ACS ES&T AirPub Date : 2025-02-28DOI: 10.1021/acsestair.4c0023710.1021/acsestair.4c00237
Arvind P. Ravikumar*, Hugh Li, Shuting Lydia Yang and Mackenzie L. Smith,
{"title":"Developing Measurement-Informed Methane Emissions Inventory Estimates at Midstream Compressor Stations","authors":"Arvind P. Ravikumar*, Hugh Li, Shuting Lydia Yang and Mackenzie L. Smith, ","doi":"10.1021/acsestair.4c0023710.1021/acsestair.4c00237","DOIUrl":"https://doi.org/10.1021/acsestair.4c00237https://doi.org/10.1021/acsestair.4c00237","url":null,"abstract":"<p >Natural gas transmissions and storage compressor stations account for the largest share of anthropogenic methane (CH<sub>4</sub>) emissions in New York State (NYS). Yet, NYS’s CH<sub>4</sub> emissions inventory is based on measurements that are a decade old and potentially unlikely to be representative of NYS operations. Here, we present results from a comprehensive, multiscale aerial CH<sub>4</sub> measurement campaign across all NYS transmission and storage compressor stations. We find a skewed emissions distribution, with 20% of stations accounting for 74% of total CH<sub>4</sub> emissions. Emissions at engine-driven compressor stations are, on average, 3–4× higher than emissions at turbine-driven compressor stations, thus demonstrating the need for separate emissions factors for engine- and turbine-drive compressor stations. Overall, measurement-informed emissions inventory from midstream transmission and storage compressor stations in NYS is 72% and 69% lower than the current NYS inventory, respectively. We estimate updated emissions factors of 464 [95% CI: 162–920] metric ton (MT) CH<sub>4</sub>/station/yr and 139 [97, 191] MT CH<sub>4</sub>/station/yr for engine- and turbine-based transmission compressor stations, respectively. Similarly, we estimate an updated emissions factor of 413 [164, 733] MT CH<sub>4</sub>/station/yr for engine-based storage compressor stations. These updated emissions factors, along with improved activity data, enable effective reconciliation of NYS inventory with measured emissions.</p><p >This study reports on the first large-scale measurement of methane emissions from midstream compressor stations in New York and provides a scalable approach to reconcile and update official emission inventories.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"358–367 358–367"},"PeriodicalIF":0.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsestair.4c00237","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608907","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}
ACS ES&T AirPub Date : 2025-02-27DOI: 10.1021/acsestair.4c0029410.1021/acsestair.4c00294
Colton T. Calvert, Nathan J. Huskins and Elijah G. Schnitzler*,
{"title":"Intermolecular Interactions Enhance the Light Absorption of a Methoxyphenol Constituent of Biomass Burning Emissions","authors":"Colton T. Calvert, Nathan J. Huskins and Elijah G. Schnitzler*, ","doi":"10.1021/acsestair.4c0029410.1021/acsestair.4c00294","DOIUrl":"https://doi.org/10.1021/acsestair.4c00294https://doi.org/10.1021/acsestair.4c00294","url":null,"abstract":"<p >Brown carbon (BrC) components of biomass burning organic aerosol (BBOA) absorb sunlight at visible wavelengths. However, it is not clear whether the total light absorption of this BrC is simply the sum of the contributions of the individual components or whether the components can bind noncovalently to give additional absorption through charge transfer. Here, intermolecular interactions between guaiacol and quinones (1,4-benzoquinone and 1,4-naphthoquinone) were identified in proxies of the nonpolar, water-insoluble phase of BBOA, using UV–vis spectroscopy. Guaiacol and its derivatives are some of the most abundant emissions of smoldering coniferous species. Enhanced light absorption occurred instantaneously upon mixing colorless guaiacol with either quinone in <i>n</i>-heptane and did not increase with time, in contrast to the absorbance changes that would be expected for a covalent product. This enhancement decreased by about 25% as the temperature increased from 303 to 323 K, consistent with exothermic association to give complexes, yielding enthalpies of complexation of −13.3 ± 0.6 and −12.3 ± 0.4 kJ mol<sup>–1</sup> for guaiacol with benzoquinone and naphthoquinone, respectively. Enhancement was also observed upon gas–liquid partitioning of benzoquinone into thin films of guaiacol, for example, with a thickness of 20 μm. This multiphase processing, mimicking partitioning of quinones into liquid BBOA, produced absorption comparable to moderately absorbing BrC from other sources, suggestive of the atmospheric relevance of these interactions.