ACS ES&T Air最新文献

{"title":"North American Fine Particulate Matter Chemical Composition for 2000-2022 from Satellites, Models, and Monitors: The Changing Contribution of Wildfires.","authors":"Aaron van Donkelaar, Randall V Martin, Bonne Ford, Chi Li, Amanda J Pappin, Siyuan Shen, Dandan Zhang","doi":"10.1021/acsestair.4c00151","DOIUrl":"10.1021/acsestair.4c00151","url":null,"abstract":"<p><p>Air quality management benefits from an in-depth understanding of the emissions associated with, and composition of, local PM_2.5 concentrations. Here, we investigate the changing role of biomass burning emissions to North American PM_2.5 exposure by combining multiple satellite-, ground-, and simulation-based data sets biweekly at a 0.01° × 0.01° resolution from 2000 to 2022. We also developed a Buffered Leave Cluster Out (BLeCO) method to address autocorrelation and computational cost in cross-validation. Biomass burning emissions contribute an increasingly large fraction to PM_2.5 exposure in the United States and Canada, with national annual population-weighted mean contributions increasing from 0.4 μg/m³ (3-5%) in 2000-2004 to 0.8-0.9 μg/m³ (9-14%) by 2019-2022, led by western North American 2019-2022 annual contributions of 1.4-1.9 μg/m³ (15-27%) and maximum seasonal contributions of 3.3-5.5 μg/m³ (29-49%). Other components such as nonbiomass burning Organic Matter (OM) and nitrate can be regionally as (or more) important, albeit with distinct seasonal variability. The contribution of total OM to PM_2.5 exposure in the United States in 2016-2022 is 42.2%, comparable to all other anthropogenically sourced components combined. Comparison of BLeCO and random 10-fold cross-validation suggests that random 10-fold cross-validation may significantly underrepresent true uncertainty for total PM_2.5 concentrations due to the clustered nature of PM_2.5 ground-based monitoring.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1589-1600"},"PeriodicalIF":0.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11651298/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857504","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":"North American Fine Particulate Matter Chemical Composition for 2000–2022 from Satellites, Models, and Monitors: The Changing Contribution of Wildfires","authors":"Aaron van Donkelaar*,&nbsp;Randall V. Martin,&nbsp;Bonne Ford,&nbsp;Chi Li,&nbsp;Amanda J. Pappin,&nbsp;Siyuan Shen and Dandan Zhang,&nbsp;","doi":"10.1021/acsestair.4c0015110.1021/acsestair.4c00151","DOIUrl":"https://doi.org/10.1021/acsestair.4c00151https://doi.org/10.1021/acsestair.4c00151","url":null,"abstract":"<p >Air quality management benefits from an in-depth understanding of the emissions associated with, and composition of, local PM_2.5 concentrations. Here, we investigate the changing role of biomass burning emissions to North American PM_2.5 exposure by combining multiple satellite-, ground-, and simulation-based data sets biweekly at a 0.01° × 0.01° resolution from 2000 to 2022. We also developed a Buffered Leave Cluster Out (BLeCO) method to address autocorrelation and computational cost in cross-validation. Biomass burning emissions contribute an increasingly large fraction to PM_2.5 exposure in the United States and Canada, with national annual population-weighted mean contributions increasing from 0.4 μg/m³ (3–5%) in 2000–2004 to 0.8–0.9 μg/m³ (9–14%) by 2019–2022, led by western North American 2019–2022 annual contributions of 1.4–1.9 μg/m³ (15–27%) and maximum seasonal contributions of 3.3–5.5 μg/m³ (29–49%). Other components such as nonbiomass burning Organic Matter (OM) and nitrate can be regionally as (or more) important, albeit with distinct seasonal variability. The contribution of total OM to PM_2.5 exposure in the United States in 2016–2022 is 42.2%, comparable to all other anthropogenically sourced components combined. Comparison of BLeCO and random 10-fold cross-validation suggests that random 10-fold cross-validation may significantly underrepresent true uncertainty for total PM_2.5 concentrations due to the clustered nature of PM_2.5 ground-based monitoring.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1589–1600 1589–1600"},"PeriodicalIF":0.