Pub Date : 2025-11-19DOI: 10.1016/j.atmosenv.2025.121698
Jeonghwan Kim , Jiseon Lee , Chisung Yun , Meehye Lee , Hyunmin Lee , Kwangrae Kim , Hee Sun Lee , Limseok Chang , Gangwoong Lee
Continuous measurements of dinitrogen pentoxide (N2O5) and nitrate radical (NO3) were conducted at an urban site in Seoul during the ASIA-AQ campaign (February–March 2024). Observed concentrations of N2O5 and NO3 ranged from the detection limit to 1047 and 9.7 pptv, with mean values of 58.7 and 0.4 pptv, respectively. To investigate nocturnal nitrate chemistry, a one-dimensional (1-D) model was applied using in-situ constraints. The model yielded a representative N2O5 uptake coefficient (γN2O5) of 0.021 (95 % confidence interval: 0.015–0.029), indicating significant heterogeneous loss. While the model successfully reproduced the general diurnal variations of key species, it tended to underestimate concentrations of N2O5 and NO3 during pre-dawn hours (01:00 to 04:00 Local Time) under the influence of mountain breezes. Simulations revealed the accumulation of high concentrations of NO3 and N2O5 in the upper residual layer, with heterogeneous N2O5 hydrolysis contributing 10.2–19.5 % of the total column nitric acid (HNO3) production but only 2.5–5.5 % near the surface. Although surface contributions were limited, vertical profiles indicated that this pathway becomes important when NO3 and N2O5 in the residual layer are transported downward. Such downward transport, driven by mountain breezes, enhanced early morning NO3 and N2O5 concentrations by a factor of two to three. These findings highlight the important role of nocturnal vertical transport in nitrate radicals budgets in complex urban areas, including Seoul and other megacities.
{"title":"Nocturnal N2O5 and NO3 chemistry and its impact on wintertime HNO3 in Seoul during ASIA-AQ campaign","authors":"Jeonghwan Kim , Jiseon Lee , Chisung Yun , Meehye Lee , Hyunmin Lee , Kwangrae Kim , Hee Sun Lee , Limseok Chang , Gangwoong Lee","doi":"10.1016/j.atmosenv.2025.121698","DOIUrl":"10.1016/j.atmosenv.2025.121698","url":null,"abstract":"<div><div>Continuous measurements of dinitrogen pentoxide (N<sub>2</sub>O<sub>5</sub>) and nitrate radical (NO<sub>3</sub>) were conducted at an urban site in Seoul during the ASIA-AQ campaign (February–March 2024). Observed concentrations of N<sub>2</sub>O<sub>5</sub> and NO<sub>3</sub> ranged from the detection limit to 1047 and 9.7 pptv, with mean values of 58.7 and 0.4 pptv, respectively. To investigate nocturnal nitrate chemistry, a one-dimensional (1-D) model was applied using in-situ constraints. The model yielded a representative N<sub>2</sub>O<sub>5</sub> uptake coefficient (γN<sub>2</sub>O<sub>5</sub>) of 0.021 (95 % confidence interval: 0.015–0.029), indicating significant heterogeneous loss. While the model successfully reproduced the general diurnal variations of key species, it tended to underestimate concentrations of N<sub>2</sub>O<sub>5</sub> and NO<sub>3</sub> during pre-dawn hours (01:00 to 04:00 Local Time) under the influence of mountain breezes. Simulations revealed the accumulation of high concentrations of NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> in the upper residual layer, with heterogeneous N<sub>2</sub>O<sub>5</sub> hydrolysis contributing 10.2–19.5 % of the total column nitric acid (HNO<sub>3</sub>) production but only 2.5–5.5 % near the surface. Although surface contributions were limited, vertical profiles indicated that this pathway becomes important when NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> in the residual layer are transported downward. Such downward transport, driven by mountain breezes, enhanced early morning NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> concentrations by a factor of two to three. These findings highlight the important role of nocturnal vertical transport in nitrate radicals budgets in complex urban areas, including Seoul and other megacities.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121698"},"PeriodicalIF":3.7,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615590","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 : 2025-11-19DOI: 10.1016/j.atmosenv.2025.121701
Saravanan Kanagaratnam , Raghu Betha , Kaitlyn M. McKinney , Anastasia Hewitt , Lorena A. Zanandreis , Srijan Aggarwal , Dominique Pride , Sailesh N. Behera
North Pole, Alaska, experiences severe wintertime air quality degradation driven by elevated residential biomass burning and persistent meteorological inversions. However, the comprehensive characterization and underlying drivers of fine particulate matter (PM2.5) in this region remain understudied. This study integrates data from four consecutive winter campaigns, combining pollutant measurements and meteorological variables to assess the key drivers of the PM2.5 and its carbonaceous components. Major factors influencing the PM2.5 threshold exceedances were identified using generalized ordered logit regression (GOLR) with an overall accuracy of 67.51 %. Colder temperatures, low absolute pressure, higher relative humidity (RH), elevated Absorption Ångström Exponent (AAE), and zonal component of wind (east to west wind direction), fireworks, and specific temporal patterns (afternoon, evening, and night hours), along with their interactions, were associated with higher PM2.5 levels (>55.4 μg/m3). Mean organic carbon to black carbon ratios (OC/BC) ranged from 8.25 to 10.83 across the four campaigns, consistent with influence from both biomass burning and secondary organic aerosol (SOA) formation. High mean and median OC/BC ratios, strong correlations (R2 = 0.73–0.97) between PM2.5 and total carbon (TC), and weak to strong correlations (R2 = 0.47–0.87) between PM2.5 and black carbon (BC), highlighted source influence and atmospheric processing. The larger variability in OC/BC, ranging from 0.84 to 70.95, indicates the mixing of different primary sources and considerable SOA formation or atmospheric aging. Inter-winter variability in PM2.5 concentrations was primarily driven by local emissions, meteorological conditions including temperature, winds, and planetary boundary layer height (PBLH), and pollutant dispersion patterns, with minimal influence from long-range transport. AAE consistently showed positive associations with elevated PM2.5 levels, indicating biomass burning was an important source during the campaigns.