</p><p >Colorless guaiacol absorbs visible light when complexed with benzoquinone and naphthoquinone, so it is a potential component of brown carbon in biomass burning emissions.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"406–415 406–415"},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsestair.4c00294","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608959","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}
ACS ES&T AirPub Date : 2025-02-27eCollection Date: 2025-03-14DOI: 10.1021/acsestair.4c00294
Colton T Calvert, Nathan J Huskins, Elijah G Schnitzler
{"title":"Intermolecular Interactions Enhance the Light Absorption of a Methoxyphenol Constituent of Biomass Burning Emissions.","authors":"Colton T Calvert, Nathan J Huskins, Elijah G Schnitzler","doi":"10.1021/acsestair.4c00294","DOIUrl":"10.1021/acsestair.4c00294","url":null,"abstract":"<p><p>Brown carbon (BrC) components of biomass burning organic aerosol (BBOA) absorb sunlight at visible wavelengths. However, it is not clear whether the total light absorption of this BrC is simply the sum of the contributions of the individual components or whether the components can bind noncovalently to give additional absorption through charge transfer. Here, intermolecular interactions between guaiacol and quinones (1,4-benzoquinone and 1,4-naphthoquinone) were identified in proxies of the nonpolar, water-insoluble phase of BBOA, using UV-vis spectroscopy. Guaiacol and its derivatives are some of the most abundant emissions of smoldering coniferous species. Enhanced light absorption occurred instantaneously upon mixing colorless guaiacol with either quinone in <i>n</i>-heptane and did not increase with time, in contrast to the absorbance changes that would be expected for a covalent product. This enhancement decreased by about 25% as the temperature increased from 303 to 323 K, consistent with exothermic association to give complexes, yielding enthalpies of complexation of -13.3 ± 0.6 and -12.3 ± 0.4 kJ mol<sup>-1</sup> for guaiacol with benzoquinone and naphthoquinone, respectively. Enhancement was also observed upon gas-liquid partitioning of benzoquinone into thin films of guaiacol, for example, with a thickness of 20 μm. This multiphase processing, mimicking partitioning of quinones into liquid BBOA, produced absorption comparable to moderately absorbing BrC from other sources, suggestive of the atmospheric relevance of these interactions.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"406-415"},"PeriodicalIF":0.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11915197/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143665792","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}
ACS ES&T AirPub Date : 2025-02-20DOI: 10.1021/acsestair.4c0024710.1021/acsestair.4c00247
Katherine M. Ratliff*, Lukas Oudejans, M. Worth Calfee, John Archer, Jerome U. Gilberry, David Adam Hook, William E. Schoppman and Robert W. Yaga,
