ACS Environmental Au最新文献

{"title":"Hands are frequently contaminated with fecal bacteria and enteric pathogens globally: A systematic review and meta-analysis","authors":"M. Cantrell, É. Sylvestre, R. Scheidegger, L. Curchod, D. Gute, J. Griffiths, Timothy Ryan Julian, A. Pickering","doi":"10.1101/2022.07.11.22277510","DOIUrl":"https://doi.org/10.1101/2022.07.11.22277510","url":null,"abstract":"Enteric pathogen infections are a leading cause of morbidity and mortality globally, with the highest disease burden in low-income countries. Hands act as intermediaries in enteric pathogen transmission, transferring enteric pathogens between people and the environment through contact with food, water, and soil. In this study, we conducted a systematic review of prevalence and concentrations of fecal indicator microorganisms (i.e., E. coli, fecal coliform) and enteric pathogens on hands. We identified eighty studies, reporting 31,305 observations of hand contamination of people in community or household settings. The studies investigated 45 unique microorganisms, of which the most commonly reported indicators were E. coli and fecal coliforms. Hand contamination with 14 unique enteric pathogens was reported, with adenovirus and rotavirus as the most frequent. Mean E. coli prevalence on hands was 40% [95% CI 18%-62%] and mean fecal coliform prevalence was 42% [95% CI 16%-69%]. Hands were more likely to be contaminated with E. coli in low/lower-middle-income countries (prevalence: 49% [25% - 72%]) than in upper-middle/high-income countries (6% [1% - 12%]). In low/lower-middle income countries, E. coli prevalence was higher in urban compared to rural settings (52% mean prevalence in urban versus 33% in rural), although substantial heterogeneity between studies limited confidence in this finding. The review also highlighted the importance of standardizing hand sampling methods, as hand rinsing was associated with greater fecal contamination compared to other sampling methods.","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46736916","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":"Elucidating the Role of O2 Uncoupling in the Oxidative Biodegradation of Organic Contaminants by Rieske Non-heme Iron Dioxygenases","authors":"Charlotte E. Bopp,&nbsp;Nora M. Bernet,&nbsp;Hans-Peter E. Kohler and Thomas B. Hofstetter*,&nbsp;","doi":"10.1021/acsenvironau.2c00023","DOIUrl":"https://doi.org/10.1021/acsenvironau.2c00023","url":null,"abstract":"<p >Oxygenations of aromatic soil and water contaminants with molecular O₂ catalyzed by Rieske dioxygenases are frequent initial steps of biodegradation in natural and engineered environments. Many of these non-heme ferrous iron enzymes are known to be involved in contaminant metabolism, but the understanding of enzyme–substrate interactions that lead to successful biodegradation is still elusive. Here, we studied the mechanisms of O₂ activation and substrate hydroxylation of two nitroarene dioxygenases to evaluate enzyme- and substrate-specific factors that determine the efficiency of oxygenated product formation. Experiments in enzyme assays of 2-nitrotoluene dioxygenase (2NTDO) and nitrobenzene dioxygenase (NBDO) with methyl-, fluoro-, chloro-, and hydroxy-substituted nitroaromatic substrates reveal that typically 20–100% of the enzyme’s activity involves unproductive paths of O₂ activation with generation of reactive oxygen species through so-called O₂ uncoupling. The ¹⁸O and ¹³C kinetic isotope effects of O₂ activation and nitroaromatic substrate hydroxylation, respectively, suggest that O₂ uncoupling occurs after generation of Fe^III-(hydro)peroxo species in the catalytic cycle. While 2NTDO hydroxylates <i>ortho</i>-substituted nitroaromatic substrates more efficiently, NBDO favors <i>meta</i>-substituted, presumably due to distinct active site residues of the two enzymes. Our data implies, however, that the O₂ uncoupling and hydroxylation activity cannot be assessed from simple structure–reactivity relationships. By quantifying O₂ uncoupling by Rieske dioxygenases, our work provides a mechanistic link between contaminant biodegradation, the generation of reactive oxygen species, and possible adaptation strategies of microorganisms to the exposure of new contaminants.