Pub Date : 2024-11-02DOI: 10.1016/j.atmosenv.2024.120913
Huan Li , Ting Zhang , Hui Su , Sui Xin Liu , Ying Qiang Shi , Lu Yao Wang , Dong Dong Xu , Jia Mao Zhou , Zhu Zi Zhao , Qi Yuan Wang , Steven Sai Hang Ho , Yao Qu , Jun Ji Cao
PM2.5 affects air quality, therefore, understanding the mechanism of PM2.5 growth is essential to figure out mitigation measures. Hourly real-time concentrations of water-soluble inorganic ions (WSIIs), including anions and cations, in fine particulate matter (PM2.5) were measured in Baoji, northwest China. During the winter monitoring period, the concentrations of PM2.5 and most WSIIs exhibited similar trends. Mass proportions of SNA [i.e., sulfate (SO42−), nitrate (NO3−), ammonium (NH4+)] in PM2.5 gradually increased with air deterioration, while equivalent ratios of anions to cations also increased. The heterogeneous aqueous reactions and/or gas-phase homogeneous reactions promoted the formation of secondary inorganics, especially during the haze events. Rapid transformations of primary gaseous precursors to secondary pollutants could lead to the substantial formation of SO42− and NO3−. In terms of particle growth rate, the mass proportions of SNA in PM2.5 decreased from General Growth (GG) to Explosive Growth (EG) events. Furthermore, the particle growth rates did not coincide with the pollution levels, while it occurred most frequently during the Transition Period, instead of the Polluted Period. The diurnal variation of SNA at different PM2.5 growth rates has been discussed. The results of the Random Forest (RF) model showed that RH was an important factor for EG of PM2.5, while low RH was a reliable reason for the relatively low mass proportion of SNA. The results of this study could advance our understanding of particle growth and provide scientific evidence to support the establishment of unique air quality control measures under different pollution scenarios in Fenwei Plain, China.
PM2.5会影响空气质量，因此，了解PM2.5的增长机制对于制定减缓措施至关重要。研究人员在中国西北部的宝鸡市测量了细颗粒物（PM2.5）中水溶性无机离子（WSIIs）（包括阴离子和阳离子）的每小时实时浓度。在冬季监测期间，PM2.5 和大多数 WSII 的浓度呈现出相似的趋势。PM2.5 中 SNA [即硫酸盐 (SO42-)、硝酸盐 (NO3-)、铵 (NH4+)]的质量比例随着空气恶化而逐渐增加，同时阴阳离子的当量比也在增加。异相水反应和/或气相均相反应促进了二次无机物的形成，尤其是在雾霾事件期间。一次气态前体物向二次污染物的快速转化可导致 SO42- 和 NO3- 的大量形成。从颗粒增长速度来看，从一般增长（GG）事件到爆炸增长（EG）事件，SNA 在 PM2.5 中的质量比例都有所下降。此外，颗粒增长速度与污染水平并不一致，而在过渡时期而非污染时期出现得最频繁。讨论了不同 PM2.5 增长率下 SNA 的日变化。随机森林（RF）模型的结果表明，相对湿度是 PM2.5 EG 的一个重要因素，而相对湿度低则是 SNA 质量比例相对较低的一个可靠原因。本研究的结果可促进我们对颗粒物增长的理解，并为在中国汾渭平原不同污染情景下建立独特的空气质量控制措施提供科学依据。
{"title":"Factors affecting the different growth rates of PM2.5：Evidence from composition variation, formation mechanisms, and importance analysis of water-soluble inorganic ions with case study in northern China","authors":"Huan Li , Ting Zhang , Hui Su , Sui Xin Liu , Ying Qiang Shi , Lu Yao Wang , Dong Dong Xu , Jia Mao Zhou , Zhu Zi Zhao , Qi Yuan Wang , Steven Sai Hang Ho , Yao Qu , Jun Ji Cao","doi":"10.1016/j.atmosenv.2024.120913","DOIUrl":"10.1016/j.atmosenv.2024.120913","url":null,"abstract":"<div><div>PM<sub>2.5</sub> affects air quality, therefore, understanding the mechanism of PM<sub>2.5</sub> growth is essential to figure out mitigation measures. Hourly real-time concentrations of water-soluble inorganic ions (WSIIs), including anions and cations, in fine particulate matter (PM<sub>2.5</sub>) were measured in Baoji, northwest China. During the winter monitoring period, the concentrations of PM<sub>2.5</sub> and most WSIIs exhibited similar trends. Mass proportions of SNA [i.e., sulfate (SO<sub>4</sub><sup>2−</sup>), nitrate (NO<sub>3</sub><sup>−</sup>), ammonium (NH<sub>4</sub><sup>+</sup>)] in PM<sub>2.5</sub> gradually increased with air deterioration, while equivalent ratios of anions to cations also increased. The heterogeneous aqueous reactions and/or gas-phase homogeneous reactions promoted the formation of secondary inorganics, especially during the haze events. Rapid transformations of primary gaseous precursors to secondary pollutants could lead to the substantial formation of SO<sub>4</sub><sup>2−</sup> and NO<sub>3</sub><sup>−</sup>. In terms of particle growth rate, the mass proportions of SNA in PM<sub>2.5</sub> decreased from General Growth (GG) to Explosive Growth (EG) events. Furthermore, the particle growth rates did not coincide with the pollution levels, while it occurred most frequently during the Transition Period, instead of the Polluted Period. The diurnal variation of SNA at different PM<sub>2.5</sub> growth rates has been discussed. The results of the Random Forest (RF) model showed that RH was an important factor for EG of PM<sub>2.5</sub>, while low RH was a reliable reason for the relatively low mass proportion of SNA. The results of this study could advance our understanding of particle growth and provide scientific evidence to support the establishment of unique air quality control measures under different pollution scenarios in Fenwei Plain, China.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120913"},"PeriodicalIF":4.2,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.atmosenv.2024.120919
Xingxia Kou , Zhen Peng , Yi Gao , Xiao Han , Meigen Zhang