{"title":"Factors Affecting Reduction of Infectious Aerosols by Far-UVC and Portable HEPA Air Cleaners","authors":"Katherine M. Ratliff*, Lukas Oudejans, M. Worth Calfee, John Archer, Jerome U. Gilberry, David Adam Hook, William E. Schoppman and Robert W. Yaga, ","doi":"10.1021/acsestair.4c0024710.1021/acsestair.4c00247","DOIUrl":"https://doi.org/10.1021/acsestair.4c00247https://doi.org/10.1021/acsestair.4c00247","url":null,"abstract":"<p >Technologies that can reduce concentrations of airborne microorganisms through either particle capture or inactivation are important tools for reducing the risk of disease transmission and improving overall indoor air quality. The effectiveness of these technologies is tested in different ways, and as a result, it is challenging to compare results and optimize their use in applied settings. In this study, experiments were conducted in a large bioaerosol chamber to evaluate the efficacy of far-UVC and portable HEPA air cleaners against the bacteriophage MS2 as a surrogate for human viral pathogens. For both technologies, changing the media used to aerosolize the microorganism from deionized water to a simulated saliva doubled effectiveness metrics (both log<sub>10</sub> reductions and clean air delivery rates). Because reductions did not follow first order, log–linear dynamics, using different segments of the test period to calculate efficacy also significantly impacted reported performance. Evidence shown here indicates that both microbiological and particle dynamics likely play a role in impacting test outcomes under current methods, and more research is needed to improve repeatable and reliable standardized approaches for determining technology performance against infectious aerosols.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"368–377 368–377"},"PeriodicalIF":0.0,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609114","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}
ACS ES&T AirPub Date : 2025-02-18DOI: 10.1021/acsestair.4c0028210.1021/acsestair.4c00282
Yaxi Liu, Jianhuai Ye*, Yan Yang, Chen Yu, Fan Yang, Bi Chen, Jianguo Zhou, Gan Yang, Xinning Wang, Xiaohui Lu, Jianmin Chen, Zimeng Wang, Lin Wang, Xiaofei Wang* and Xin Yang*,
{"title":"Volatile Organic Compound Emissions from Polluted and Natural Soils: Influences of Environmental Factors","authors":"Yaxi Liu, Jianhuai Ye*, Yan Yang, Chen Yu, Fan Yang, Bi Chen, Jianguo Zhou, Gan Yang, Xinning Wang, Xiaohui Lu, Jianmin Chen, Zimeng Wang, Lin Wang, Xiaofei Wang* and Xin Yang*, ","doi":"10.1021/acsestair.4c0028210.1021/acsestair.4c00282","DOIUrl":"https://doi.org/10.1021/acsestair.4c00282https://doi.org/10.1021/acsestair.4c00282","url":null,"abstract":"<p >Volatile organic compounds (VOCs) impact urban air quality and human health. Soil represents a potentially important source of VOCs. However, the VOC emission characteristics of soils from different urban and natural environments remain unclear. In this study, the composition and flux of VOCs emitted from various soil types were examined. Results reveal significantly elevated VOC emissions from polluted soils, with levels 2 orders of magnitude higher than those from their natural counterparts. Influences of light, soil water content, and temperature on VOC emissions were explored. Light exposure notably enhanced the emissions of certain VOCs, such as acetonitrile, from highly polluted industrial soils. Simultaneously, reductions in VOCs such as terpenes were observed, possibly driven by photochemical degradation processes. By comparison, soils from less polluted environments exhibited minimal changes in VOC emissions under light exposure, emphasizing the distinct behaviors of different soil types. Soil water content was inversely correlated with VOC emission rates, likely due to reduced soil porosity and permeability at higher moisture levels, whereas temperature exhibited intricate effects on soil emissions that varied with VOC species. Factors such as soil VOC storage, VOC “affinity” to soil, and microbial activities may play roles and warrant future investigation. Results from this study highlight soil emissions as non-negligible contributors to ambient VOC levels and underscore the crucial impacts of environmental factors in modulating these emissions.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"386–395 386–395"},"PeriodicalIF":0.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609040","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}
ACS ES&T AirPub Date : 2025-02-17DOI: 10.1021/acsestair.4c0032310.1021/acsestair.4c00323
Anais Lostier, Thibaud Sarica, Jerome Lasne, Antoine Roose, Karine Sartelet, Marina Jamar, Vincent Gaudion, Sebastien Dusanter, Didier Lesueur, Hui Chen, Therese Salameh* and Manolis N. Romanias*,
