were assembled into cubic structures, all with the same mass fraction for each material. Three packing densities and two crib sizes were studied. While a crib burned to completion, the smoke was collected in a fire calorimetry system for the heat release rate (HRR), combustion gases, and smoke measurements. The scale of cribs affected the burn duration and the total heat release, but the packing density had a greater effect on modified combustion efficiency, peak HRR, and the emission factors of CO₂, CO, formaldehyde, acrolein, SO₂, and total hydrocarbons. The variability in scale and packing density studied here can affect the structure fire emission estimates by 20% for CO₂ and smoke and up to 130% for SO₂ and formaldehyde. Therefore, packing density must be considered to properly evaluate structural fires.</p><p >Burning behavior and emission yields of mixed fuel fire found here could help quantify smoke production in wildland urban interface communities and aid in predicting smoke spread and deteriorating air quality downwind.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"540–547 540–547"},"PeriodicalIF":0.0,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsestair.4c00275","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Burning Characteristics and Smoke Emission from Mixed Fuel Cribs.","authors":"Aika Y Davis, Thomas G Cleary, Ryan L Falkenstein-Smith, Rodney A Bryant","doi":"10.1021/acsestair.4c00275","DOIUrl":"https://doi.org/10.1021/acsestair.4c00275","url":null,"abstract":"<p><p>Experiments were conducted to study the burning characteristics and smoke emission from mixed fuel crib assemblies designed to represent the main components in structures. Cribs consisting of wood, drywall, and plastics were assembled into cubic structures, all with the same mass fraction for each material. Three packing densities and two crib sizes were studied. While a crib burned to completion, the smoke was collected in a fire calorimetry system for the heat release rate (HRR), combustion gases, and smoke measurements. The scale of cribs affected the burn duration and the total heat release, but the packing density had a greater effect on modified combustion efficiency, peak HRR, and the emission factors of CO₂, CO, formaldehyde, acrolein, SO₂, and total hydrocarbons. The variability in scale and packing density studied here can affect the structure fire emission estimates by 20% for CO₂ and smoke and up to 130% for SO₂ and formaldehyde. Therefore, packing density must be considered to properly evaluate structural fires.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"540-547"},"PeriodicalIF":0.0,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11997947/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143996857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Collecting Airborne Organochlorines on Polyurethane Foam: Comparison of Field Observations with a Breakthrough Model","authors":"Terry F. Bidleman*,&nbsp;Fiona Wong,&nbsp;Helena Dryfhout-Clark,&nbsp;Hayley Hung* and Mats Tysklind,&nbsp;","doi":"10.1021/acsestair.4c0028110.1021/acsestair.4c00281","DOIUrl":"https://doi.org/10.1021/acsestair.4c00281https://doi.org/10.1021/acsestair.4c00281","url":null,"abstract":"<p >Polyurethane foam (PUF) is widely used for active air sampling (AAS) of gaseous semivolatile organic compounds (SVOCs). PUF efficiently collects SVOCs with moderate to low volatility, but applications are limited for the more volatile SVOCs due to breakthrough from the PUF trap. The collection efficiency can be predicted by frontal chromatography theory with knowledge of several parameters: the sampled air volume, the breakthrough volume which depends on the PUF/air partition ratio (<i>K</i>_<i>PA</i>), and the number of theoretical plates (<i>N</i>) in the PUF trap. Here we evaluate data from two Canadian air monitoring programs in which front and back PUF traps (P1 and P2) were used to check for breakthrough, as indicated by the back/front ratio (P2/P1) of collected SVOCs. A frontal chromatography model was used to relate collection efficiency of hexachlorobenzene (HCB) and α-hexachlorocyclohexane (α-HCH) to their observed P2/P1 ratios under assumed scenarios of <i>K</i>_<i>PA</i> and <i>N</i>, and apparent <i>N</i>-values for the PUF traps were derived. Results were applied to correcting observed air concentrations of HCB for breakthrough loss. The choice of <i>K</i>_<i>PA</i> greatly influenced the adjusted air concentrations and their variation with temperature.</p><p >Collection of airborne semivolatile organic compounds by polyurethane foam (PUF) was adjusted for breakthrough loss by frontal chromatography theory and field observations of penetration through PUF traps.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"548–556 548–556"},"PeriodicalIF":0.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsestair.4c00281","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sector-, Season-, and Country-Specific NO₂-Associated Health Benefits from NO _<i>x</i> Emission Reductions.","authors":"Patrick Wiecko, Daven K Henze, M Omar Nawaz","doi":"10.1021/acsestair.5c00012","DOIUrl":"https://doi.org/10.1021/acsestair.5c00012","url":null,"abstract":"<p><p>Long-term exposure to NO₂ is associated with elevated risks for pediatric asthma and premature death. Despite national policies targeting NO₂'s main source, NO _<i>x</i> emissions, its global health burden remains high. Here, we use the air quality model GEOS-Chem adjoint with TROPOspheric Monitoring Instrument (TROPOMI)-based satellite downscaling to estimate that long-term NO₂ exposure is responsible for 2.07 (95% CI 0.91-2.70) million pediatric asthma cases and 1.98 (95% CI 0.52-2.86) million deaths globally in 2019. We attribute these to anthropogenic NO _<i>x</i> emissions by sector, country, and season using the adjoint model and provide a recommendation for the most impactful sector and season for NO _<i>x</i> emission controls in each G20 country. Discrepancies exist between the health benefits incurred by emission reductions and the emission sector distributions, particularly in countries with emitters adjoining population centers. For example, we find that, if Russian anthropogenic NO _<i>x</i> emissions were reduced uniformly by 10% across all sectors, the energy sector, 31% of annual NO _<i>x</i> emissions, would account for 47% of pediatric asthma and 49% of premature death health benefits. The season in which these emission reductions occur also affects the magnitude of the health benefit, as seen by the fact that Russian wintertime NO _<i>x</i> emission reductions alone are responsible for approximately one-third of the annual health benefits for each health outcome. We present the unique results for each of the G20 members to showcase how a country's NO _<i>x</i> emission reductions can be most impactful in reducing the global NO₂-associated health burden.