Ozone (O3) pollution, which not only depends on emissions but is also closely related to prevailing meteorological conditions, is a major concern in China. In the context of China's emission controls imposed during the 13th Five-Year Plan, the variations of synoptic circulations and associated summertime O3 variations were investigated during 2016–2020. Different from the common use in previous studies of observations and numerical models, a regional atmospheric composition reanalysis dataset at a refined spatial (45 km) and temporal (1 h) resolution was applied here, in which O3 and its major precursors, emissions, and meteorology were jointly assimilated to reduce the impacts of uncertainty. With this continuous and optimal dataset, the impacts of regional synoptic variations on O3 interannual variability were explored through an objective circulation classification approach during 2016–2020 over China. On the one hand, from the perspective of O3 variability, increasing trends of O3 levels were detected. Compared to the Yangtze River Delta (YRD), Pearl River Delta (PRD), and Sichuan Basin (SCB) with less summer pollution, the Beijing–Tianjin–Hebei (BTH) and Fenwei Plain (FWP) regions had more severe summer O3 pollution with the frequency of days exceeding Grade 3 tends to be around 50%. On the other hand, from the perspective of O3 variability driven by meteorological conditions, obvious interannual variations of synoptic circulation patterns occurred, and about half of type C occurrences were accompanied by O3 pollution episodes in BTH and FWP (i.e., 52.73% and 45.65%), while far fewer pollution episodes occurred with type C in YRD and PRD (i.e., 2.78% and 0.59%). In addition, according to the quantitative assessment of the meteorological contribution, the contribution of interannual variations of synoptic circulations to changing the O3 variability amounted to 13%–31% in BTH, YRD, PRD, FWP, and SCB. Therefore, the interannual variability of O3 from 2016 to 2020 over China was closely linked with the regulations of O3 precursors. This work provides an understanding of O3 variation under the impacts of emission regulations and meteorological conditions over China.
{"title":"Ozone variability and the impacts of associated synoptic patterns over China during summer 2016–2020 based on a regional atmospheric composition reanalysis dataset","authors":"Xingxia Kou , Zhen Peng , Yi Gao , Xiao Han , Meigen Zhang","doi":"10.1016/j.atmosenv.2024.120919","DOIUrl":"10.1016/j.atmosenv.2024.120919","url":null,"abstract":"<div><div>Ozone (O<sub>3</sub>) pollution, which not only depends on emissions but is also closely related to prevailing meteorological conditions, is a major concern in China. In the context of China's emission controls imposed during the 13th Five-Year Plan, the variations of synoptic circulations and associated summertime O<sub>3</sub> variations were investigated during 2016–2020. Different from the common use in previous studies of observations and numerical models, a regional atmospheric composition reanalysis dataset at a refined spatial (45 km) and temporal (1 h) resolution was applied here, in which O<sub>3</sub> and its major precursors, emissions, and meteorology were jointly assimilated to reduce the impacts of uncertainty. With this continuous and optimal dataset, the impacts of regional synoptic variations on O<sub>3</sub> interannual variability were explored through an objective circulation classification approach during 2016–2020 over China. On the one hand, from the perspective of O<sub>3</sub> variability, increasing trends of O<sub>3</sub> levels were detected. Compared to the Yangtze River Delta (YRD), Pearl River Delta (PRD), and Sichuan Basin (SCB) with less summer pollution, the Beijing–Tianjin–Hebei (BTH) and Fenwei Plain (FWP) regions had more severe summer O<sub>3</sub> pollution with the frequency of days exceeding Grade 3 tends to be around 50%. On the other hand, from the perspective of O<sub>3</sub> variability driven by meteorological conditions, obvious interannual variations of synoptic circulation patterns occurred, and about half of type C occurrences were accompanied by O<sub>3</sub> pollution episodes in BTH and FWP (i.e., 52.73% and 45.65%), while far fewer pollution episodes occurred with type C in YRD and PRD (i.e., 2.78% and 0.59%). In addition, according to the quantitative assessment of the meteorological contribution, the contribution of interannual variations of synoptic circulations to changing the O<sub>3</sub> variability amounted to 13%–31% in BTH, YRD, PRD, FWP, and SCB. Therefore, the interannual variability of O<sub>3</sub> from 2016 to 2020 over China was closely linked with the regulations of O<sub>3</sub> precursors. This work provides an understanding of O<sub>3</sub> variation under the impacts of emission regulations and meteorological conditions over China.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120919"},"PeriodicalIF":4.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142586730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-01DOI: 10.1016/j.atmosenv.2024.120915
Zihan Zhu , Xuanlin Du , Don R. Collins
Formation and growth of particles influence the solar radiation budget and the microphysics and properties of clouds. Quantifying the rate at which atmospheric particles grow and understanding the meteorological and chemical controls of that growth are challenging because observations at a fixed location represent a convolution of changes resulting from atmospheric processing and those reflecting the time-varying origin and history of the sampled air. The dual-chamber Captive Aerosol Growth and Evolution (CAGE) chamber system was developed to study particle growth in different environments. Inside the chambers, controlled populations of particles are exposed to an environment in which the air composition and solar intensity track those just outside. Here we present results from the use of the CAGE chamber system at the DOE Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains (SGP) site over two months in the fall of 2021. Both chambers were operated continuously, with monodisperse seed particles injected every several hours and then intermittently measured by a scanning mobility particle sizer. The time dependence of the growth rate measured throughout the study is quantified. The sensitivity of particle growth to the liquid water content of injected seed particles and to the addition of precursor gases was studied by using one chamber as a reference or control and the other as a perturbation chamber.