{"title":"Real-World Asphalt Pavement Emissions: Combining Simulation Chamber Measurements and City Scale Modeling to Elucidate the Impacts on Air Quality","authors":"Anais Lostier, Thibaud Sarica, Jerome Lasne, Antoine Roose, Karine Sartelet, Marina Jamar, Vincent Gaudion, Sebastien Dusanter, Didier Lesueur, Hui Chen, Therese Salameh* and Manolis N. Romanias*, ","doi":"10.1021/acsestair.4c0032310.1021/acsestair.4c00323","DOIUrl":"https://doi.org/10.1021/acsestair.4c00323https://doi.org/10.1021/acsestair.4c00323","url":null,"abstract":"<p >In this paper, the role of asphalt pavement emissions in urban air quality was assessed combining laboratory experiments and city-scale air-quality modeling. In particular, the emission factors (EFs) of volatile and intermediate volatility organic compounds (VOCs and IVOCs) of asphalt pavements were determined in an atmospheric simulation chamber. Relative humidity (RH) and simulated solar light UV-A radiation were found to play a key role in the emission of VOCs and IVOCs. RH significantly increased the EFs, and predominantly those of oxygenated VOCs, due to changes in the microphysical properties of the materials. Under UV-A radiation, EFs were enhanced, due to the photochemical process induced on the asphalt–air interface. IVOCs were found to account for up to 30% of the Total EFs measured. Considering Paris as a case study, asphalt emissions in air-quality simulations lead to an increase in organic aerosol concentrations of at least 3%, during average summer daytime conditions. We estimate this impact significantly higher, in case all the IVOCs emissions are included in the model. This highlights the significant influence of solar radiation on emissions from old asphalt when exposed to UV radiation and the impact on air quality during the summer.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"426–435 426–435"},"PeriodicalIF":0.0,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609013","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}
ACS ES&T AirPub Date : 2025-02-13DOI: 10.1021/acsestair.4c0016910.1021/acsestair.4c00169
Justin G. Coughlin*, Antonios Tasoglou, Katherine Haile, Leslie P. Silva, Scott Hamilton, Marta Fuoco, Samuel Porter, Aikaterini Liangou and Eben Thoma,
{"title":"Comparing Short-Term Volatile Organic Compound Measurements in Fenceline Environments Using Multiple Mobile Air Monitoring Platforms and Methods","authors":"Justin G. Coughlin*, Antonios Tasoglou, Katherine Haile, Leslie P. Silva, Scott Hamilton, Marta Fuoco, Samuel Porter, Aikaterini Liangou and Eben Thoma, ","doi":"10.1021/acsestair.4c0016910.1021/acsestair.4c00169","DOIUrl":"https://doi.org/10.1021/acsestair.4c00169https://doi.org/10.1021/acsestair.4c00169","url":null,"abstract":"<p >The presence of volatile organic compounds (VOCs) can increase the air pollution burden in fenceline communities. Technological advancements have made mobile air toxic monitoring a useful and attractive approach to spatially quantify VOC concentrations in real-time, but there is a need to evaluate the accuracy of these measurements in real-world applications using intercomparison techniques. Here, we conducted a two-week field campaign near different VOC-emitting facilities using three different mobile monitoring platforms and four different ambient VOC-measurement technologies. Our primary focus was the intercomparison of a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) and canister samples analyzed by an offline gas chromatograph mass spectrometer (GC-MS), but we also collected measurements using a closed-path ultraviolet differential optical absorption spectrometer (UV-DOAS) and a selected ion flow tube mass spectrometer (SIFT-MS). The PTR-ToF-MS and offline GC-MS analyses show strong agreement in stationary settings (all targeted VOCs <i>R</i><sup>2</sup> = 0.92, slope = 1.1) for aromatic compounds including benzene (<i>R</i><sup>2</sup> = 0.95, <i>p</i> < 0.001), naphthalene (<i>R</i><sup>2</sup> = 0.84, <i>p</i> < 0.01), and xylenes + ethylbenzene (<i>R</i><sup>2</sup> = 