{"title":"Hybrid machine learning to enhance PM2.5 forecasting performance by the WRF-Chem model","authors":"Laddawan Noynoo , Perapong Tekasakul , Thanathip Limna , Chidchanok Choksuchat , Korakot Wichitsa-Nguan Jetwanna , Chuen-Jinn Tsai , Thi-Cuc Le , Panwadee Suwattiga , John Morris , Racha Dejchanchaiwong","doi":"10.1016/j.apr.2025.102558","DOIUrl":"10.1016/j.apr.2025.102558","url":null,"abstract":"<div><div>The weather research and forecasting with chemistry (WRF-Chem) model had been widely used in PM<sub>2.5</sub> concentration forecasting. However, uncertainties in global emission inventories, meteorological data, and simplified chemical parameterizations continue to pose challenges. We evaluated the performance of the original WRF-Chem model and three models augmented with machine learning (ML) algorithms, i.e. Long Short-Term Memory (LSTM), Extreme Gradient Boosting (XGBoost) and XGBoost-LSTM (Hybrid) approaches, to enhance forecasting accuracy. The ML models were trained and tested using dataset from WRF-Chem-simulated meteorological and pollutant data at four monitoring stations in southern Thailand during the year 2019–2020. The WRF-Chem-Hybrid model significantly improved all metrics in the original WRF-Chem results - with R<sup>2</sup> increasing from insignificant to 0.90 or more, RMSE decreasing from 7.00-15.17 μg/m<sup>3</sup> to 1.34–3.47 μg/m<sup>3</sup>, and MAE decreasing from 5.52-10.55 μg/m<sup>3</sup> to 0.79–1.49 μg/m<sup>3</sup>. The validation test during the entire 2021 performed well, with R<sup>2</sup> = 0.94–0.96, RMSE = 1.56–2.48 μg/m<sup>3</sup> and MAE = 1.01–1.56 μg/m<sup>3</sup>. The WRF-Chem-Hybrid model forecast PM<sub>2.5</sub> concentrations for 72 h in advance, with R<sup>2</sup> = 0.70–0.89, RMSE = 4.64–11.99 μg/m<sup>3</sup>, and MAE = 3.07–8.38 μg/m<sup>3</sup>. Thus, the hybrid model is suggested for forecasting PM<sub>2.5</sub> concentrations over southern Thailand and other regions up to 72 h in advance. Overall, this study demonstrated the advantages of augmenting the WRF-Chem model to form hybrid ML models to more accurately forecast PM<sub>2.5</sub> levels, their distribution and evolution over time, particularly in regions where PM<sub>2.5</sub> levels were affected by open biomass burning from both local and cross-border emissions.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102558"},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143894667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Joana Belo , Miguel Meira e Cruz , Carla Viegas , Joana Lage , Susana Marta Almeida , Sandra Cabo Verde , Célia Alves , Nuno Canha
{"title":"Sleep and indoor air quality: an exploratory polysomnographic evaluation of potential associations","authors":"Joana Belo , Miguel Meira e Cruz , Carla Viegas , Joana Lage , Susana Marta Almeida , Sandra Cabo Verde , Célia Alves , Nuno Canha","doi":"10.1016/j.apr.2025.102557","DOIUrl":"10.1016/j.apr.2025.102557","url":null,"abstract":"<div><div>This exploratory pilot study examines the potential impact of indoor environmental exposures on sleep quality, with a particular focus on a comprehensive characterization of indoor air quality (IAQ) parameters and their association with sleep architecture assessed through polysomnography. The study was conducted during the cold seasons of 2016 and 2017 with a small sample of 10 subjects from the urban area of Lisbon, Portugal. Polysomnography was performed over two consecutive weeknights, while IAQ monitoring took place over three consecutive nights using typical real-time instruments. Additionally, bioburden was assessed in each bedroom before and after the sleep period using active methods. The analysis was based on correlations between the environmental parameters and the sleep data from these 10 subjects. Parametric and non-parametric statistics were employed to examine potential associations, with a significance level set at α = 0.05. The findings showed that higher bedroom temperatures during sleep were associated with a decrease in REM sleep. Both minimum and mean heart rates (HR) increased with higher levels of CO and CO<sub>2</sub>, while post-sleep bacteria levels were linked to a decrease in maximum HR. Fungal levels in the bedrooms were associated with a reduction in NREM2, and higher formaldehyde exposure was found to increase REM sleep latency. Exposure to PM<sub>2.5</sub> negatively impacted NREM1, RDI, and snoring, while PM<sub>10</sub> levels were negatively correlated with WASO and RDI. Although these findings provide a preliminary baseline, they are based on a small sample and may not be representative, highlighting the need for future studies to confirm the effects of various IAQ parameters on sleep quality in a larger and more diverse population.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102557"},"PeriodicalIF":3.9,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143882696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Mohammad Saleh Ali-Taleshi , Alireza Riyahi Bakhtiari , Nairui Liu , Mauro Masiol , Philip K. Hopke