{"title":"Direct measurement of the growth of small particles in ambient air using captive aerosol chambers","authors":"Zihan Zhu , Xuanlin Du , Don R. Collins","doi":"10.1016/j.atmosenv.2024.120915","DOIUrl":"10.1016/j.atmosenv.2024.120915","url":null,"abstract":"<div><div>Formation and growth of particles influence the solar radiation budget and the microphysics and properties of clouds. Quantifying the rate at which atmospheric particles grow and understanding the meteorological and chemical controls of that growth are challenging because observations at a fixed location represent a convolution of changes resulting from atmospheric processing and those reflecting the time-varying origin and history of the sampled air. The dual-chamber Captive Aerosol Growth and Evolution (CAGE) chamber system was developed to study particle growth in different environments. Inside the chambers, controlled populations of particles are exposed to an environment in which the air composition and solar intensity track those just outside. Here we present results from the use of the CAGE chamber system at the DOE Atmospheric Radiation Measurement (ARM) Program's Southern Great Plains (SGP) site over two months in the fall of 2021. Both chambers were operated continuously, with monodisperse seed particles injected every several hours and then intermittently measured by a scanning mobility particle sizer. The time dependence of the growth rate measured throughout the study is quantified. The sensitivity of particle growth to the liquid water content of injected seed particles and to the addition of precursor gases was studied by using one chamber as a reference or control and the other as a perturbation chamber.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120915"},"PeriodicalIF":4.2,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-31DOI: 10.1016/j.atmosenv.2024.120907
Jithin Kanayankottupoyil, Kuruvilla John
Over the past two decades, significant advancements in shale gas extraction technologies have led to a vast increase in oil and gas production in the Barnett Shale region of North Texas. This study provides a detailed analysis of the trends in air pollutants, such as total nonmethane hydrocarbons (NMHC), linked to oil and gas production changes in the Barnett shale region from 2000 to 2022. The analysis spans urban (Dallas - DAL), semi-urban (Fort Worth - FWNW), and non-urban (Denton - DEN) ambient air quality monitoring sites operated by the Texas Commission on Environmental Quality (TCEQ), highlighting how varying levels of urbanization and industrial activities influence air quality. DEN recorded the highest NMHC concentrations at an average of 210.27 ppb-C, significantly exceeding those at FWNW (83.14 ppb-C) and DAL (62.50 ppb-C). Alkanes were the predominant NMHCs across all sites, forming 96% at DEN, 89% at FWNW, and 67% at DAL. The i/n-pentane ratio at DEN suggests oil and gas activities as the main NMHC source, whereas DAL, and FWNW indicate substantial influences from urban traffic alongside industrial emissions. NMHC concentrations at DEN and FWNW correlated strongly with gas and condensate production, demonstrating a shift from condensate to gas over the study period.
{"title":"Assessing the impact of oil and gas activities on ambient hydrocarbon concentrations in North Texas: A retrospective analysis from 2000 to 2022","authors":"Jithin Kanayankottupoyil, Kuruvilla John","doi":"10.1016/j.atmosenv.2024.120907","DOIUrl":"10.1016/j.atmosenv.2024.120907","url":null,"abstract":"<div><div>Over the past two decades, significant advancements in shale gas extraction technologies have led to a vast increase in oil and gas production in the Barnett Shale region of North Texas. This study provides a detailed analysis of the trends in air pollutants, such as total nonmethane hydrocarbons (NMHC), linked to oil and gas production changes in the Barnett shale region from 2000 to 2022. The analysis spans urban (Dallas - DAL), semi-urban (Fort Worth - FWNW), and non-urban (Denton - DEN) ambient air quality monitoring sites operated by the Texas Commission on Environmental Quality (TCEQ), highlighting how varying levels of urbanization and industrial activities influence air quality. DEN recorded the highest NMHC concentrations at an average of 210.27 ppb-C, significantly exceeding those at FWNW (83.14 ppb-C) and DAL (62.50 ppb-C). Alkanes were the predominant NMHCs across all sites, forming 96% at DEN, 89% at FWNW, and 67% at DAL. The i/n-pentane ratio at DEN suggests oil and gas activities as the main NMHC source, whereas DAL, and FWNW indicate substantial influences from urban traffic alongside industrial emissions. NMHC concentrations at DEN and FWNW correlated strongly with gas and condensate production, demonstrating a shift from condensate to gas over the study period.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120907"},"PeriodicalIF":4.2,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.atmosenv.2024.120909
T. Legros , B. Temime-Roussel , J. Kammer , E. Quivet , H. Wortham , I.M. Reiter , M. Santonja , C. Fernandez , E. Ormeño
Biogenic volatile organic compounds (BVOCs) are crucial for ecosystem functioning, atmospheric chemistry and climate. While modulation of BVOC emissions from living vegetation with biotic and abiotic factors is well documented, how these factors drive soil BVOC emissions remain less understood, particularly in Mediterranean forests. To fill this gap, this pioneer study investigates whether BVOC fluxes from natural soil covered by litter (referred to as forest soil) vary under natural and amplified long-term water stress (35% annual rain exclusion over the past 10 years) in a deciduous oak Mediterranean forest (Quercus pubescens Willd.) compared to natural climate conditions. This aim has only been tackled in a single evergreen Mediterranean forest so far. Using proton transfer reaction time of flight mass spectrometer (PTR-ToF-MS) we also provide, for the first time, a detailed diurnal cycle of soil BVOCs in relation to air temperature, air humidity, and biotic factors including soil respiration and litter content in lignin, cellulose and hemicellulose. The main results revealed that forest soil represents a source of most BVOCs (e.g., acetaldehyde, acetone, acrolein, hexanol, monoterpenes) with maximum values at mid-day (42 μgC.m−2. h−1) in response to higher temperatures while it acts as a clear sink of isoprene. Total soil BVOC emission rates, together with soil respiration, decreased by 43% after a decade of partial rain restriction. These results will contribute to enhance further modeling of soil BVOC emissions under various climate scenarios both at regional and global scales.