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"700-709"},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11997953/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143996858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemical and Cloud and Aerosol Aqueous Contributions to Regionally-Emitted Shipping and Biogenic Non-Sea-Salt Sulfate Aerosol in Coastal California.","authors":"Nattamon Maneenoi, Lynn M Russell, Sanghee Han, Jeramy L Dedrick, Abigail S Williams, Veronica Z Berta, Christian Pelayo, Maria A Zawadowicz, Arthur J Sedlacek, Israel Silber, Mandy Thieman, David Painemal, Samuel S P Shen","doi":"10.1021/acsestair.4c00352","DOIUrl":"https://doi.org/10.1021/acsestair.4c00352","url":null,"abstract":"<p><p>Aerosol nonsea-salt sulfate (NSS sulfate) forms in the atmosphere by secondary reactions of emissions from marine phytoplankton and shipping, with gas-phase as well as cloud and aerosol aqueous reactions controlling production. Twelve months of Atmospheric Radiation Measurements (ARM) during the Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE) at Scripps Pier in La Jolla, California, showed the highest NSS sulfate mass concentrations occurred for the northwesterly back-trajectories over 64% of the year, with an average of 0.90 μg/m³ that contributed 76% of annual NSS sulfate concentration. Multiple Linear Regression (MLR) and a refractory black carbon tracer method attributed 76-80% of the regionally emitted sulfur dioxide (SO₂) sources of submicron NSS sulfate to marine biogenic emissions and 20-24% to shipping emissions. MLR for oxidation processes explained 21% of the variability with Downwelling Shortwave Radiation (DSW) driving photochemical reactions to account for 34% of annual regional sulfate production, Upwind Cloud Vertical Fraction (UCVF) controlling cloud-associated oxidation to account for 29%, and relative humidity (RH) describing aerosol-phase oxidation to account for 36%. NSS sulfate was correlated moderately to UCVF during April-June and August but to RH in October-January. These findings show the apportionment of SO₂ emissions to biogenic and shipping sources and provide observational constraints for the mechanisms for sulfate production from SO₂ in the atmosphere.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"648-664"},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11997993/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144040565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemical and Cloud and Aerosol Aqueous Contributions to Regionally-Emitted Shipping and Biogenic Non-Sea-Salt Sulfate Aerosol in Coastal California","authors":"Nattamon Maneenoi,&nbsp;Lynn M. Russell*,&nbsp;Sanghee Han,&nbsp;Jeramy L. Dedrick,&nbsp;Abigail S. Williams,&nbsp;Veronica Z. Berta,&nbsp;Christian Pelayo,&nbsp;Maria A. Zawadowicz,&nbsp;Arthur J. Sedlacek III,&nbsp;Israel Silber,&nbsp;Mandy Thieman,&nbsp;David Painemal and Samuel S. P. Shen,&nbsp;","doi":"10.1021/acsestair.4c0035210.1021/acsestair.4c00352","DOIUrl":"https://doi.org/10.1021/acsestair.4c00352https://doi.org/10.1021/acsestair.4c00352","url":null,"abstract":"<p >Aerosol nonsea-salt sulfate (NSS sulfate) forms in the atmosphere by secondary reactions of emissions from marine phytoplankton and shipping, with gas-phase as well as cloud and aerosol aqueous reactions controlling production. Twelve months of Atmospheric Radiation Measurements (ARM) during the Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE) at Scripps Pier in La Jolla, California, showed the highest NSS sulfate mass concentrations occurred for the northwesterly back-trajectories over 64% of the year, with an average of 0.90 μg/m³ that contributed 76% of annual NSS sulfate concentration. Multiple Linear Regression (MLR) and a refractory black carbon tracer method attributed 76–80% of the regionally emitted sulfur dioxide (SO₂) sources of submicron NSS sulfate to marine biogenic emissions and 20–24% to shipping emissions. MLR for oxidation processes explained 21% of the variability with Downwelling Shortwave Radiation (DSW) driving photochemical reactions to account for 34% of annual regional sulfate production, Upwind Cloud Vertical Fraction (UCVF) controlling cloud-associated oxidation to account for 29%, and relative humidity (RH) describing aerosol-phase oxidation to account for 36%. NSS sulfate was correlated moderately to UCVF during April-June and August but to RH in October-January. These findings show the apportionment of SO₂ emissions to biogenic and shipping sources and provide observational constraints for the mechanisms for sulfate production from SO₂ in the atmosphere.</p><p >Aerosol sulfate in coastal regions has contributions from marine biogenic and shipping emissions, but atmospheric oxidation transforms the emitted gases to particles. The findings provide observational constraints on sulfate sources and cloud and aerosol processes, quantifying their impact on air quality and climate.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 4","pages":"648–664 648–664"},"PeriodicalIF":0.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsestair.4c00352","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143814521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}