{"title":"Drivers of extreme wintertime PM2.5 pollution levels in North Pole, Alaska: A generalized ordered logit regression analysis","authors":"Saravanan Kanagaratnam , Raghu Betha , Kaitlyn M. McKinney , Anastasia Hewitt , Lorena A. Zanandreis , Srijan Aggarwal , Dominique Pride , Sailesh N. Behera","doi":"10.1016/j.atmosenv.2025.121701","DOIUrl":"10.1016/j.atmosenv.2025.121701","url":null,"abstract":"<div><div>North Pole, Alaska, experiences severe wintertime air quality degradation driven by elevated residential biomass burning and persistent meteorological inversions. However, the comprehensive characterization and underlying drivers of fine particulate matter (PM<sub>2.5</sub>) in this region remain understudied. This study integrates data from four consecutive winter campaigns, combining pollutant measurements and meteorological variables to assess the key drivers of the PM<sub>2.5</sub> and its carbonaceous components. Major factors influencing the PM<sub>2.5</sub> threshold exceedances were identified using generalized ordered logit regression (GOLR) with an overall accuracy of 67.51 %. Colder temperatures, low absolute pressure, higher relative humidity (RH), elevated Absorption Ångström Exponent (AAE), and zonal component of wind (east to west wind direction), fireworks, and specific temporal patterns (afternoon, evening, and night hours), along with their interactions, were associated with higher PM<sub>2.5</sub> levels (>55.4 μg/m<sup>3</sup>). Mean organic carbon to black carbon ratios (OC/BC) ranged from 8.25 to 10.83 across the four campaigns, consistent with influence from both biomass burning and secondary organic aerosol (SOA) formation. High mean and median OC/BC ratios, strong correlations (R<sup>2</sup> = 0.73–0.97) between PM<sub>2.5</sub> and total carbon (TC), and weak to strong correlations (R<sup>2</sup> = 0.47–0.87) between PM<sub>2.5</sub> and black carbon (BC), highlighted source influence and atmospheric processing. The larger variability in OC/BC, ranging from 0.84 to 70.95, indicates the mixing of different primary sources and considerable SOA formation or atmospheric aging. Inter-winter variability in PM<sub>2.5</sub> concentrations was primarily driven by local emissions, meteorological conditions including temperature, winds, and planetary boundary layer height (PBLH), and pollutant dispersion patterns, with minimal influence from long-range transport. AAE consistently showed positive associations with elevated PM<sub>2.5</sub> levels, indicating biomass burning was an important source during the campaigns.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121701"},"PeriodicalIF":3.7,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145615589","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 : 2025-11-18DOI: 10.1016/j.atmosenv.2025.121692
Min-Young Choi , Jinseok Kim , Hyejung Hu , Jiyi Lee , Ahn Lee , Jaeyoon Lee , Younha Kim , Jung-Hun Woo
In this study, an emission inventory of 16 PAHs, including 7 carcinogenic PAHs, was developed using the latest data for Korea. The study incorporated emission sources that had been omitted in previous studies. PAHs emissions were estimated by region (at city, county, and district levels) and sector to enable a more precise identification of the emission status in Korea. The total annual emission of 16 PAHs in Korea in 2017 was 1259.7 Mg, with 7 PAHs contributing 41.77 Mg. The major sector of the emissions of the 16 PAHs was industrial process (33.5 %). For the 7 PAHs, other area source was the major emission sector (38.8 %), mainly due to wildfires. In terms of regional aspects, regions with high Industrial Process activities such as ULSAN, JEONNAM, CHUNGNAM, along with GYEONGGI, a major hub for Korean Energy Transport and Storage, showed the highest emissions. The developed emission inventory was intercompared with other inventories, ensuring the appropriate application of emission factors for each emission sector. Especially, it was found that the Korean PAH emissions reported in EDGARv6.0 were 1.9–5.1 times different from those estimated in this study, depending on the pollutant. It was discovered that the emission factors in the residential sector in EDGARv6.0 may differ from the actual emission characteristics in Korea. The PAHs emission inventory developed in this study is anticipated to be used for the establishment and regulation of PAHs policies in Korea. Furthermore, the research results are expected to be essential reference material for refining the emission inventory of PAHs for Korea, which is used in atmospheric transport modeling.