{"title":"Decline of soil volatile organic compounds from a Mediterranean deciduous forest under a future drier climate","authors":"T. Legros , B. Temime-Roussel , J. Kammer , E. Quivet , H. Wortham , I.M. Reiter , M. Santonja , C. Fernandez , E. Ormeño","doi":"10.1016/j.atmosenv.2024.120909","DOIUrl":"10.1016/j.atmosenv.2024.120909","url":null,"abstract":"<div><div>Biogenic volatile organic compounds (BVOCs) are crucial for ecosystem functioning, atmospheric chemistry and climate. While modulation of BVOC emissions from living vegetation with biotic and abiotic factors is well documented, how these factors drive soil BVOC emissions remain less understood, particularly in Mediterranean forests. To fill this gap, this pioneer study investigates whether BVOC fluxes from natural soil covered by litter (referred to as forest soil) vary under natural and amplified long-term water stress (35% annual rain exclusion over the past 10 years) in a deciduous oak Mediterranean forest (<em>Quercus pubescens</em> Willd.) compared to natural climate conditions. This aim has only been tackled in a single evergreen Mediterranean forest so far. Using proton transfer reaction time of flight mass spectrometer (PTR-ToF-MS) we also provide, for the first time, a detailed diurnal cycle of soil BVOCs in relation to air temperature, air humidity, and biotic factors including soil respiration and litter content in lignin, cellulose and hemicellulose. The main results revealed that forest soil represents a source of most BVOCs (e.g., acetaldehyde, acetone, acrolein, hexanol, monoterpenes) with maximum values at mid-day (42 μgC.m<sup>−2</sup>. h<sup>−1</sup>) in response to higher temperatures while it acts as a clear sink of isoprene. Total soil BVOC emission rates, together with soil respiration, decreased by 43% after a decade of partial rain restriction. These results will contribute to enhance further modeling of soil BVOC emissions under various climate scenarios both at regional and global scales.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120909"},"PeriodicalIF":4.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.atmosenv.2024.120914
Yuan Cheng , Ying-jie Zhong , Jiu-meng Liu , Xu-bing Cao , Ke-bin He
Fireworks are banned in many Chinese cities but never eliminated, reflecting strong public demand on this traditional activity for festival celebrations. On the other hand, the assessment of firework contributions to air pollution remains vague, raising concerns on the necessity of the mandatory bans. Here we investigated the characteristics of firework episodes in a megacity in Northeast China, based on field campaigns conducted in four successive winters during 2018–2022. Although prohibited, the firework influences remained evident during the Chinese New Year periods, as suggested by the enhancements of water-soluble potassium (K+). In addition, significant annual variations were identified for the firework episodes, with the following features observed. First, the firework-induced enrichment ratios of K+ and chloride exhibited increasing trends across years, climbing from 4.4 to 8.6 and from 1.7 to 2.9, respectively. Second, the enrichment ratio of sulfate dropped from 2.8 to 1.6, indicating that the firework contributions to sulfate decreased but remained considerable. Third, fireworks turned into an unimportant source for organic carbon and nitrate in the most recent winter of 2021–2022, with enrichment ratios of ∼1 for both species. Fourth, the firework-driven increases in fine particle concentration were as high as ∼100% for the two winters during 2019–2021, whereas the increase dropped sharply to ∼30% for 2021–2022. These variations were in line with the promotion of environmentally friendly fireworks. Our results indicated that the air pollution caused by fireworks could be reduced substantially by advanced manufacturing technologies and thus it is time to rethink the firework bans.
