Pub Date : 2022-06-29DOI: 10.1021/acsenvironau.1c00066
Yongbin Li, Pin Gao, Xiaoxu Sun, Baoqin Li, Lifang Guo, Rui Yang, Xianfa Su, Wenlong Gao, Zhimin Xu, Geng Yan, Qi Wang and Weimin Sun*,
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 Miscanthus sinensis 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.
{"title":"Primary Succession Changes the Composition and Functioning of the Protist Community on Mine Tailings, Especially Phototrophic Protists","authors":"Yongbin Li, Pin Gao, Xiaoxu Sun, Baoqin Li, Lifang Guo, Rui Yang, Xianfa Su, Wenlong Gao, Zhimin Xu, Geng Yan, Qi Wang and Weimin Sun*, ","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":"2 5","pages":"396–408"},"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}
Pub Date : 2022-06-09DOI: 10.1021/acsenvironau.1c00054
Md. Robiul Islam, Josie Welker, Abdus Salam and Elizabeth A. Stone*,
To better understand the impact of plastic burning on atmospheric fine particulate matter (PM2.5), 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 (PM2.5) 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 PM2.5. Background-level contributions of plastic burning in the USA were estimated to be 0.004–0.03 μg m–3 of PM2.5 mass. Across the four sites in the USA, the lower estimate of plastic burning contributions to PM2.5 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 PM2.5 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 PM2.5 ranging from a lower estimate of 0.3–1.8 μg m–3 (0.6–2% of PM2.5) and the median estimate ranging 2–35 μg m–3 (5–15% of PM2.5). The methodological advances and new measurements presented herein help to assess the air quality impacts of burning plastic more broadly.
{"title":"Plastic Burning Impacts on Atmospheric Fine Particulate Matter at Urban and Rural Sites in the USA and Bangladesh","authors":"Md. Robiul Islam, Josie Welker, Abdus Salam and Elizabeth A. Stone*, ","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<sub>2.5</sub>), 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<sub>2.5</sub>) 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<sub>2.5</sub>. Background-level contributions of plastic burning in the USA were estimated to be 0.004–0.03 μg m<sup>–3</sup> of PM<sub>2.5</sub> mass. Across the four sites in the USA, the lower estimate of plastic burning contributions to PM<sub>2.5</sub> 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<sub>2.5</sub> 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<sub>2.5</sub> ranging from a lower estimate of 0.3–1.8 μg m<sup>–3</sup> (0.6–2% of PM<sub>2.5</sub>) and the median estimate ranging 2–35 μg m<sup>–3</sup> (5–15% of PM<sub>2.5</sub>). 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":"2 5","pages":"409–417"},"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}
Pub Date : 2022-05-31DOI: 10.1021/acsenvironau.2c00011
Thomas Horseman, and , Shihong Lin*,
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.
{"title":"Exceptional Mineral Scaling Resistance from the Surface Gas Layer: Impacts of Surface Wetting Properties and the Gas Layer Charging Mechanism","authors":"Thomas Horseman, and , Shihong Lin*, ","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":"2 5","pages":"418–427"},"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}
Pub Date : 2022-05-18DOI: 10.1021/acsenvironau.2c00025
Fangqiong Ling*, and , Keri C. Hornbuckle*,
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.
{"title":"Environmental Engineers Addressing the Grand Challenges of the 21st Century","authors":"Fangqiong Ling*, and , Keri C. Hornbuckle*, ","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":"2 3","pages":"176–177"},"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}
Pub Date : 2022-05-17DOI: 10.1021/acsenvironau.2c00014
Nana Wu, Guannan Geng, Xinying Qin, Dan Tong, Yixuan Zheng, Yu Lei and Qiang Zhang*,
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, PM2.5, NOx, 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.
{"title":"Daily Emission Patterns of Coal-Fired Power Plants in China Based on Multisource Data Fusion","authors":"Nana Wu, Guannan Geng, Xinying Qin, Dan Tong, Yixuan Zheng, Yu Lei and Qiang Zhang*, ","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 CO<sub>2</sub>, PM<sub>2.5</sub>, NO<i><sub>x</sub></i>, and SO<sub>2</sub>, 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":"2 4","pages":"363–372"},"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}
Pub Date : 2022-05-10DOI: 10.1021/acsenvironau.1c00065
Soichi Kikkawa, Kazushi Amamoto, Yu Fujiki, Jun Hirayama, Gen Kato, Hiroki Miura, Tetsuya Shishido and Seiji Yamazoe*,
The phase separation between a liquid amine and the solid carbamic acid exhibited >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 >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.