0.93, <i>p</i> < 0.01). PTR-ToF-MS and UV-DOAS comparisons have varied results. The UV-DOAS compared well at some monitoring locations but had poor agreement in ambient air matrices containing naphthalene, which caused uncorrectable interferences for measurements of benzene, toluene, and xylenes. Lastly, the PTR-ToF-MS and SIFT-MS showed strong agreement (all targeted VOCs <i>R</i><sup>2</sup> = 0.68, slope = 0.85) in mobile format comparisons but only when aldehyde compounds with high background noise were removed. Our results highlight some potential interferences that should be accounted for when performing monitoring of mobile air toxics and demonstrate multi-instrument comparison techniques that can be used to ensure robust data collection.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"295–308 295–308"},"PeriodicalIF":0.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608879","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}
ACS ES&T AirPub Date : 2025-02-12DOI: 10.1021/acsestair.4c0021910.1021/acsestair.4c00219
Stephanie E. Cleland*, Naman Paul, Eric S. Coker and Sarah B. Henderson,
{"title":"The Co-occurrence of Wildfire Smoke and Extreme Heat Events in British Columbia, 2010–2022: Evaluating Spatiotemporal Trends and Inequities in Exposure Burden","authors":"Stephanie E. Cleland*, Naman Paul, Eric S. Coker and Sarah B. Henderson, ","doi":"10.1021/acsestair.4c0021910.1021/acsestair.4c00219","DOIUrl":"https://doi.org/10.1021/acsestair.4c00219https://doi.org/10.1021/acsestair.4c00219","url":null,"abstract":"<p >Climate change is fueling more frequent and severe wildfire smoke (WFS) and extreme heat events (EHEs), and co-exposure may have synergistic adverse health effects. We evaluated the spatiotemporal trends in population exposure to co-occurring WFS and EHEs (WFS-EHEs) in British Columbia (BC). We calculated the frequency, intensity, and trends in WFS-EHEs in each census dissemination area (DA) in BC between 2010 and 2022. WFS-EHEs were identified using established exceedance thresholds and daily data on fine particulate matter, smoke plumes, and meteorological conditions. Trends were identified using the Mann–Kendall and Theil–Sen approaches. Census data was used to identify the characteristics of the most exposed communities. Over 13 years, there were 276,666 DA-level WFS-EHEs, impacting all BC residents and leading to a cumulative 170.8 million person-days of exposure. Although there was substantial year-to-year variability, the frequency and intensity of WFS-EHEs increased over time, with 60.8% of co-occurrences between 2018 and 2022. 42.5% of DAs (∼1.9 million people) experienced significant increases in exposure. The highest co-exposure burden occurred in rural communities with lower adaptive capacity. Our findings demonstrate the need for public health guidance on these increasingly frequent and intense compound hazards and can inform climate change adaptation and mitigation efforts in BC and elsewhere.</p><p >Wildfire smoke and extreme heat are increasing with climate change, but it is unknown how often these health-damaging exposures co-occur in British Columbia. We identify highly exposed communities and changes in co-exposure burden over time.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"319–330 319–330"},"PeriodicalIF":0.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsestair.4c00219","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608851","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}
ACS ES&T AirPub Date : 2025-02-11DOI: 10.1021/acsestair.4c0020010.1021/acsestair.4c00200
Xudong Zheng, Qinwen Tan, Jie Ren, Bin Luo, Danlin Song, Miao Feng, Hefan Liu, Yue Qin*, Yufang Hao, Liming Zeng, Xin Li, Sihua Lu, Huabin Dong and Shaodong Xie*,