{"title":"Significant annual variations of firework-impacted aerosols in Northeast China: Implications for rethinking the firework bans","authors":"Yuan Cheng , Ying-jie Zhong , Jiu-meng Liu , Xu-bing Cao , Ke-bin He","doi":"10.1016/j.atmosenv.2024.120914","DOIUrl":"10.1016/j.atmosenv.2024.120914","url":null,"abstract":"<div><div>Fireworks are banned in many Chinese cities but never eliminated, reflecting strong public demand on this traditional activity for festival celebrations. On the other hand, the assessment of firework contributions to air pollution remains vague, raising concerns on the necessity of the mandatory bans. Here we investigated the characteristics of firework episodes in a megacity in Northeast China, based on field campaigns conducted in four successive winters during 2018–2022. Although prohibited, the firework influences remained evident during the Chinese New Year periods, as suggested by the enhancements of water-soluble potassium (K<sup>+</sup>). In addition, significant annual variations were identified for the firework episodes, with the following features observed. First, the firework-induced enrichment ratios of K<sup>+</sup> and chloride exhibited increasing trends across years, climbing from 4.4 to 8.6 and from 1.7 to 2.9, respectively. Second, the enrichment ratio of sulfate dropped from 2.8 to 1.6, indicating that the firework contributions to sulfate decreased but remained considerable. Third, fireworks turned into an unimportant source for organic carbon and nitrate in the most recent winter of 2021–2022, with enrichment ratios of ∼1 for both species. Fourth, the firework-driven increases in fine particle concentration were as high as ∼100% for the two winters during 2019–2021, whereas the increase dropped sharply to ∼30% for 2021–2022. These variations were in line with the promotion of environmentally friendly fireworks. Our results indicated that the air pollution caused by fireworks could be reduced substantially by advanced manufacturing technologies and thus it is time to rethink the firework bans.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120914"},"PeriodicalIF":4.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-30DOI: 10.1016/j.atmosenv.2024.120908
Dongkyu Park , Byung In Lim
As studies regarding the positive effect of Low Emission Zones (LEZs) and people's risk perception about air pollution have increased, more powerful and specific traffic regulation policies have been required. London is the first city in the world to implement an Ultra-low Emission Zone (ULEZ) in addition to the existing LEZ. Benchmarking London's ULEZ, a ULEZ policy was implemented in Seoul, South Korea on December 1, 2019. The goal of the policy is to improve air quality by prohibiting entry of vehicles registered nationwide into Seoul's ULEZ that do not meet a specific emission standard including diesel, gasoline, and LPG fuel-based vehicles. This study analyzed the effect of Seoul's ULEZ policy on the five major atmospheric pollutants (PM2.5, PM10, NO2, CO, SO2, O3) concentration in the zone, particularly focusing on PM2.5 concentration. The analysis employs Difference-in-Differences (DD) approach, comparing data from one year before and after the policy's implementation on December 1, 2019. The findings indicate that Seoul's ULEZ policy resulted in a 9.8% increase in PM2.5 concentrations. Conversely, the policy led to reductions in PM10, NO2, CO, and SO2 concentrations by 12.0%, 17.3%, 5.9%, and 10.8%, respectively, while the effect on O3 was statistically insignificant. These empirical results suggest that the ULEZ may need to incorporate more stringent emission standards, expand its coverage, or introduce additional measures to address the unintended increase in PM2.5 concentration.
{"title":"The effect of the ultra-low emission zone on PM2.5 concentration in Seoul, South Korea","authors":"Dongkyu Park , Byung In Lim","doi":"10.1016/j.atmosenv.2024.120908","DOIUrl":"10.1016/j.atmosenv.2024.120908","url":null,"abstract":"<div><div>As studies regarding the positive effect of Low Emission Zones (LEZs) and people's risk perception about air pollution have increased, more powerful and specific traffic regulation policies have been required. London is the first city in the world to implement an Ultra-low Emission Zone (ULEZ) in addition to the existing LEZ. Benchmarking London's ULEZ, a ULEZ policy was implemented in Seoul, South Korea on December 1, 2019. The goal of the policy is to improve air quality by prohibiting entry of vehicles registered nationwide into Seoul's ULEZ that do not meet a specific emission standard including diesel, gasoline, and LPG fuel-based vehicles. This study analyzed the effect of Seoul's ULEZ policy on the five major atmospheric pollutants (PM2.5, PM10, NO2, CO, SO2, O3) concentration in the zone, particularly focusing on PM2.5 concentration. The analysis employs Difference-in-Differences (DD) approach, comparing data from one year before and after the policy's implementation on December 1, 2019. The findings indicate that Seoul's ULEZ policy resulted in a 9.8% increase in PM2.5 concentrations. Conversely, the policy led to reductions in PM10, NO2, CO, and SO2 concentrations by 12.0%, 17.3%, 5.9%, and 10.8%, respectively, while the effect on O3 was statistically insignificant. These empirical results suggest that the ULEZ may need to incorporate more stringent emission standards, expand its coverage, or introduce additional measures to address the unintended increase in PM2.5 concentration.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120908"},"PeriodicalIF":4.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.atmosenv.2024.120897
Zhaolian Ye , Dandan Hu , Zixuan Wang , Hui Wang , Xinlei Ge
Most aqueous oxidation studies focus on single model precursors, while the photochemical aging of actual water soluble organic matter (WSOM) in particles emitted from biomass burning remains poorly understood. In this study, gas chromatography-mass spectrometry (GC/MS) was first used to analyze the WSOM in smoke particles emitted from three crop straws burning. The results show that the dominant WSOM in three crop straws (CS) smoke are phenolic substances with small differences. Aqueous photochemical aging of WSOM in CS smoke was investigated under simulated sunlight exposure. High-resolution aerosol mass spectrometry (HR-AMS) analyzed aqueous secondary organic aerosol (aqSOA) and it was found that the oxidation degree of aqSOA increased with prolonged aging. No obvious increase in the abundance of N-containing organic ions was observed over the course of aqueous aging. As aqueous aging progresses, the pH of the solution gradually decreases, accompanied by the continuous generation of organic acids. Studies on dithiothreitol (DTT) activity indicate that the impact of aqueous photochemical aging on health is not significant.