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142843086","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":"Pristine and Aged Microplastics Can Nucleate Ice through Immersion Freezing","authors":"Heidi L. Busse,&nbsp;Devaka Dharmapriya Ariyasena,&nbsp;Jessica Orris and Miriam Arak Freedman*,&nbsp;","doi":"10.1021/acsestair.4c0014610.1021/acsestair.4c00146","DOIUrl":"https://doi.org/10.1021/acsestair.4c00146https://doi.org/10.1021/acsestair.4c00146","url":null,"abstract":"<p >Microplastics (MP) are ubiquitous in the environment; their atmospheric relevance is being increasingly recognized. Because of their atmospheric concentrations, there is the question of whether MP can act as ice nucleating particles in the atmosphere. This study investigates the immersion freezing activity of lab-prepared MP of four different compositions─low density polyethylene (LDPE), polypropylene (PP), poly(vinyl chloride) (PVC), and poly(ethylene terephthalate) (PET)─using droplet freezing assays. The MP are also exposed to ultraviolet light, ozone, sulfuric acid, and ammonium sulfate to mimic environmental aging of the plastics to elucidate the role that these processes play in the ice nucleating activity of MP. Results show that all studied MP act as immersion nuclei, and aging processes can modify this ice nucleating activity, leading, primarily, to decreases in ice nucleating activity for LDPE, PP, and PET. The ice nucleating activity of PVC generally increased following aging, which we attribute to a cleaning of chemical defects present on the surface of the stock material. Chemical changes were monitored with infrared spectroscopy (ATR-FTIR), and the growth of a peak at 1650–1800 cm^–1 was associated with a decrease in ice nucleating activity while loss of an existing peak in that region was associated with an increase in ice nucleating activity. The studied MP have ice nucleating activities sufficient to be a non-negligible source of ice nucleating particles in the atmosphere if present in sufficiently high concentrations.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1579–1588 1579–1588"},"PeriodicalIF":0.0,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142851235","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":"Findings from Biomass Burning Field Campaigns Set Directions for Future Research on Atmospheric Impacts","authors":"Kelley C. Barsanti*,&nbsp;Steven S. Brown*,&nbsp;Emily V. Fischer,&nbsp;Johannes W. Kaiser,&nbsp;Chelsea E. Stockwell,&nbsp;Chelsea Thompson,&nbsp;Carsten Warneke and Robert J. Yokelson*,&nbsp;","doi":"10.1021/acsestair.4c0027610.1021/acsestair.4c00276","DOIUrl":"https://doi.org/10.1021/acsestair.4c00276https://doi.org/10.1021/acsestair.4c00276","url":null,"abstract":"","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1507–1510 1507–1510"},"PeriodicalIF":0.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844163","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":"Low Methane Emissions from the Natural Gas Distribution System Indicated by Mobile Measurements in a Chinese Megacity Hangzhou","authors":"Shuang Zhao,&nbsp;Yuzhong Zhang*,&nbsp;Ruosi Liang,&nbsp;Wei Chen,&nbsp;Xinchun Xie,&nbsp;Rui Wang,&nbsp;Zheng Xia,&nbsp;Jiandong Shen,&nbsp;Yilong Wang and Huilin Chen,&nbsp;","doi":"10.1021/acsestair.4c0006810.1021/acsestair.4c00068","DOIUrl":"https://doi.org/10.1021/acsestair.4c00068https://doi.org/10.1021/acsestair.4c00068","url":null,"abstract":"<p >The consumption of natural gas (NG) in China has quadrupled over the past decade. However, there is an absence of measurement-based assessment of methane emissions from NG consumption, including those from the urban distribution network. Here, we conducted a mobile survey with concurrent measurements of ambient methane concentrations, carbon dioxide concentrations, and ¹³CH₄ isotopic signatures in the center and suburban areas of Hangzhou, a megacity in East China, from November 2021 to June 2022. We detected 176 leak indications in the 1408 km road covered with 32% attributed to NG leaks based on the source isotopic signature and the methane-to-carbon dioxide ratio derived from the Keeling plot and measured concentrations. We quantified the flux using Weller’s empirical equation, which yielded an emission factor of 115 L·d^–1·km^–1 in Hangzhou. The value ranges from 16 to 314 L·d^–1·km^–1 by accounting for various uncertainty sources. This emission factor falls on the lower end compared to previous studies conducted in North American and European cities. Our findings confirm the effectiveness of mobile surveys in detecting methane emission sources in urban China.