{"title":"Development of a Polycyclic Aromatic Hydrocarbons (PAHs) emission inventory in Korea","authors":"Min-Young Choi , Jinseok Kim , Hyejung Hu , Jiyi Lee , Ahn Lee , Jaeyoon Lee , Younha Kim , Jung-Hun Woo","doi":"10.1016/j.atmosenv.2025.121692","DOIUrl":"10.1016/j.atmosenv.2025.121692","url":null,"abstract":"<div><div>In this study, an emission inventory of 16 PAHs, including 7 carcinogenic PAHs, was developed using the latest data for Korea. The study incorporated emission sources that had been omitted in previous studies. PAHs emissions were estimated by region (at city, county, and district levels) and sector to enable a more precise identification of the emission status in Korea. The total annual emission of 16 PAHs in Korea in 2017 was 1259.7 Mg, with 7 PAHs contributing 41.77 Mg. The major sector of the emissions of the 16 PAHs was <em>industrial process</em> (33.5 %). For the 7 PAHs, <em>other area source</em> was the major emission sector (38.8 %), mainly due to wildfires. In terms of regional aspects, regions with high Industrial Process activities such as ULSAN, JEONNAM, CHUNGNAM, along with GYEONGGI, a major hub for Korean Energy Transport and Storage, showed the highest emissions. The developed emission inventory was intercompared with other inventories, ensuring the appropriate application of emission factors for each emission sector. Especially, it was found that the Korean PAH emissions reported in EDGARv6.0 were 1.9–5.1 times different from those estimated in this study, depending on the pollutant. It was discovered that the emission factors in the <em>residential sector</em> in EDGARv6.0 may differ from the actual emission characteristics in Korea. The PAHs emission inventory developed in this study is anticipated to be used for the establishment and regulation of PAHs policies in Korea. Furthermore, the research results are expected to be essential reference material for refining the emission inventory of PAHs for Korea, which is used in atmospheric transport modeling.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"366 ","pages":"Article 121692"},"PeriodicalIF":3.7,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145622269","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 : 2025-11-18DOI: 10.1016/j.atmosenv.2025.121673
C.S. Neethu, B. Abish, Athira P. Ratnakaran
This study presents the first high-resolution Regional Climate Model 5 (RegCM5) analysis of the unprecedented May–June 2024 heatwave in India, evaluating the role of absorbing aerosols—black carbon (BC) and dust—in amplifying extreme heat. Heatwaves have a severe impact on health, mortality, and agriculture, with absorbing aerosols exacerbating warming. MERRA-2 Aerosol Optical Depth (AOD) anomalies show that BC peaked at +0.027 in May, weakening in June, while dust remained higher (up to +0.36), intensifying over the Indo-Gangetic Plain (IGP) and northwestern India. RegCM5 simulations, validated against India Meteorological Department (IMD) observational data, indicate that these aerosols amplified surface temperature anomalies, with BC-induced warming exceeding +4 °C in northern India during May, while dust produced stronger anomalies, surpassing +5 °C in the IGP and Rajasthan in June. BC-induced warming was vertically distributed and more pronounced under clear skies, whereas dust-induced warming was surface-concentrated and persisted longer in regions with higher dust concentrations. Both aerosols increased net shortwave radiation (SWR; >300 W m−2 for BC, ∼270 W m−2 for dust) and upward longwave radiation (ULR; >130 W m−2), inducing surface energy imbalances. This radiative forcing caused lower-tropospheric warming (up to +3 °C at 925 hPa for BC and 850 hPa for dust) and humidity deficits (−0.009 kg/kg), which stabilised the atmosphere, suppressed convection, and delayed monsoon onset. These findings highlight aerosol–radiation interactions as critical drivers of heatwave onset and persistence, emphasizing the need for their integration into regional climate models and early warning systems.