The solution after photoaging shows relatively lower light absorption ability than the initial solution. The aqueous photochemical aging also led to a gradual reduction of fluorescence at excitation/emission = 250–260 nm/350 nm (protein-like substances) for CS smoke WSOM, suggesting the significant degradation of chromophores. However, three-dimensional excitation-emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC) revealed that aqueous aged CS smoke WSOM contains compounds with high humification index, confirming that the fluorophore composition is altered by aqueous aging. The humic-like substance (HULIS) concentration increased for the first 3 h and then decreased, closely matching the pattern of a new fluorescence peak. Finally, GC/MS analysis of the products indicated that there was obvious decline in proportion of methoxyphenol. The results of this study are important for understanding the aqueous-phase oxidation reactions of CS smoke WSOM in the atmosphere and their light-absorption characteristics and health impacts.
{"title":"Aqueous photochemical aging of water-soluble smoke particles from crop straws burning","authors":"Zhaolian Ye , Dandan Hu , Zixuan Wang , Hui Wang , Xinlei Ge","doi":"10.1016/j.atmosenv.2024.120897","DOIUrl":"10.1016/j.atmosenv.2024.120897","url":null,"abstract":"<div><div>Most aqueous oxidation studies focus on single model precursors, while the photochemical aging of actual water soluble organic matter (WSOM) in particles emitted from biomass burning remains poorly understood. In this study, gas chromatography-mass spectrometry (GC/MS) was first used to analyze the WSOM in smoke particles emitted from three crop straws burning. The results show that the dominant WSOM in three crop straws (CS) smoke are phenolic substances with small differences. Aqueous photochemical aging of WSOM in CS smoke was investigated under simulated sunlight exposure. High-resolution aerosol mass spectrometry (HR-AMS) analyzed aqueous secondary organic aerosol (aqSOA) and it was found that the oxidation degree of aqSOA increased with prolonged aging. No obvious increase in the abundance of N-containing organic ions was observed over the course of aqueous aging. As aqueous aging progresses, the pH of the solution gradually decreases, accompanied by the continuous generation of organic acids. Studies on dithiothreitol (DTT) activity indicate that the impact of aqueous photochemical aging on health is not significant.</div><div>The solution after photoaging shows relatively lower light absorption ability than the initial solution. The aqueous photochemical aging also led to a gradual reduction of fluorescence at excitation/emission = 250–260 nm/350 nm (protein-like substances) for CS smoke WSOM, suggesting the significant degradation of chromophores. However, three-dimensional excitation-emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC) revealed that aqueous aged CS smoke WSOM contains compounds with high humification index, confirming that the fluorophore composition is altered by aqueous aging. The humic-like substance (HULIS) concentration increased for the first 3 h and then decreased, closely matching the pattern of a new fluorescence peak. Finally, GC/MS analysis of the products indicated that there was obvious decline in proportion of methoxyphenol. The results of this study are important for understanding the aqueous-phase oxidation reactions of CS smoke WSOM in the atmosphere and their light-absorption characteristics and health impacts.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120897"},"PeriodicalIF":4.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.atmosenv.2024.120898
Fatima Al Ali , Vincent Gaudion , Alexandre Tomas , Nicolas Houzel , Cécile Cœur , Manolis N. Romanias
<div><div>In this study, the gas phase reaction of NO<sub>3</sub> radical with three furanoids, furan (F), 2-methylfuran (2-MF) and 2,5-dimethylfuran (2,5-DMF) were investigated using a relative rate method in a temperature regulated atmospheric simulation chamber (THALAMOS). As part of this study, the temperature dependence of two monoterpenes, α-pinene (α-P) and 2-carene (2-C), that were used as reference molecules, is also reported. The kinetic measurements were performed in the range of 263–373 K, atmospheric pressure using zero air as bath gas. The reaction was followed using Selected ion flow tube mass spectrometry (SIFT-MS) to monitor in real time the mixing ratios of the investigated species. The corresponding Arrhenius expressions obtained were:</div><div><span><math><mrow><msub><mi>k</mi><mrow><mi>α</mi><mo>−</mo><mi>P</mi><mo>+</mo><mi>N</mi><mi>O</mi><mn>3</mn></mrow></msub><mrow><mo>(</mo><mrow><mn>263</mn><mo>−</mo><mn>378</mn><mspace></mspace><mi>K</mi></mrow><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><mrow><mn>1.32</mn><mo>±</mo><mn>0.16</mn></mrow><mo>)</mo></mrow><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup><mo>×</mo><msup><mi>e</mi><mfrac><mrow><mn>462</mn><mo>±</mo><mn>70</mn></mrow><mi>T</mi></mfrac></msup><mspace></mspace><msup><mtext>cm</mtext><mn>3</mn></msup><mspace></mspace><msup><mtext>molecule</mtext><mrow><mo>‐</mo><mo>1</mo></mrow></msup><mspace></mspace><msup><mi>s</mi><mrow><mo>‐</mo><mn>1</mn></mrow></msup></mrow></math></span>.