{"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, Kazushi Amamoto, Yu Fujiki, Jun Hirayama, Gen Kato, Hiroki Miura, Tetsuya Shishido and Seiji Yamazoe*, ","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 >99% CO<sub>2</sub> removal efficiency under a 400 ppm CO<sub>2</sub> flow system using diamines bearing an aminocyclohexyl group. Among them, isophorone diamine [IPDA; 3-(aminomethyl)-3,5,5-trimethylcyclohexylamine] exhibited the highest CO<sub>2</sub> removal efficiency. IPDA reacted with CO<sub>2</sub> in a CO<sub>2</sub>/IPDA molar ratio of ≥1 even in H<sub>2</sub>O as a solvent. The captured CO<sub>2</sub> was completely desorbed at 333 K because the dissolved carbamate ion releases CO<sub>2</sub> at low temperatures. The reusability of IPDA under CO<sub>2</sub> adsorption-and-desorption cycles without degradation, the >99% efficiency kept for 100 h under direct air capture conditions, and the high CO<sub>2</sub> 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":"2 4","pages":"354–362"},"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}
Pub Date : 2022-05-06DOI: 10.1021/acsenvironau.1c00055
Guangjie Zheng, Hang Su and Yafang Cheng*,
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.
{"title":"Revisiting the Key Driving Processes of the Decadal Trend of Aerosol Acidity in the U.S","authors":"Guangjie Zheng, Hang Su and Yafang Cheng*, ","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":"2 4","pages":"346–353"},"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}
Pub Date : 2022-05-02DOI: 10.1021/acsenvironau.1c00061
Yuying Cui, Qingru Wu, Kaiyun Liu, Shuxiao Wang*, Xun Wang, Tao Jiang, Bo Meng, Yurong Wu and Jia Guo,
Rice grain consumption is a primary pathway of human mercury exposure. To trace the source of rice grain mercury in China, we developed a rice paddy mercury transport and transformation model with a grid resolution of 1 km × 1 km by using the unit cell mass conservation method. The simulated total mercury (THg) and methylmercury (MeHg) concentrations in Chinese rice grain ranged from 0.08 to 243.6 and 0.03 to 238.6 μg/kg, respectively, in 2017. Approximately, 81.3% of the national average rice grain THg concentration was due to atmospheric mercury deposition. However, soil heterogeneity, especially the variation in soil mercury, led to the wide rice grain THg distribution across grids. Approximately, 64.8% of the national average rice grain MeHg concentration was due to soil mercury. In situ methylation was the main pathway via which the rice grain MeHg concentration was increased. The coupled impact of high mercury input and methylation potential led to extremely high rice grain MeHg in partial grids among Guizhou province and junctions with surrounding provinces. The spatial variation in soil organic matter significantly impacted the methylation potential among grids, especially in Northeast China. Based on the high-resolution rice grain THg concentration, we identified 0.72% of grids as heavily polluted THg grids (rice grain THg > 20 μg/kg). These grids mainly corresponded to areas in which the human activities of nonferrous metal smelting, cement clinker production, and mercury and other metal mining were conducted. Thus, we recommended measures that are targeted at the control of heavy pollution of rice grain by THg according to the pollution sources. In addition, we observed a wide spatial variation range of MeHg to THg ratios not only in China but also in other regions of the world, which highlights the potential risk of rice intake.