本研究首次对印度2024年5 - 6月前所未有的热浪进行了高分辨率区域气候模式5 （RegCM5）分析，评估了吸收气溶胶（黑碳（BC）和灰尘）在放大极端高温中的作用。热浪对健康、死亡率和农业产生严重影响，吸收的气溶胶加剧了气候变暖。MERRA-2气溶胶光学深度（AOD）异常显示，BC在5月达到峰值+0.027,6月减弱，而沙尘仍然较高（高达+0.36），在印度-恒河平原（IGP）和印度西北部加剧。根据印度气象部门（IMD）观测数据验证的RegCM5模拟表明，这些气溶胶放大了地表温度异常，5月份，bc引起的印度北部变暖超过+4°C，而沙尘产生了更强烈的异常，6月份在IGP和拉贾斯坦邦超过+5°C。bc引起的变暖呈垂直分布，在晴朗天气下更为明显，而沙尘引起的变暖则集中在地表，在沙尘浓度较高的地区持续时间更长。两种气溶胶都增加了净短波辐射（BC为300 W m−2，粉尘为270 W m−2）和向上的长波辐射（ULR为130 W m−2），导致地表能量不平衡。这种辐射强迫导致对流层下层变暖（BC在925 hPa时高达+3°C，尘埃在850 hPa时高达+3°C）和湿度不足（- 0.009 kg/kg），从而稳定了大气，抑制了对流，并延迟了季风的发生。这些发现强调了气溶胶-辐射相互作用是热浪发生和持续的关键驱动因素，强调了将其纳入区域气候模式和预警系统的必要性。
{"title":"Synergistic effect of absorbing aerosols on the heat wave intensification over India: A case study of the 2024 extreme event using RegCM5 model","authors":"C.S. Neethu, B. Abish, Athira P. Ratnakaran","doi":"10.1016/j.atmosenv.2025.121673","DOIUrl":"10.1016/j.atmosenv.2025.121673","url":null,"abstract":"<div><div>This study presents the first high-resolution Regional Climate Model 5 (RegCM5) analysis of the unprecedented May–June 2024 heatwave in India, evaluating the role of absorbing aerosols—black carbon (BC) and dust—in amplifying extreme heat. Heatwaves have a severe impact on health, mortality, and agriculture, with absorbing aerosols exacerbating warming. MERRA-2 Aerosol Optical Depth (AOD) anomalies show that BC peaked at +0.027 in May, weakening in June, while dust remained higher (up to +0.36), intensifying over the Indo-Gangetic Plain (IGP) and northwestern India. RegCM5 simulations, validated against India Meteorological Department (IMD) observational data, indicate that these aerosols amplified surface temperature anomalies, with BC-induced warming exceeding +4 °C in northern India during May, while dust produced stronger anomalies, surpassing +5 °C in the IGP and Rajasthan in June. BC-induced warming was vertically distributed and more pronounced under clear skies, whereas dust-induced warming was surface-concentrated and persisted longer in regions with higher dust concentrations. Both aerosols increased net shortwave radiation (SWR; >300 W m<sup>−2</sup> for BC, ∼270 W m<sup>−2</sup> for dust) and upward longwave radiation (ULR; >130 W m<sup>−2</sup>), inducing surface energy imbalances. This radiative forcing caused lower-tropospheric warming (up to +3 °C at 925 hPa for BC and 850 hPa for dust) and humidity deficits (−0.009 kg/kg), which stabilised the atmosphere, suppressed convection, and delayed monsoon onset. These findings highlight aerosol–radiation interactions as critical drivers of heatwave onset and persistence, emphasizing the need for their integration into regional climate models and early warning systems.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121673"},"PeriodicalIF":3.7,"publicationDate":"2025-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570057","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 : 2025-11-17DOI: 10.1016/j.atmosenv.2025.121690
Edward J. Stuckey , Rebecca J.L. Welbourn , Tobias W.D. Robson , Connor R. Barker , Matthew Wilkinson , James I.L. Morison , Martin D. King
Neutron reflectometry was used to examine the reaction of gas-phase hydroxyl radicals with thin surfactant films at the air–water interface. The films comprised insoluble material extracted from aerosol particulate matter collected from the atmosphere of a broadleaf woodland; sampled above and below the canopy across spring, summer, and winter. The measurements presented here act as a proxy for oxidation reactions at the air–water interface of broadleaf woodland atmospheric aqueous aerosols. The material extracted from the woodland atmosphere formed stable surfactant-like thin films at the air–water interface, with maximum thicknesses of 30 Å and neutron scattering length densities between 0.1 × 10Å −2 and 2.5 × 10Å −2. Oxidation by hydroxyl radicals reduced the amount of interfacial material, leaving an oxidation-resistant fraction of 20%–60% of the original film. The values of the surface reaction coefficients, determined by KM-SUB, for the reaction of hydroxyl radicals with woodland films were approximately 10−7 cm2 s−1. Film half-lives were estimated to be 1—2 h in typical day-time hydroxyl radical concentrations and 2 days–1 week in night-time concentrations. Thus, organic material extracted from temperate, broadleaf woodland aerosol can form thin, stable surfactant films at the air–water interface that can be partially removed by the gas-phase hydroxyl radical at a significant enough rate to warrant inclusion in atmospheric models.