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsenvironau.2c00023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72199465","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":"Impacts of TROPOMI-Derived NOX Emissions on NO2 and O3 Simulations in the NCP during COVID-19","authors":"Yizhi Zhu,&nbsp;Cheng Liu*,&nbsp;Qihou Hu*,&nbsp;Jiahua Teng,&nbsp;Daian You,&nbsp;Chengxin Zhang,&nbsp;Jinping Ou,&nbsp;Ting Liu,&nbsp;Jinan Lin,&nbsp;Tianyi Xu and Xinhua Hong,&nbsp;","doi":"10.1021/acsenvironau.2c00013","DOIUrl":"https://doi.org/10.1021/acsenvironau.2c00013","url":null,"abstract":"<p >NO₂ and O₃ simulations have great uncertainties during the COVID-19 epidemic, but their biases and spatial distributions can be improved with NO₂ assimilations. This study adopted two top-down NO_<i>X</i> inversions and estimated their impacts on NO₂ and O₃ simulation for three periods: the normal operation period (P1), the epidemic lockdown period following the Spring Festival (P2), and back to work period (P3) in the North China Plain (NCP). Two TROPOspheric Monitoring Instrument (TROPOMI) NO₂ retrievals came from the Royal Netherlands Meteorological Institute (KNMI) and the University of Science and Technology of China (USTC), respectively. Compared to the prior NO_<i>X</i> emissions, the two TROPOMI posteriors greatly reduced the biases between simulations with in situ measurements (NO₂ MREs: prior 85%, KNMI −27%, USTC −15%; O₃ MREs: Prior −39%, KNMI 18%, USTC 11%). The NO_<i>X</i> budgets from the USTC posterior were 17–31% higher than those from the KNMI one. Consequently, surface NO₂ levels constrained by USTC-TROPOMI were 9–20% higher than those by the KNMI one, and O₃ is 6–12% lower. Moreover, USTC posterior simulations showed more significant changes in adjacent periods (surface NO₂: P2 vs P1, −46%, P3 vs P2, +25%; surface O₃: P2 vs P1, +75%, P3 vs P2, +18%) than the KNMI one. For the transport flux in Beijing (BJ), the O₃ flux differed by 5–6% between the two posteriori simulations, but the difference of NO₂ flux between P2 and P3 was significant, where the USTC posterior NO₂ flux was 1.5–2 times higher than the KNMI one. Overall, our results highlight the discrepancies in NO₂ and O₃ simulations constrained by two TROPOMI products and demonstrate that the USTC posterior has lower bias in the NCP during COVD-19.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsenvironau.2c00013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72198801","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":"Primary Succession Changes the Composition and Functioning of the Protist Community on Mine Tailings, Especially Phototrophic Protists","authors":"Yongbin Li,&nbsp;Pin Gao,&nbsp;Xiaoxu Sun,&nbsp;Baoqin Li,&nbsp;Lifang Guo,&nbsp;Rui Yang,&nbsp;Xianfa Su,&nbsp;Wenlong Gao,&nbsp;Zhimin Xu,&nbsp;Geng Yan,&nbsp;Qi Wang and Weimin Sun*,&nbsp;","doi":"10.1021/acsenvironau.1c00066","DOIUrl":"10.1021/acsenvironau.1c00066","url":null,"abstract":"<p >Primary succession in mine tailings is a prerequisite for tailing vegetation. Microorganisms, including bacteria, fungi, and protists, play an important role in this process in the driving force for improving the nutritional status. Compared to bacteria and fungi, protist populations have rarely been investigated regarding their role in mine tailings, especially for those inhabiting tailings associated with primary succession. Protists are the primary consumers of fungi and bacteria, and their predatory actions promote the release of nutrients immobilized in the microbial biomass, as well as the uptake and turnover of nutrients, affecting the functions of the wider ecosystems. In this study, three different types of mine tailings associated with three successional stages (original tailings, biological crusts, and <i>Miscanthus sinensis</i> grasslands) were selected to characterize the protistan community diversity, structure, and function during primary succession. Some members classified as consumers dominated the network of microbial communities in the tailings, especially in the original bare land tailings. The keystone phototrophs of Chlorophyceae and Trebouxiophyceae showed the highest relative abundance in the biological crusts and grassland