{"title":"Source Apportionment of Speciated Mercury in Chinese Rice Grain Using a High-Resolution Model","authors":"Yuying Cui, Qingru Wu, Kaiyun Liu, Shuxiao Wang*, Xun Wang, Tao Jiang, Bo Meng, Yurong Wu and Jia Guo, ","doi":"10.1021/acsenvironau.1c00061","DOIUrl":"10.1021/acsenvironau.1c00061","url":null,"abstract":"<p >Rice grain consumption is a primary pathway of human mercury exposure. To trace the source of rice grain mercury in China, we developed a rice paddy mercury transport and transformation model with a grid resolution of 1 km × 1 km by using the unit cell mass conservation method. The simulated total mercury (THg) and methylmercury (MeHg) concentrations in Chinese rice grain ranged from 0.08 to 243.6 and 0.03 to 238.6 μg/kg, respectively, in 2017. Approximately, 81.3% of the national average rice grain THg concentration was due to atmospheric mercury deposition. However, soil heterogeneity, especially the variation in soil mercury, led to the wide rice grain THg distribution across grids. Approximately, 64.8% of the national average rice grain MeHg concentration was due to soil mercury. In situ methylation was the main pathway via which the rice grain MeHg concentration was increased. The coupled impact of high mercury input and methylation potential led to extremely high rice grain MeHg in partial grids among Guizhou province and junctions with surrounding provinces. The spatial variation in soil organic matter significantly impacted the methylation potential among grids, especially in Northeast China. Based on the high-resolution rice grain THg concentration, we identified 0.72% of grids as heavily polluted THg grids (rice grain THg > 20 μg/kg). These grids mainly corresponded to areas in which the human activities of nonferrous metal smelting, cement clinker production, and mercury and other metal mining were conducted. Thus, we recommended measures that are targeted at the control of heavy pollution of rice grain by THg according to the pollution sources. In addition, we observed a wide spatial variation range of MeHg to THg ratios not only in China but also in other regions of the world, which highlights the potential risk of rice intake.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":"2 4","pages":"324–335"},"PeriodicalIF":0.0,"publicationDate":"2022-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/32/82/vg1c00061.PMC10125373.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9711677","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}
Pub Date : 2022-04-29DOI: 10.1021/acsenvironau.2c00018
Jinlai Wei, Ting Fang and Manabu Shiraiwa*,
Reactive oxygen species (ROS) play a critical role in the chemical transformation of atmospheric secondary organic aerosols (SOA) and aerosol health effects by causing oxidative stress in vivo. Acidity is an important physicochemical property of atmospheric aerosols, but its effects on the ROS formation from SOA have been poorly characterized. By applying the electron paramagnetic resonance spin-trapping technique and the Diogenes chemiluminescence assay, we find highly distinct radical yields and composition at different pH values in the range of 1–7.4 from SOA generated by oxidation of isoprene, α-terpineol, α-pinene, β-pinene, toluene, and naphthalene. We observe that isoprene SOA has substantial hydroxyl radical (•OH) and organic radical yields at neutral pH, which are 1.5–2 times higher compared to acidic conditions in total radical yields. Superoxide (O2•–) is found to be the dominant species generated by all types of SOAs at lower pH. At neutral pH, α-terpineol SOA exhibits a substantial yield of carbon-centered organic radicals, while no radical formation is observed by aromatic SOA. Further experiments with model compounds show that the decomposition of organic peroxide leading to radical formation may be suppressed at lower pH due to acid-catalyzed rearrangement of peroxides. We also observe 1.5–3 times higher molar yields of hydrogen peroxide (H2O2) in acidic conditions compared to neutral pH by biogenic and aromatic SOA, likely due to enhanced decomposition of α-hydroxyhydroperoxides and quinone redox cycling, respectively. These findings are critical to bridge the gap in understanding ROS formation mechanisms and kinetics in atmospheric and physiological environments.