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1511–1518 1511–1518"},"PeriodicalIF":0.0,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844024","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":"Campus–Community Partnership to Characterize Air Pollution in a Neighborhood Impacted by Major Transportation Infrastructure","authors":"Emily Farrar,&nbsp;Natalie Kobayaa,&nbsp;Weaam Jaafar,&nbsp;Sara Torbatian,&nbsp;Shayamila Mahagammulla Gamage,&nbsp;Jeff Brook,&nbsp;Arthur Chan,&nbsp;Greg Evans,&nbsp;Cheol-Heon Jeong,&nbsp;Jeffrey Siegel,&nbsp;Junshi Xu and Marianne Hatzopoulou*,&nbsp;","doi":"10.1021/acsestair.4c0015510.1021/acsestair.4c00155","DOIUrl":"https://doi.org/10.1021/acsestair.4c00155https://doi.org/10.1021/acsestair.4c00155","url":null,"abstract":"<p >This study investigates air quality in a Toronto community located between an airport and an expressway. A community science approach was adopted for data collection and interpretation, and a partnership was formed between a local neighborhood association, university researchers, the municipal government, and the local airport authority. Community scientists placed low-cost sensors on outdoor balconies and inside homes for 28 weeks between 2020 and 2022, measuring particle number (PN) concentrations of particulate matter (PM) with diameters between 0.5 and 2.5 μm. Indoors, the PN concentrations increased during cooking and other activities. During periods with minimal indoor activities, indoor levels closely followed the outdoor signal. Median indoor/outdoor (IO) ratios varied between 0.4 and 0.87 across sampling months. Median outdoor PN concentrations varied from 1 to 4 #/cm³ and were influenced by local and regional sources. Outdoor PN concentrations were significantly correlated to PM_2.5 and nitrogen dioxide at a downtown reference station; the latter suggests that traffic emissions from the nearby expressway contribute to PN concentrations in the neighborhood. An analysis of outdoor ultrafine particle (UFP) data collected at a single location suggests that the airport is a source of UFP in the neighborhood. Community engagement was enabled through involvement in study design, execution, and knowledge mobilization.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1601–1616 1601–1616"},"PeriodicalIF":0.0,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142850348","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":"Characterization of Oxidative Potential and Ecotoxicity of the Organic Fraction of Particulate Matter in a Coastal City in China: Implications for Human Respiratory Health","authors":"Ke Chen,&nbsp;Jingsha Xu,&nbsp;Dongsheng Ji,&nbsp;Lei Tong,&nbsp;Tianfeng He,&nbsp;Tong Chen,&nbsp;Hang Xiao and Jun He*,&nbsp;","doi":"10.1021/acsestair.4c0017710.1021/acsestair.4c00177","DOIUrl":"https://doi.org/10.1021/acsestair.4c00177https://doi.org/10.1021/acsestair.4c00177","url":null,"abstract":"<p >This study investigated the size distributions, oxidative potential (OP_v), and acute ecotoxicity index (TI) of atmospheric organic aerosols during haze and nonhaze periods in a coastal city in China. Results indicated higher OP_v and TI levels during haze periods, with trimodal variations: the highest OP_v peak in the 7.2–10 μm and the highest TI peak in the 0–0.49 μm. For the first time, multilayer perception analysis was applied to predict both OP_v and ecotoxicity, offering enhanced accuracy by capturing synergistic and antagonistic interactions among various chemical components. Lung deposition doses of size-resolved PM inducing OP_v and TI within the human respiratory system were estimated. Findings revealed that the largest particles (7.2–10 μm) predominantly affected the head airways, whereas particles in the 1.5–3.0 μm significantly impacted the pulmonary region. This behavior is attributed to quinones and high-molecular-weight polycyclic aromatic hydrocarbons (HMW-PAHs), which have higher deposition efficiency in the head airways and elevated concentrations in the pulmonary region, respectively. To mitigate health risks associated with these toxicants, efforts should target their size-dependent properties and lung deposition efficiency, considering various health end points. This study underscores the need for size-specific mitigation strategies to effectively address the differential impacts of PM on respiratory health.