{"title":"Daytime Ozone Production Determined by Ratios of Total Volatile Organic Compound Consumption to Nitrogen Oxide Concentrations","authors":"Xudong Zheng, Qinwen Tan, Jie Ren, Bin Luo, Danlin Song, Miao Feng, Hefan Liu, Yue Qin*, Yufang Hao, Liming Zeng, Xin Li, Sihua Lu, Huabin Dong and Shaodong Xie*, ","doi":"10.1021/acsestair.4c0020010.1021/acsestair.4c00200","DOIUrl":"https://doi.org/10.1021/acsestair.4c00200https://doi.org/10.1021/acsestair.4c00200","url":null,"abstract":"<p >To reduce the uncertainty in analyzing ozone (O<sub>3</sub>) sensitivities based on observed concentrations of volatile organic compounds (VOCs) and nitrogen dioxide, this study proposed the application of consumed VOC concentrations to establish their nonlinear relationship in the actual atmosphere. These parameters were calculated based on the reaction rates and online observations of VOCs, nitrogen dioxide, and O<sub>3</sub> concentrations at Deyang, Chengdu, and Meishan in the Chengdu Plain, China, during summer 2019. The nighttime isoprene consumption was maximum at 2.03 ppbv at Meishan. The daytime acetaldehyde consumption was a maximum at 2.68 ppbv at Deyang, possibly due to its higher primary emissions and secondary production and its consumption by both OH radicals and photolysis. When the ratios of the total consumed VOC concentrations to the observed or initial NO<sub><i>x</i></sub> (NO<sub><i>x</i></sub> = NO + NO<sub>2</sub>) concentrations were 3.51 ppbv ppbv<sup>–1</sup> or 2.22 ppbv ppbv<sup>–1</sup>, daytime O<sub>3</sub> variations reached a maximum of 8.45 ppbv or 7.52 ppbv, respectively. The ratios delineated the VOC-sensitive and NO<sub><i>x</i></sub>-sensitive areas. Over 98% of hourly data were in VOC-sensitive areas at both Chengdu and Meishan, respectively, while over 14% of hourly data belonged to NO<sub><i>x</i></sub>-sensitive areas at Deyang. This provided a more accurate method for assessing real-time O<sub>3</sub> sensitivity and thus implementing dynamic hierarchical control strategies.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"331–342 331–342"},"PeriodicalIF":0.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143608883","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}
ACS ES&T AirPub Date : 2025-01-31DOI: 10.1021/acsestair.4c0026210.1021/acsestair.4c00262
Yunjiang Zhang*, Jie Fang, Qingxiao Meng, Xinlei Ge, Hasna Chebaicheb, Olivier Favez and Jean-Eudes Petit*,
{"title":"An Ensemble Machine Learning Approach for Predicting Sources of Organic Aerosols Measured by Aerosol Mass Spectrometry","authors":"Yunjiang Zhang*, Jie Fang, Qingxiao Meng, Xinlei Ge, Hasna Chebaicheb, Olivier Favez and Jean-Eudes Petit*, ","doi":"10.1021/acsestair.4c0026210.1021/acsestair.4c00262","DOIUrl":"https://doi.org/10.1021/acsestair.4c00262https://doi.org/10.1021/acsestair.4c00262","url":null,"abstract":"<p >Long-term source apportionment of atmospheric organic aerosols (OA) is essential for supporting air pollution management strategies. While aerosol mass spectrometry (AMS) combined with traditional source apportionment tools can accurately identify various OA sources, they face efficiency challenges when processing large volumes of long-term data. This study proposes an ensemble machine learning approach to efficiently apportion OA sources from long-term AMS measurements. Using six-year observation of a simplified version of AMS (i.e., ACSM) in the Paris region along with OA factor data derived from positive matrix factorization analysis, we developed an ensemble machine learning source apportionment model. Compared to individual machine learning algorithms, the ensemble model substantially reduced the root-mean-square error (RMSE) and increased the correlation coefficient in predicting OA sources by approximately 30% and 5%, respectively. Sensitivity analysis with five years of baseline data revealed that model performance relatively stabilizes when the training data exceeds two years, with RMSE values for primary and secondary OA factors at 0.31–0.45 μg/m<sup>3</sup> and 0.69–0.84 μg/m<sup>3</sup>, respectively. This ensemble model not only enhances the efficiency of long-term OA source apportionment but also holds potential for near-real-time online applications.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"2 3","pages":"378–385 378–385"},"PeriodicalIF":0.0,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143609019","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}