{"title":"Hydroxyl (OH) radical oxidation of surfactant films formed from woodland aerosol particulate material at the air-water interface","authors":"Edward J. Stuckey , Rebecca J.L. Welbourn , Tobias W.D. Robson , Connor R. Barker , Matthew Wilkinson , James I.L. Morison , Martin D. King","doi":"10.1016/j.atmosenv.2025.121690","DOIUrl":"10.1016/j.atmosenv.2025.121690","url":null,"abstract":"<div><div>Neutron reflectometry was used to examine the reaction of gas-phase hydroxyl radicals with thin surfactant films at the air–water interface. The films comprised insoluble material extracted from aerosol particulate matter collected from the atmosphere of a broadleaf woodland; sampled above and below the canopy across spring, summer, and winter. The measurements presented here act as a proxy for oxidation reactions at the air–water interface of broadleaf woodland atmospheric aqueous aerosols. The material extracted from the woodland atmosphere formed stable surfactant-like thin films at the air–water interface, with maximum thicknesses of 30 Å and neutron scattering length densities between 0.1 × 10<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></math></span>Å <sup>−2</sup> and 2.5 × 10<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></math></span>Å <sup>−2</sup>. Oxidation by hydroxyl radicals reduced the amount of interfacial material, leaving an oxidation-resistant fraction of 20%–60% of the original film. The values of the surface reaction coefficients, determined by KM-SUB, for the reaction of hydroxyl radicals with woodland films were approximately 10<sup>−7</sup> cm<sup>2</sup> s<sup>−1</sup>. Film half-lives were estimated to be 1—2 h in typical day-time hydroxyl radical concentrations and 2 days–1 week in night-time concentrations. Thus, organic material extracted from temperate, broadleaf woodland aerosol can form thin, stable surfactant films at the air–water interface that can be partially removed by the gas-phase hydroxyl radical at a significant enough rate to warrant inclusion in atmospheric models.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121690"},"PeriodicalIF":3.7,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570008","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 : 2025-11-17DOI: 10.1016/j.atmosenv.2025.121691
Takahiro D. Ishizaka , Takafumi Matsushita , Ayato Kawashima
We evaluated the risk of Sick House Syndrome in newly constructed wooden houses by measuring the indoor concentrations of volatile organic compounds (VOCs), including α-pinene, D-limonene, and the total VOCs (TVOCs), in accordance with Japanese indoor concentration guidelines. To ensure quantitative accuracy, a field survey of 55 houses was conducted using a passive air sampling method with experimentally determined sampling rates. Health assessments were conducted using a screening-level margin-of-exposure (MOE) approach. The results revealed that apart from styrene in one house, the concentration of no compounds exceeded that of the Japanese indoor guidelines. The houses (∼80 %) exhibited α-pinene concentrations below the German bicyclic terpenes guideline (RW II). Although elevated concentrations immediately after construction pose potential short-term health risks, the rapid decline within a few months suggests minimal long-term concerns. Similarly, D-limonene concentrations in all houses were below those of the German guideline (RW II), indicating a low risk.
With the increasing prevalence of high-insulation and airtight construction, newly built wooden houses will likely experience elevated concentrations of wood-derived VOCs such as α-pinene. To mitigate these risks, it is crucial to minimize the use of adhesives and paints, conduct pre-handover air quality inspections, and ensure adequate ventilation in newly constructed houses.
{"title":"Indoor air quality and health risk assessment of α-pinene, D-limonene, and Total Volatile Organic Compounds(TVOC) in newly constructed wooden houses","authors":"Takahiro D. Ishizaka , Takafumi Matsushita , Ayato Kawashima","doi":"10.1016/j.atmosenv.2025.121691","DOIUrl":"10.1016/j.atmosenv.2025.121691","url":null,"abstract":"<div><div>We evaluated the risk of Sick House Syndrome in newly constructed wooden houses by measuring the indoor concentrations of volatile organic compounds (VOCs), including α-pinene, D-limonene, and the total VOCs (TVOCs), in accordance with Japanese indoor concentration guidelines. To ensure quantitative accuracy, a field survey of 55 houses was conducted using a passive air sampling method with experimentally determined sampling rates. Health assessments were <strong>conducted</strong> using a screening-level margin-of-exposure (MOE) approach. The results revealed that apart from styrene in one house, the concentration of no compounds exceeded that of the Japanese indoor guidelines. The houses (∼80 %) exhibited α-pinene concentrations below the German bicyclic terpenes guideline (RW II). Although elevated concentrations immediately after construction pose potential short-term health risks, the rapid decline within a few months suggests minimal long-term concerns. Similarly, D-limonene concentrations in all houses were below those of the German guideline (RW II), indicating a low risk.</div><div>With the increasing prevalence of high-insulation and airtight construction, newly built wooden houses will likely experience elevated concentrations of wood-derived VOCs such as α-pinene. To mitigate these risks, it is crucial to minimize the use of adhesives and paints, conduct pre-handover air quality inspections, and ensure adequate ventilation in newly constructed houses.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121691"},"PeriodicalIF":3.7,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570050","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 : 2025-11-17DOI: 10.1016/j.atmosenv.2025.121689
Xinpeng Ye , Jiaer Yang , Ruonan Wang , Jian Sun , Zirui Liu , Zhiwen Chen , Guohui Li , Zhenxing Shen
Despite significant progress in reducing primary pollutants in China, surface ozone pollution remains a pressing challenge. This study evaluates the effectiveness of Empirical Kinetic Modeling Approach (EKMA) curves—constructed using Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), Observation-Based Model (OBM), and Empirical Kinetic Modeling Approach for Machine Learning (MLEKMA)—in guiding ozone control strategies in Luoyang. The levels of O3 and precursors between two sampling campaigns present two main paradoxes, that reduction in source inventory do not guarantee the decrease of atmospheric NOx and VOC levels, and reduction of precursors do not always result in O3 decline. As indicated by all three models, O3 sensitivity in Luoyang was in a transition regime in both 2019 and 2021. However, only the WRF-Chem model yielded ozone concentration predictions (169.0–171.0 μg/m3) that closely matched the observed values (168.8 μg/m3), while OBM and MLEKMA significantly underestimated ozone levels—the observed concentrations were 2–3 times and 3–5 times higher than the respective model predictions. Each method presents its limitations: the WRF-Chem model lacks real-time responsiveness, while OBM and MLEKMA exhibit deficiencies in accurately predicting ozone concentrations. Therefore, integrating multiple EKMA-derived methods is recommended for practical ozone management. By leveraging the timeliness of OBM and MLEKMA alongside the predictive accuracy of WRF-Chem, a rapid and robust multi-model approach for urban ozone sensitivity assessment can be achieved, enabling governments to formulate more effective ozone control policies.