rhizosphere, respectively. In addition, the co-occurrences between protist and bacterial taxa demonstrated that the proportion of protistan phototrophs gradually increased during primary succession. Further, the metagenomic analysis of protistan metabolic potential showed that abundances of many functional genes associated with photosynthesis increased during the primary succession of tailings. Overall, these results suggest that the primary succession of mine tailings drives the changes observed in the protistan community, and in turn, the protistan phototrophs facilitate the primary succession of tailings. This research offers an initial insight into the changes in biodiversity, structure, and function of the protistan community during ecological succession on tailings.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/2b/0f/vg1c00066.PMC10125303.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9356804","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":"Plastic Burning Impacts on Atmospheric Fine Particulate Matter at Urban and Rural Sites in the USA and Bangladesh","authors":"Md. Robiul Islam,&nbsp;Josie Welker,&nbsp;Abdus Salam and Elizabeth A. Stone*,&nbsp;","doi":"10.1021/acsenvironau.1c00054","DOIUrl":"10.1021/acsenvironau.1c00054","url":null,"abstract":"<p >To better understand the impact of plastic burning on atmospheric fine particulate matter (PM_2.5), we evaluated two methods for the quantification of 1,3,5-triphenylbenzene (TPB), a molecular tracer of plastic burning. Compared to traditional solvent-extraction gas chromatography mass spectrometry (GCMS) techniques, thermal-desorption (TD) GCMS provided higher throughput, lower limits of detection, more precise spike recoveries, a wider linear quantification range, and reduced solvent use. This method enabled quantification of TPB in fine particulate matter (PM_2.5) samples collected at rural and urban sites in the USA and Bangladesh. These analyses demonstrated a measurable impact of plastic burning at 5 of the 6 study locations, with the largest absolute and relative TPB concentrations occurring in Dhaka, Bangladesh, where plastic burning is expected to be a significant source of PM_2.5. Background-level contributions of plastic burning in the USA were estimated to be 0.004–0.03 μg m^–3 of PM_2.5 mass. Across the four sites in the USA, the lower estimate of plastic burning contributions to PM_2.5 ranged 0.04–0.8%, while the median estimate ranged 0.3–3% (save for Atlanta, Georgia, in the wintertime at 2–7%). The results demonstrate a consistent presence of plastic burning emissions in ambient PM_2.5 across urban and rural sites in the USA, with a relatively small impact in comparison to other anthropogenic combustion sources in most cases. Much higher TPB concentrations were observed in Dhaka, with estimated plastic burning impacts on PM_2.5 ranging from a lower estimate of 0.3–1.8 μg m^–3 (0.6–2% of PM_2.5) and the median estimate ranging 2–35 μg m^–3 (5–15% of PM_2.5). The methodological advances and new measurements presented herein help to assess the air quality impacts of burning plastic more broadly.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9502013/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10621177","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":"Exceptional Mineral Scaling Resistance from the Surface Gas Layer: Impacts of Surface Wetting Properties and the Gas Layer Charging Mechanism","authors":"Thomas Horseman,&nbsp; and ,&nbsp;Shihong Lin*,&nbsp;","doi":"10.1021/acsenvironau.2c00011","DOIUrl":"10.1021/acsenvironau.2c00011","url":null,"abstract":"<p >Mineral scaling is a phenomenon that occurs on submerged surfaces in contact with saline solutions. In membrane desalination, heat exchangers, and marine structures, mineral scaling reduces process efficiency and eventually leads to process failure. Therefore, achieving long-term scaling resistance is beneficial to enhancing process performance and reducing operating and maintenance costs. While evidence shows that superhydrophobic surfaces may reduce mineral scaling kinetics, prolonged scaling resistance is limited due to the finite stability of the entrained gas layer present in a Cassie–Baxter wetting state. Additionally, superhydrophobic