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1650–1661 1650–1661"},"PeriodicalIF":0.0,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844178","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":"The Impact of Decarbonization on Particulate Soiling of Solar Panels","authors":"Drew Shindell*,&nbsp;Ivan Petropoulos,&nbsp;Greg Faluvegi,&nbsp;Luke Parsons and Michael Bergin,&nbsp;","doi":"10.1021/acsestair.4c0010510.1021/acsestair.4c00105","DOIUrl":"https://doi.org/10.1021/acsestair.4c00105https://doi.org/10.1021/acsestair.4c00105","url":null,"abstract":"<p >Climate researchers have examined many impacts of climate change on energy supply and demand under various scenarios. However, the effect of changing particulate deposition onto solar panel surfaces on solar power production efficiency (i.e., soiling) has not been studied. We therefore characterize probabilistic outcomes across multiple climate models and scenarios. We find large current regional losses (up to 40% without manual cleaning, up to 20% with monthly cleaning and rain removal) in generation that grow slightly under a high-emission scenario, largely due to regional increases in windblown dust. In contrast, under a low-emissions scenario, potential production increases significantly (2–8% interquartile range with only rain removal) due to reduced soiling, especially in regions of Asia and Africa where anthropogenic aerosols are major contributors to soiling. Projected changes vary widely across models in many dusty areas outside of the Sahara and Arabia. Differences can also be large in regions dominated by anthropogenic aerosols, such as Nigeria, eastern China, and northern India, where the full range across modeled potential power production changes extends from −1 to +11% for the end of the century (without manual cleaning), underscoring the need to consider multiple climate models. With large increases in projected solar power deployment, the relatively small potential production increases reported here could nevertheless represent a large dividend in additional energy production. Hence, reductions in air pollution attributable to decarbonization could provide positive feedback under which a greater deployment of solar power (or other renewables) increases the production of solar power, facilitating the transition to renewable energy.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1531–1540 1531–1540"},"PeriodicalIF":0.0,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844179","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":"Full-Volatility Reactive Organic Carbon Emissions from Volatile Chemical Products in Mainland China","authors":"Yangjun Wang,&nbsp;Jiayu Huang,&nbsp;Bin Zhao,&nbsp;Yufei Du,&nbsp;Ling Huang,&nbsp;Demian Lai,&nbsp;Qingfang Su,&nbsp;Kasemsan Manomaiphiboon and Li Li*,&nbsp;","doi":"10.1021/acsestair.4c0011610.1021/acsestair.4c00116","DOIUrl":"https://doi.org/10.1021/acsestair.4c00116https://doi.org/10.1021/acsestair.4c00116","url":null,"abstract":"<p >Volatile chemical products (VCPs), including personal care products, general cleaners, architectural coatings, pesticides, adhesives, and others, are becoming increasingly significant anthropogenic sources of reactive organic carbon (ROC) in China. These ROC serve as critical precursors to ozone (O₃) and secondary organic aerosols (SOAs). Therefore, it is essential to estimate ROC emissions from VCPs in China accurately. In this study, the VCPy framework developed by the U.S. EPA was used to simulate ROC evaporative emissions from VCPs in mainland China, and its emission inventory was established. The results indicate that in 2019, the total ROC emissions from VCP sources in mainland China amounted to 9.4 Tg (6.9 TgC) with a 95% confidence interval of 8.4–11.8 Tg (6.2–8.7 TgC). The category of paints and coatings emerged as the dominant contributor to ROC emissions, emitting 6.0 Tg (4.4 TgC), accounting for 63.7% of total ROC emissions, followed by the category of cleaning products at 11.2% and the category of adhesives at 10.1%. Among ROC emissions, volatile organic compounds (VOCs) accounted for the largest proportion, followed by intermediate-volatility organic compounds (IVOCs), accounting for 23.6%. Oxygenated organic compounds and aromatics were the dominant components emitted from