{"title":"From sensitivity regimes to policy action: Evaluating EKMA curve effectiveness with WRF-Chem, OBM, and machine learning","authors":"Xinpeng Ye , Jiaer Yang , Ruonan Wang , Jian Sun , Zirui Liu , Zhiwen Chen , Guohui Li , Zhenxing Shen","doi":"10.1016/j.atmosenv.2025.121689","DOIUrl":"10.1016/j.atmosenv.2025.121689","url":null,"abstract":"<div><div>Despite significant progress in reducing primary pollutants in China, surface ozone pollution remains a pressing challenge. This study evaluates the effectiveness of Empirical Kinetic Modeling Approach (EKMA) curves—constructed using Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), Observation-Based Model (OBM), and Empirical Kinetic Modeling Approach for Machine Learning (MLEKMA)—in guiding ozone control strategies in Luoyang. The levels of O<sub>3</sub> and precursors between two sampling campaigns present two main paradoxes, that reduction in source inventory do not guarantee the decrease of atmospheric NO<sub>x</sub> and VOC levels, and reduction of precursors do not always result in O<sub>3</sub> decline. As indicated by all three models, O<sub>3</sub> sensitivity in Luoyang was in a transition regime in both 2019 and 2021. However, only the WRF-Chem model yielded ozone concentration predictions (169.0–171.0 μg/m<sup>3</sup>) that closely matched the observed values (168.8 μg/m<sup>3</sup>), while OBM and MLEKMA significantly underestimated ozone levels—the observed concentrations were 2–3 times and 3–5 times higher than the respective model predictions. Each method presents its limitations: the WRF-Chem model lacks real-time responsiveness, while OBM and MLEKMA exhibit deficiencies in accurately predicting ozone concentrations. Therefore, integrating multiple EKMA-derived methods is recommended for practical ozone management. By leveraging the timeliness of OBM and MLEKMA alongside the predictive accuracy of WRF-Chem, a rapid and robust multi-model approach for urban ozone sensitivity assessment can be achieved, enabling governments to formulate more effective ozone control policies.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121689"},"PeriodicalIF":3.7,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570009","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 : 2025-11-15DOI: 10.1016/j.atmosenv.2025.121670
Yi Gao , Jing He , Liren Xu , Meigen Zhang
In this study the emission-driven aerosol–meteorology feedback on winter PM2.5 variations in Central and East China (CEC) from 2014 to 2020 is examined by applying the Weather Research and Forecasting (WRF) model coupled with Chemistry. Emission reductions from 2014 to 2020 led to increases in downward shortwave radiation at the surface, 2-m temperature and planetary boundary layer height, as well as decreases in 2-m relative humidity in the central part of CEC. This also led to an increase in precipitation and a decrease in the liquid water path in the southern part of CEC. The change in the PM2.5 concentration induced by aerosol‒meteorology feedback ( PM2.5) was −10 μg m−3 to −5 μg m−3 in eastern Hunan Province and −5 μg m−3 to −2 μg m−3 in other CEC regions. The average percentages of PM2.5 relative to the total change in the PM2.5 concentration due to emission reduction were 9.8 %, 5.7 %, 5.6 %, 9.2 %, and 20.3 % for CEC, the Beijing-Tianjin-Hebei (BTH), the Fenwei Plain (FWP), the Yangtze River Delta (YRD) and the Pearl River Delta (PRD), respectively. In the central part of CEC, the contribution of aerosol‒radiation interaction (ARI) dominated, with a very slight contribution from aerosol‒cloud interaction (ACI). In the southern part of CEC, both ACI and ARI contributed to PM2.5, with ACI playing a more significant role. PM2.5 exhibited distinct diurnal variations in the BTH, the FWP, and the YRD, with greater contributions during the day and smaller contributions at night, which was attributed primarily to the diurnal variation in the ARI contribution. This study emphasizes the necessity of considering aerosol–meteorology feedback when assessing the effects of emission control measures on PM2.5 concentrations.