{"title":"Effects of Acidity on Reactive Oxygen Species Formation from Secondary Organic Aerosols","authors":"Jinlai Wei, Ting Fang and Manabu Shiraiwa*, ","doi":"10.1021/acsenvironau.2c00018","DOIUrl":"10.1021/acsenvironau.2c00018","url":null,"abstract":"<p >Reactive oxygen species (ROS) play a critical role in the chemical transformation of atmospheric secondary organic aerosols (SOA) and aerosol health effects by causing oxidative stress <i>in vivo</i>. Acidity is an important physicochemical property of atmospheric aerosols, but its effects on the ROS formation from SOA have been poorly characterized. By applying the electron paramagnetic resonance spin-trapping technique and the Diogenes chemiluminescence assay, we find highly distinct radical yields and composition at different pH values in the range of 1–7.4 from SOA generated by oxidation of isoprene, α-terpineol, α-pinene, β-pinene, toluene, and naphthalene. We observe that isoprene SOA has substantial hydroxyl radical (<sup>•</sup>OH) and organic radical yields at neutral pH, which are 1.5–2 times higher compared to acidic conditions in total radical yields. Superoxide (O<sub>2</sub><sup>•–</sup>) is found to be the dominant species generated by all types of SOAs at lower pH. At neutral pH, α-terpineol SOA exhibits a substantial yield of carbon-centered organic radicals, while no radical formation is observed by aromatic SOA. Further experiments with model compounds show that the decomposition of organic peroxide leading to radical formation may be suppressed at lower pH due to acid-catalyzed rearrangement of peroxides. We also observe 1.5–3 times higher molar yields of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) in acidic conditions compared to neutral pH by biogenic and aromatic SOA, likely due to enhanced decomposition of α-hydroxyhydroperoxides and quinone redox cycling, respectively. These findings are critical to bridge the gap in understanding ROS formation mechanisms and kinetics in atmospheric and physiological environments.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":"2 4","pages":"336–345"},"PeriodicalIF":0.0,"publicationDate":"2022-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9342606/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40583197","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}
Pub Date : 2022-04-14DOI: 10.1021/acsenvironau.2c00004
Jessica L DeYoung, and , Scott K. Shaw*,
Fungi are prevalent microorganisms in environmental films. Their impacts on the film chemical environment and morphology remains poorly defined. Here we present microscopic and chemical analyses fungi impacts to environmental films over long- and short-time scales. We report bulk properties of films accumulated for 2 months (February and March 2019) and 12 months to contrast short and longer-term effects. Bright field microscopy results show that fungi and fungal-associated aggregates cover close to 14% of the surface after 12 months and include significant numbers of large (tens to hundreds of μm in diameter) particles aggregated with fungal colonies. Data acquired for films accumulated over shorter times (2 months) suggest mechanisms that contribute to these longer-term effects. This is important because the film’s exposed surface will determine what additional material will accumulate over the ensuing weeks or months. A combination of scanning electron microscopy and energy dispersive X-ray spectroscopy provides spatially resolved maps of fugal hypha and nearby elements of interest. We also identify a “nutrient pool” associated with the fungal hypha which extend orthogonally to the growth direction to ca. 50 μm distances. We conclude that fungi have both short-term and long-term effects on the chemistry and morphology of environmental film surfaces. In short, the presence (or absence) of fungi will significantly alter the films’ evolution and should be considered when analyzing environmental film impacts on local processes.
{"title":"Association of Chemical Aggregates and Fungal Moieties Affecting Native Environmental Films","authors":"Jessica L DeYoung, and , Scott K. Shaw*, ","doi":"10.1021/acsenvironau.2c00004","DOIUrl":"10.1021/acsenvironau.2c00004","url":null,"abstract":"<p >Fungi are prevalent microorganisms in environmental films. Their impacts on the film chemical environment and morphology remains poorly defined. Here we present microscopic and chemical analyses fungi impacts to environmental films over long- and short-time scales. We report bulk properties of films accumulated for 2 months (February and March 2019) and 12 months to contrast short and longer-term effects. Bright field microscopy results show that fungi and fungal-associated aggregates cover close to 14% of the surface after 12 months and include significant numbers of large (tens to hundreds of μm in diameter) particles aggregated with fungal colonies. Data acquired for films accumulated over shorter times (2 months) suggest mechanisms that contribute to these longer-term effects. This is important because the film’s exposed surface will determine what additional material will accumulate over the ensuing weeks or months. A combination of scanning electron microscopy and energy dispersive X-ray spectroscopy provides spatially resolved maps of fugal hypha and nearby elements of interest. We also identify a “nutrient pool” associated with the fungal hypha which extend orthogonally to the growth direction to ca. 50 μm distances. We conclude that fungi have both short-term and long-term effects on the chemistry and morphology of environmental film surfaces. In short, the presence (or absence) of fungi will significantly alter the films’ evolution and should be considered when analyzing environmental film impacts on local processes.</p>","PeriodicalId":29801,"journal":{"name":"ACS Environmental Au","volume":"2 4","pages":"310–313"},"PeriodicalIF":0.0,"publicationDate":"2022-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10125300/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9711676","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}