VCPs, accounting for 48.0% and 31.0% of ROC emission mass, respectively. Moreover, the mass proportion of oxygenated organic compounds in IVOC emissions was 72.0%. However, oxygenated organic compounds and aromatics were still predominantly emitted in the form of VOCs. Additionally, the O₃ formation potential (OFP) and SOA formation potential (SOAFP) of the ROC emissions from VCPs were estimated at 32.0 and 0.5 Tg, respectively, suggesting the significant impact of ROC emissions on O₃ and SOA from VCP sources. Emissions of oxygenated organic compounds contributed significantly to OFP and SOAFP by 33.8% and 17.1%, respectively. By comparing with measurement data, the VCPy framework can reliably reproduce the emissions of key species from VCPs in mainland China. This study provides essential basic data for a more comprehensive assessment of the impact of VCP emissions on SOA and ozone in mainland China.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1541–1553 1541–1553"},"PeriodicalIF":0.0,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142851217","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":"Vertical Variations in Biogenic Organic Nitrates at Two Temperate Forest Sites","authors":"Dandan Wei,&nbsp;Dylan B. Millet,&nbsp;Paul B. Shepson and Allison L. Steiner*,&nbsp;","doi":"10.1021/acsestair.4c0012310.1021/acsestair.4c00123","DOIUrl":"https://doi.org/10.1021/acsestair.4c00123https://doi.org/10.1021/acsestair.4c00123","url":null,"abstract":"<p >Forest canopies emit biogenic volatile organic compounds (BVOC), which contribute to the formation of regional ozone and secondary organic aerosol (SOA) formation. In the presence of NO_<i>x</i>, atmospheric oxidation of BVOC can produce organic nitrates that are an important component of SOA and act as a reservoir for NO_<i>x</i>, regulating local and regional atmospheric chemistry. Prior field observations of organic nitrates have focused on the above-canopy observations, yet there is little understanding of the vertical profiles of SOA and organic nitrates relative to the forest canopy emission sources. Here we contrast organic nitrate formation at two mixed deciduous forested ecosystems (the University of Michigan Biological Station (UMBS) and the Southern Aerosol Oxidant Study (SOAS) site in Alabama) with distinct differences in BVOC and NO_<i>x</i> to understand the formation of organic nitrates in and above a forest canopy. Gas-phase BVOC and NO_<i>x</i> concentrations are higher at SOAS than at UMBS, but the isoprene/monoterpene ratio is similar. We use a one-dimensional canopy model (Forest Canopy-Atmosphere Transfer Model version 2.0) to investigate the vertical profiles of isoprene- and monoterpene-derived secondary organic aerosol formation (iSOA and MT-SOA, respectively), with a focus on the aerosol organic nitrate. Simulated total iSOA shows similar temporal patterns as above-canopy observations at both sites, with the dominant fraction (50–80%) formed by isoprene epoxydiol (IEPOX). Within the canopy, the organic nitrate component of iSOA (iNIT-SOA) remains relatively small (10–20%) with slightly higher concentrations simulated at SOAS. The simulated iSOA composition at the two sites is similar, with four carbon (C4) nitrates dominating in the canopy and tetrafunctional nitrates dominating in the boundary layer. MT-SOA has different diurnal cycles at the two sites and is about 2–4 times greater at SOAS than UMBS, although the model underpredicts the observed top-of-canopy MT-SOA at both sites. The simulated organic nitrate component of the total MT-SOA (mNIT-SOA) is about 40% of the MT-SOA at SOAS and 20% at UMBS. Sensitivity analyses suggest that iNIT-SOA is highly sensitive to NO levels, while mNIT-SOA is more sensitive to dry deposition of preexisting organic particles. Overall, the 1D modeling suggests that organic nitrate aerosols are greater in and above the canopy near BVOC sources with a decrease in fractional contribution to total biogenic SOA with height in the boundary layer. Finally, organic nitrate aerosol composition can vary between similar ecosystems depending on the regional speciated BVOC emissions.</p>","PeriodicalId":100014,"journal":{"name":"ACS ES&T Air","volume":"1 12","pages":"1554–1567 1554–1567"},"PeriodicalIF":0.0,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844208","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}