surfaces are not always feasible for all applications, but strategies for long-term scaling resistance with smooth or even hydrophilic surfaces are often overlooked. In this study, we elucidate the role of interfacial nanobubbles on the scaling kinetics of submerged surfaces of varied wetting properties, including those that do not entrain a gas layer. We show that both solution conditions and surface wetting properties that promote interfacial bubble formation enhances scaling resistance. In the absence of interfacial bubbles, scaling kinetics decrease as surface energy decreases, while the presence of bulk nanobubbles enhances the scaling resistance of the surface with any wetting property. The findings in this study allude to scaling mitigation strategies that are enabled by solution and surface properties that promote the formation and stability of interfacial gas layers and provide insights to surface and process design for greater scaling resistance.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/0e/6d/vg2c00011.PMC10125293.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9356805","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":"Environmental Engineers Addressing the Grand Challenges of the 21st Century","authors":"Fangqiong Ling*,&nbsp; and ,&nbsp;Keri C. Hornbuckle*,&nbsp;","doi":"10.1021/acsenvironau.2c00025","DOIUrl":"10.1021/acsenvironau.2c00025","url":null,"abstract":"W are happy to introduce our third issue of ACS Environmental Au in 2022. With this collection of eight research articles and critical reviews, we are proud to highlight the work of environmental engineers and scientists across the globe, addressing some of the most pressing challenges facing society. “The discipline of environmental engineering has no single, widely agreed-upon definition”here we quote the 2019 report from an ad hoc committee of the Water Science and Technology Board of the National Academies of Sciences, Engineering, and Medicine. In that inspiring report, in lieu of defining “environmental engineering” or identifying specific environmental challenges, the committee chose to identify “the most pressing challenges of the 21st century for which the expertise of environmental engineering will be needed to help resolve or manage’’. These grand challenges include (a) providing a sustainable supply of food, water and energy, (b) reducing climate change and adapting to its impacts, (c) designing a future without pollution and waste, (d) creating efficient, healthy, resilient cities, and (e) fostering informed decisions and actions. The COVID-19 pandemic has provided an additional challenge, and environmental engineers have stepped up to provide new technologies to help curb the pandemic. The contributions in this issue address many of these grand challenges of the 21 century. Below you will find a synopsis of the articles and review in this issue, grouped by the above-mentioned challenges that they are helping address.","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/b7/f8/vg2c00025.PMC10114622.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9352482","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":"Daily Emission Patterns of Coal-Fired Power Plants in China Based on Multisource Data Fusion","authors":"Nana Wu,&nbsp;Guannan Geng,&nbsp;Xinying Qin,&nbsp;Dan Tong,&nbsp;Yixuan Zheng,&nbsp;Yu Lei and Qiang Zhang*,&nbsp;","doi":"10.1021/acsenvironau.2c00014","DOIUrl":"10.1021/acsenvironau.2c00014","url":null,"abstract":"<p >Daily emission estimates are essential for tracking the dynamic changes in emission sources. In this work, we estimate daily emissions of coal-fired power plants in China during 2017–2020 by combining information from the unit-based China coal-fired Power plant Emissions Database (CPED) and real-time measurements from continuous emission monitoring systems (CEMS). We develop a step-by-step method to screen outliers and impute missing values for data from CEMS. Then, plant-level daily profiles of flue gas volume and emissions obtained from CEMS are coupled with annual emissions from CPED to derive daily emissions. Reasonable agreement is found between emission variations and available statistics (i.e., monthly power generation and daily coal consumption). Daily