</div><div><span><math><msub><mi>k</mi><mrow><mn>2</mn><mo>−</mo><mi>C</mi><mo>+</mo><mi>N</mi><mi>O</mi><mn>3</mn></mrow></msub><mfenced><mrow><mn>296</mn><mspace></mspace><mo>–</mo><mspace></mspace><mn>433</mn><mspace></mspace><mi>K</mi></mrow></mfenced><mo>=</mo><mfenced><mrow><mn>8.77</mn><mo>±</mo><mn>2</mn><mo>.</mo><mn>71</mn></mrow></mfenced><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup><mo>×</mo><msup><mi>e</mi><mfrac><mrow><mn>904</mn><mo>±</mo><mn>96</mn></mrow><mi>T</mi></mfrac></msup><mspace></mspace><msup><mtext>cm</mtext><mn>3</mn></msup><mspace></mspace><msup><mtext>molecule</mtext><mrow><mo>‐</mo><mo>1</mo></mrow></msup><mspace></mspace><msup><mi>s</mi><mrow><mo>‐</mo><mo>1</mo></mrow></msup></math></span>.</div><div><span><math><msub><mi>k</mi><mrow><mi>F</mi><mo>+</mo><mi>N</mi><mi>O</mi><mn>3</mn></mrow></msub><mfenced><mrow><mn>263</mn><mo>−</mo><mn>353</mn><mspace></mspace><mi>K</mi></mrow></mfenced><mo>=</mo><mfenced><mrow><mn>7.55</mn><mo>±</mo><mn>1</mn><mo>.</mo><mn>96</mn></mrow></mfenced><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup><mo>×</mo><msup><mi>e</mi><mfrac><mfenced><mrow><mn>254</mn><mo>±</mo><mn>79</mn></mrow></mfenced><mi>T</mi></mfrac></msup><mspace></mspace><msup><mtext>cm</mtext><mn>3</mn></msup><mspace></mspace><msup><mtext>molecule</mtext><mrow><mo>‐</mo><mo>1</mo></mrow></msup><mspace></mspace><msup><mi>s</mi><mrow><mo>‐</mo><mo>1</mo></mrow></msup></math></span>.</div><div><span>
{"title":"Nighttime chemistry of furanoids and terpenes: Temperature dependent kinetics with NO3 radicals and insights into the reaction mechanism","authors":"Fatima Al Ali , Vincent Gaudion , Alexandre Tomas , Nicolas Houzel , Cécile Cœur , Manolis N. Romanias","doi":"10.1016/j.atmosenv.2024.120898","DOIUrl":"10.1016/j.atmosenv.2024.120898","url":null,"abstract":"<div><div>In this study, the gas phase reaction of NO<sub>3</sub> radical with three furanoids, furan (F), 2-methylfuran (2-MF) and 2,5-dimethylfuran (2,5-DMF) were investigated using a relative rate method in a temperature regulated atmospheric simulation chamber (THALAMOS). As part of this study, the temperature dependence of two monoterpenes, α-pinene (α-P) and 2-carene (2-C), that were used as reference molecules, is also reported. The kinetic measurements were performed in the range of 263–373 K, atmospheric pressure using zero air as bath gas. The reaction was followed using Selected ion flow tube mass spectrometry (SIFT-MS) to monitor in real time the mixing ratios of the investigated species. The corresponding Arrhenius expressions obtained were:</div><div><span><math><mrow><msub><mi>k</mi><mrow><mi>α</mi><mo>−</mo><mi>P</mi><mo>+</mo><mi>N</mi><mi>O</mi><mn>3</mn></mrow></msub><mrow><mo>(</mo><mrow><mn>263</mn><mo>−</mo><mn>378</mn><mspace></mspace><mi>K</mi></mrow><mo>)</mo></mrow><mo>=</mo><mrow><mo>(</mo><mrow><mn>1.32</mn><mo>±</mo><mn>0.16</mn></mrow><mo>)</mo></mrow><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup><mo>×</mo><msup><mi>e</mi><mfrac><mrow><mn>462</mn><mo>±</mo><mn>70</mn></mrow><mi>T</mi></mfrac></msup><mspace></mspace><msup><mtext>cm</mtext><mn>3</mn></msup><mspace></mspace><msup><mtext>molecule</mtext><mrow><mo>‐</mo><mo>1</mo></mrow></msup><mspace></mspace><msup><mi>s</mi><mrow><mo>‐</mo><mn>1</mn></mrow></msup></mrow></math></span>.</div><div><span><math><msub><mi>k</mi><mrow><mn>2</mn><mo>−</mo><mi>C</mi><mo>+</mo><mi>N</mi><mi>O</mi><mn>3</mn></mrow></msub><mfenced><mrow><mn>296</mn><mspace></mspace><mo>–</mo><mspace></mspace><mn>433</mn><mspace></mspace><mi>K</mi></mrow></mfenced><mo>=</mo><mfenced><mrow><mn>8.77</mn><mo>±</mo><mn>2</mn><mo>.</mo><mn>71</mn></mrow></mfenced><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup><mo>×</mo><msup><mi>e</mi><mfrac><mrow><mn>904</mn><mo>±</mo><mn>96</mn></mrow><mi>T</mi></mfrac></msup><mspace></mspace><msup><mtext>cm</mtext><mn>3</mn></msup><mspace></mspace><msup><mtext>molecule</mtext><mrow><mo>‐</mo><mo>1</mo></mrow></msup><mspace></mspace><msup><mi>s</mi><mrow><mo>‐</mo><mo>1</mo></mrow></msup></math></span>.</div><div><span><math><msub><mi>k</mi><mrow><mi>F</mi><mo>+</mo><mi>N</mi><mi>O</mi><mn>3</mn></mrow></msub><mfenced><mrow><mn>263</mn><mo>−</mo><mn>353</mn><mspace></mspace><mi>K</mi></mrow></mfenced><mo>=</mo><mfenced><mrow><mn>7.55</mn><mo>±</mo><mn>1</mn><mo>.</mo><mn>96</mn></mrow></mfenced><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>13</mn></mrow></msup><mo>×</mo><msup><mi>e</mi><mfrac><mfenced><mrow><mn>254</mn><mo>±</mo><mn>79</mn></mrow></mfenced><mi>T</mi></mfrac></msup><mspace></mspace><msup><mtext>cm</mtext><mn>3</mn></msup><mspace></mspace><msup><mtext>molecule</mtext><mrow><mo>‐</mo><mo>1</mo></mrow></msup><mspace></mspace><msup><mi>s</mi><mrow><mo>‐</mo><mo>1</mo></mrow></msup></math></span>.</div><div><span>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120898"},"PeriodicalIF":4.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.atmosenv.2024.120896
Yesol Cha , Jong-Jae Lee , Chul Han Song , Soontae Kim , Rokjin J. Park , Myong-In Lee , Jung-Hun Woo , Jae-Ho Choi , Kangho Bae , Jinhyeok Yu , Eunhye Kim , Hyeonmin Kim , Seung-Hee Lee , Jinseok Kim , Lim-Seok Chang , Kwon-ho Jeon , Chang-Keun Song