{"title":"Assessing the impact of emission-driven aerosol-meteorology feedback on winter PM2.5 variations in central and East China from 2014 to 2020","authors":"Yi Gao , Jing He , Liren Xu , Meigen Zhang","doi":"10.1016/j.atmosenv.2025.121670","DOIUrl":"10.1016/j.atmosenv.2025.121670","url":null,"abstract":"<div><div>In this study the emission-driven aerosol–meteorology feedback on winter PM<sub>2.5</sub> variations in Central and East China (CEC) from 2014 to 2020 is examined by applying the Weather Research and Forecasting (WRF) model coupled with Chemistry. Emission reductions from 2014 to 2020 led to increases in downward shortwave radiation at the surface, 2-m temperature and planetary boundary layer height, as well as decreases in 2-m relative humidity in the central part of CEC. This also led to an increase in precipitation and a decrease in the liquid water path in the southern part of CEC. The change in the PM<sub>2.5</sub> concentration induced by aerosol‒meteorology feedback (<span><math><mrow><msub><mo>Δ</mo><mi>M</mi></msub></mrow></math></span> PM<sub>2.5</sub>) was −10 μg m<sup>−3</sup> to −5 μg m<sup>−3</sup> in eastern Hunan Province and −5 μg m<sup>−3</sup> to −2 μg m<sup>−3</sup> in other CEC regions. The average percentages of <span><math><mrow><msub><mo>Δ</mo><mi>M</mi></msub></mrow></math></span> PM<sub>2.5</sub> relative to the total change in the PM<sub>2.5</sub> concentration due to emission reduction were 9.8 %, 5.7 %, 5.6 %, 9.2 %, and 20.3 % for CEC, the Beijing-Tianjin-Hebei (BTH), the Fenwei Plain (FWP), the Yangtze River Delta (YRD) and the Pearl River Delta (PRD), respectively. In the central part of CEC, the contribution of aerosol‒radiation interaction (ARI) dominated, with a very slight contribution from aerosol‒cloud interaction (ACI). In the southern part of CEC, both ACI and ARI contributed to <span><math><mrow><msub><mo>Δ</mo><mi>M</mi></msub></mrow></math></span> PM<sub>2.5</sub>, with ACI playing a more significant role. <span><math><mrow><msub><mo>Δ</mo><mi>M</mi></msub></mrow></math></span> PM<sub>2.5</sub> exhibited distinct diurnal variations in the BTH, the FWP, and the YRD, with greater contributions during the day and smaller contributions at night, which was attributed primarily to the diurnal variation in the ARI contribution. This study emphasizes the necessity of considering aerosol–meteorology feedback when assessing the effects of emission control measures on PM<sub>2.5</sub> concentrations.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121670"},"PeriodicalIF":3.7,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570047","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 : 2025-11-15DOI: 10.1016/j.atmosenv.2025.121668
Douglas J. Gregg , Jordan Tompkins , Rebecca L. Cordell , Andrew S. Brown , Kirsty L. Smallbone , Joshua D. Vande Hey , Kevin P. Wyche , Paul S. Monks
Introduced in April 2019, the London Ultra Low Emission Zone (ULEZ) targets reductions in NOx and PM emissions to improve ambient air quality, with COVID-19 related restrictions superimposed throughout much of 2020 and 2021. However, little existing research assesses the impact of these interventions on O3 and UFP (Ultrafine particles) concentrations, or accounts for variations in meteorological or anthropogenic influences. To assess these effects, NO2, O3, PM10, PM2.5 and 51 size-channel UFP data collected between January 2015 and December 2022 were normalised using Boosted Regression Tree (BRT) models comprised of twelve predictor variables, including overall trend, time of day/year, wind speed/direction, temperature and traffic volume. The introduction of the ULEZ expedited reductions in NO2, PM10 and PM2.5 abundance, aligning with existing research, alongside reductions in nucleation mode UFP abundance and concomitant increases in O3, Aitken and accumulation mode UFP abundance. The implementation of COVID-19 restrictions expedited an increase/decrease in O3/NO2 respectively through the typical OX couple chemistry. The use of BRT models accounts for changes in the predictor variables, thereby showing that changes in atmospheric composition are not wholly a reflection of seasonality, meteorology or anthropogenic activity. The findings indicate the introduction of both ULEZ and COVID-19 restrictions precipitated a reduction in ambient concentrations of larger particulate matter (i.e. PM10, and PM2.5) and larger modes of UFPs (i.e Accumulation and Aitken), alongside increasing concentrations of nucleation mode particles. The findings reinforce the necessity of examining the impact of interventions on atmospheric composition, including changes in the abundance of secondary pollutants.