power emissions are in the range of 6267–12,994, 0.4–1.3, 6.5–12.0, and 2.5–6.8 Gg for CO₂, PM_2.5, NO<i>_x</i>, and SO₂, respectively, with high emissions in winter and summer caused by heating and cooling demand. Our estimates can capture sudden decreases (e.g., those associated with COVID-19 lockdowns and short-term emission controls) or increases (e.g., those related to a drought) in daily power emissions during typical socioeconomic events. We also find that weekly patterns from CEMS exhibit no obvious weekend effect compared to those in previous studies. The daily power emissions will help to improve chemical transport modeling and facilitate policy formulation.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/9a/a5/vg2c00014.PMC10125283.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9414242","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":"Direct Air Capture of CO2 Using a Liquid Amine–Solid Carbamic Acid Phase-Separation System Using Diamines Bearing an Aminocyclohexyl Group","authors":"Soichi Kikkawa,&nbsp;Kazushi Amamoto,&nbsp;Yu Fujiki,&nbsp;Jun Hirayama,&nbsp;Gen Kato,&nbsp;Hiroki Miura,&nbsp;Tetsuya Shishido and Seiji Yamazoe*,&nbsp;","doi":"10.1021/acsenvironau.1c00065","DOIUrl":"https://doi.org/10.1021/acsenvironau.1c00065","url":null,"abstract":"<p >The phase separation between a liquid amine and the solid carbamic acid exhibited &gt;99% CO₂ removal efficiency under a 400 ppm CO₂ flow system using diamines bearing an aminocyclohexyl group. Among them, isophorone diamine [IPDA; 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine] exhibited the highest CO₂ removal efficiency. IPDA reacted with CO₂ in a CO₂/IPDA molar ratio of ≥1 even in H₂O as a solvent. The captured CO₂ was completely desorbed at 333 K because the dissolved carbamate ion releases CO₂ at low temperatures. The reusability of IPDA under CO₂ adsorption-and-desorption cycles without degradation, the &gt;99% efficiency kept for 100 h under direct air capture conditions, and the high CO₂ capture rate (201 mmol/h for 1 mol of amine) suggest that the phase separation system using IPDA is robust and durable for practical use.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsenvironau.1c00065","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72199554","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":"Revisiting the Key Driving Processes of the Decadal Trend of Aerosol Acidity in the U.S","authors":"Guangjie Zheng,&nbsp;Hang Su and Yafang Cheng*,&nbsp;","doi":"10.1021/acsenvironau.1c00055","DOIUrl":"10.1021/acsenvironau.1c00055","url":null,"abstract":"Acidity is one essential parameter in determining the aqueous phase physical and chemical processes in the atmosphere and strongly influences the climate, ecological, and health effects of aerosols. Traditionally, aerosol acidity is thought to increase with emissions of atmospheric acidic substances (SO2, NOx, etc.) and decrease with that of alkaline ones (NH3, dust, etc.). However, decade-long observations in southeastern U.S. seem to disagree with this hypothesis: while the emissions of NH3 versus SO2 enhanced by over three times, the predicted aerosol acidity is stable, and the observed particle-phase ammonium-to-sulfate ratio is even decreasing. Here, we investigated into this issue with the recently proposed multiphase buffer theory. We show that historically, there is a transition in the dominant drivers of aerosol acidity in this region. Under the ammonia-poor conditions before ∼2008, the acidity is governed by HSO4–/SO42– buffering and the water self-buffering effect. Under the ammonia-rich conditions after ∼2008, aerosol acidity is mainly buffered by NH4+/NH3. Buffering from the organic acids is negligible in the investigated period. In addition, the observed decrease in ammonium-to-sulfate ratio is due to the increased importance of non-volatile cations, especially after ∼2014. We predict that until ∼2050, the aerosols will remain in the ammonia-buffered regime, and the nitrate will remain largely (>98%) in the gas phase in southeastern U.S.","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10125332/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9726286","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}