The international field campaign, GMAP/SIJAQ 2021, was conducted in Korea from October 18th to November 25th to enhance the performance and validation of the Geostationary Environment Monitoring Spectrometer (GEMS) products algorithm and obtain a better understanding of the current air pollution status of the Korean Peninsula. Five chemical transport models (CTMs), including CMAQ, CMAQ-GIST, CAMx, WRF-Chem, and WRF GEOS-Chem, were utilized during the campaign to assist in organizing the observation plan and identifying changes in pollutant concentrations and their spatiotemporal distribution in Korea following the Korea–United States Air Quality (KORUS-AQ) 2016. In this study, we evaluated the forecasting performance, strengths, and limitations of these five CTMs and their ensemble in simulating air quality. Intensive measurement data and intercomparisons were employed to explain discrepancies between observed and simulated results. A comparison of the CTM ensemble results for PM2.5 and various gaseous pollutants between the current GMAP/SIJAQ 2021 and previous KORUS-AQ 2016 campaigns showed the R-value for the total mass PM2.5 concentration increased from 0.88 to 0.94. This improvement is related to CTM updates, including the emission inventory and better reproductions of the concentrations of gaseous species. However, the models consistently underestimated carbon monoxide (CO) concentrations, similar to the results from KORUS-AQ. This finding still suggests a further challenge that requires consideration of missing anthropogenic sources. The results of the ensemble model agreed well with the chemical composition of PM2.5 observed at the intensive monitoring station. However, for NO3− and NH4+, discrepancies were primarily due to inaccuracies in the meteorological inputs, such as precipitation, relative humidity (RH), and nighttime planetary boundary layer height (PBLH) in the CTMs. Hence, all models overestimated the concentration of elemental carbon (EC), therefore, it is necessary to revise EC emissions in the SIJAQv2 inventory, as these apply to unusual levels recorded in Seoul during the reference year of 2018.
{"title":"Investigating uncertainties in air quality models used in GMAP/SIJAQ 2021 field campaign: General performance of different models and ensemble results","authors":"Yesol Cha , Jong-Jae Lee , Chul Han Song , Soontae Kim , Rokjin J. Park , Myong-In Lee , Jung-Hun Woo , Jae-Ho Choi , Kangho Bae , Jinhyeok Yu , Eunhye Kim , Hyeonmin Kim , Seung-Hee Lee , Jinseok Kim , Lim-Seok Chang , Kwon-ho Jeon , Chang-Keun Song","doi":"10.1016/j.atmosenv.2024.120896","DOIUrl":"10.1016/j.atmosenv.2024.120896","url":null,"abstract":"<div><div>The international field campaign, GMAP/SIJAQ 2021, was conducted in Korea from October 18th to November 25th to enhance the performance and validation of the Geostationary Environment Monitoring Spectrometer (GEMS) products algorithm and obtain a better understanding of the current air pollution status of the Korean Peninsula. Five chemical transport models (CTMs), including CMAQ, CMAQ-GIST, CAMx, WRF-Chem, and WRF GEOS-Chem, were utilized during the campaign to assist in organizing the observation plan and identifying changes in pollutant concentrations and their spatiotemporal distribution in Korea following the Korea–United States Air Quality (KORUS-AQ) 2016. In this study, we evaluated the forecasting performance, strengths, and limitations of these five CTMs and their ensemble in simulating air quality. Intensive measurement data and intercomparisons were employed to explain discrepancies between observed and simulated results. A comparison of the CTM ensemble results for PM<sub>2.5</sub> and various gaseous pollutants between the current GMAP/SIJAQ 2021 and previous KORUS-AQ 2016 campaigns showed the R-value for the total mass PM<sub>2.5</sub> concentration increased from 0.88 to 0.94. This improvement is related to CTM updates, including the emission inventory and better reproductions of the concentrations of gaseous species. However, the models consistently underestimated carbon monoxide (CO) concentrations, similar to the results from KORUS-AQ. This finding still suggests a further challenge that requires consideration of missing anthropogenic sources. The results of the ensemble model agreed well with the chemical composition of PM<sub>2.5</sub> observed at the intensive monitoring station. However, for NO<sub>3</sub><sup>−</sup> and NH<sub>4</sub><sup>+</sup>, discrepancies were primarily due to inaccuracies in the meteorological inputs, such as precipitation, relative humidity (RH), and nighttime planetary boundary layer height (PBLH) in the CTMs. Hence, all models overestimated the concentration of elemental carbon (EC), therefore, it is necessary to revise EC emissions in the SIJAQv2 inventory, as these apply to unusual levels recorded in Seoul during the reference year of 2018.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"340 ","pages":"Article 120896"},"PeriodicalIF":4.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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