{"title":"The impacts of the Ultra Low Emission Zone (ULEZ) and COVID-19 restrictions on air quality in central London – evidence for an increase in small particles","authors":"Douglas J. Gregg , Jordan Tompkins , Rebecca L. Cordell , Andrew S. Brown , Kirsty L. Smallbone , Joshua D. Vande Hey , Kevin P. Wyche , Paul S. Monks","doi":"10.1016/j.atmosenv.2025.121668","DOIUrl":"10.1016/j.atmosenv.2025.121668","url":null,"abstract":"<div><div>Introduced in April 2019, the London Ultra Low Emission Zone (ULEZ) targets reductions in NO<sub>x</sub> and PM emissions to improve ambient air quality, with COVID-19 related restrictions superimposed throughout much of 2020 and 2021. However, little existing research assesses the impact of these interventions on O<sub>3</sub> and UFP (Ultrafine particles) concentrations, or accounts for variations in meteorological or anthropogenic influences. To assess these effects, NO<sub>2</sub>, O<sub>3</sub>, PM<sub>10</sub>, PM<sub>2.5</sub> and 51 size-channel UFP data collected between January 2015 and December 2022 were normalised using Boosted Regression Tree (BRT) models comprised of twelve predictor variables, including overall trend, time of day/year, wind speed/direction, temperature and traffic volume. The introduction of the ULEZ expedited reductions in NO<sub>2</sub>, PM<sub>10</sub> and PM<sub>2.5</sub> abundance, aligning with existing research, alongside reductions in nucleation mode UFP abundance and concomitant increases in O<sub>3</sub>, Aitken and accumulation mode UFP abundance. The implementation of COVID-19 restrictions expedited an increase/decrease in O<sub>3</sub>/NO<sub>2</sub> respectively through the typical O<sub>X</sub> couple chemistry. The use of BRT models accounts for changes in the predictor variables, thereby showing that changes in atmospheric composition are not wholly a reflection of seasonality, meteorology or anthropogenic activity. The findings indicate the introduction of both ULEZ and COVID-19 restrictions precipitated a reduction in ambient concentrations of larger particulate matter (i.e. PM<sub>10</sub>, and PM<sub>2.5</sub>) and larger modes of UFPs (i.e Accumulation and Aitken), alongside increasing concentrations of nucleation mode particles. The findings reinforce the necessity of examining the impact of interventions on atmospheric composition, including changes in the abundance of secondary pollutants.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121668"},"PeriodicalIF":3.7,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570048","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 : 2025-11-15DOI: 10.1016/j.atmosenv.2025.121688
Yohan Yang , Hyeong-Ahn Kwon , Xiaomeng Jin
Tropospheric ozone (O3), formed through photochemical reactions between volatile organic compounds (VOCs) and nitrogen oxides (NOx ≡ NO + NO2), poses detrimental risks to health and ecosystems. In South Korea, the fourth-highest maximum daily 8-h average (MDA8) O3 concentrations have increased from 53 to 89 ppbv over the past three decades, and the implementation of the carbon neutrality strategy in South Korea is expected to alter emissions of O3 precursors (NOx, VOCs). In particular, emission changes in the transportation sector can affect ozone concentrations in densely populated urban areas, thereby impacting public health outcomes. Therefore, we investigate O3 responses to transportation decarbonization using a global 3-D chemical transport model (GEOS-Chem) under mobile NOx and VOCs emission reduction scenarios. Across all scenarios involving 40 % reductions in mobile NOx emissions in South Korea, with additional VOC reductions and expanded coverage to China in some cases, MDA8 O3 concentrations increased. Furthermore, O3 production regimes in South Korea remain NOx-saturated or transitional in major cities despite NOx reductions, while suburban and remote forested regions are becoming more limited by NOx availability. NOx-only mobile emission reductions led to substantial MDA8 O3 increases (up to 4.7 ppbv) and additional six exceedance days compared to results from the control run, whereas concurrent VOCs reductions mitigated both the magnitude (2.7 ppbv) and the number of ozone exceedance days. Also, emission reductions for both NOx and VOC in South Korea and China resulted in reducing O3 exceedance days in May–July compared to results implemented only in South Korea, highlighting the importance of transboundary VOC mitigation.
{"title":"Effects of mobile emission reduction on ozone under future carbon neutrality scenarios in Korea","authors":"Yohan Yang , Hyeong-Ahn Kwon , Xiaomeng Jin","doi":"10.1016/j.atmosenv.2025.121688","DOIUrl":"10.1016/j.atmosenv.2025.121688","url":null,"abstract":"<div><div>Tropospheric ozone (O<sub>3</sub>), formed through photochemical reactions between volatile organic compounds (VOCs) and nitrogen oxides (NO<sub>x</sub> ≡ NO + NO<sub>2</sub>), poses detrimental risks to health and ecosystems. In South Korea, the fourth-highest maximum daily 8-h average (MDA8) O<sub>3</sub> concentrations have increased from 53 to 89 ppbv over the past three decades, and the implementation of the carbon neutrality strategy in South Korea is expected to alter emissions of O<sub>3</sub> precursors (NO<sub>x</sub>, VOCs). In particular, emission changes in the transportation sector can affect ozone concentrations in densely populated urban areas, thereby impacting public health outcomes. Therefore, we investigate O<sub>3</sub> responses to transportation decarbonization using a global 3-D chemical transport model (GEOS-Chem) under mobile NO<sub>x</sub> and VOCs emission reduction scenarios. Across all scenarios involving 40 % reductions in mobile NO<sub>x</sub> emissions in South Korea, with additional VOC reductions and expanded coverage to China in some cases, MDA8 O<sub>3</sub> concentrations increased. Furthermore, O<sub>3</sub> production regimes in South Korea remain NO<sub>x</sub>-saturated or transitional in major cities despite NO<sub>x</sub> reductions, while suburban and remote forested regions are becoming more limited by NO<sub>x</sub> availability. NO<sub>x</sub>-only mobile emission reductions led to substantial MDA8 O<sub>3</sub> increases (up to 4.7 ppbv) and additional six exceedance days compared to results from the control run, whereas concurrent VOCs reductions mitigated both the magnitude (2.7 ppbv) and the number of ozone exceedance days. Also, emission reductions for both NO<sub>x</sub> and VOC in South Korea and China resulted in reducing O<sub>3</sub> exceedance days in May–July compared to results implemented only in South Korea, highlighting the importance of transboundary VOC mitigation.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"365 ","pages":"Article 121688"},"PeriodicalIF":3.7,"publicationDate":"2025-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570062","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}
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