{"title":"Identification of PM10 episodes in Tehran, Iran: Regional versus local causes","authors":"Mohammad Saleh Ali-Taleshi , Alireza Riyahi Bakhtiari , Nairui Liu , Mauro Masiol , Philip K. Hopke","doi":"10.1016/j.apr.2025.102544","DOIUrl":"10.1016/j.apr.2025.102544","url":null,"abstract":"<div><div>Middle Eastern sand and dust storms (SDSs) can deteriorate air quality and human health of millions of inhabitants in downwind areas such as Tehran, Iran. Limited information is available about severity, frequency, magnitude, and duration of PM<sub>10</sub> episodes in Tehran. To identify PM<sub>10</sub> episodes between 2015 and 2021, the Seasonal-Trend decomposition procedure based on Loess (STL) method was applied to measured PM<sub>10</sub> concentrations at 15 sites across Tehran. The PM<sub>10</sub> episodes were separated into 3 duration categories (PE1, PE2, and PE3). The PM<sub>10</sub> concentrations and related meteorological characteristics of the episodes were analyzed to assess the differences. All sites had higher PM<sub>10</sub> concentrations compared to AQG levels for daily (24-h) PM<sub>10</sub> (45 μg m<sup>−3</sup>). PM<sub>10</sub> episode frequency, magnitude, and duration were 2.60/year, 35.0 percent, and 1 day/episode over the 7-years study period, respectively. The overall frequency of PM<sub>10</sub> PE1, PE2, and PE3 events were 205, 54, and 14, respectively. Events dissipated under strong westerly winds. PM<sub>10</sub> accumulation occurred periods of weakening of the westerly winds to stagnant conditions. Site-specific bivariate polar plots (BBPs) also supported this finding. The increase of regional dust during high wind speeds on dusty days led to lower PM<sub>2.5</sub>/PM<sub>10</sub> ratios at most sites. Back trajectory analyses of PM<sub>10</sub> concentrations showed that the transboundary transport from westerly directions produced the high PM<sub>10</sub> concentrations. Understanding the PM<sub>10</sub> pollution episode characteristics could permit planning of practical anthropogenic emissions reductions and support the joint air pollution control strategies for regional air pollution.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102544"},"PeriodicalIF":3.9,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Dimitris Stratoulias , Beomgeun Jang , Narissara Nuthammachot
{"title":"Evaluation of urban PM2.5 concentrations over 73 major cities and their association with satellite Aerosol Optical Depth: A global analysis of ambient air pollution","authors":"Dimitris Stratoulias , Beomgeun Jang , Narissara Nuthammachot","doi":"10.1016/j.apr.2025.102556","DOIUrl":"10.1016/j.apr.2025.102556","url":null,"abstract":"<div><div>Air pollution is a notable environmental health risk factor in modern society, affecting 99 % of the population. In the current study, we investigate the global fine Particulate Matter (PM2.5) urban footprint based on PM2.5 surface measurements from 76 AirNow stations worldwide from January 2019 until March 2024 and investigate the association with satellite-based Aerosol Optical Depth (AOD). All 76 stations in all years, with no exception, exceed the World Health Organization (WHO) annual average air quality guideline level (i.e., 5 μg/m<sup>3</sup>), and 29 stations exceed the WHO annual average interim target 1 (i.e., 35 μg/m<sup>3</sup>). The global map of the mean PM2.5 concentrations indicate a hotspot in South Asia where these concentrations sustain considerably high levels. Disaggregation by World Bank country income level groups reveals income inequality with a gap between the lower-middle (median 42.1 μg/m<sup>3</sup>) and the upper-middle (22.5 μg/m<sup>3</sup>) income countries. Site-specific correlations on PM2.5-AOD pairs from AirNow and the Moderate Resolution Imaging Spectroradiometer (MODIS), respectively, for statistically significant observations show a large variation between stations, with R ranging between −0.60 and 0.79. In a case study over Vientiane, Laos, the Geostationary Environment Monitoring Spectrometer (GEMS) and MODIS AOD satellite products indicate a considerably higher number of GEMS observations available due to intra-day acquisition capability. A closer look at the GEMS AOD-PM2.5 hourly pairs show a clear diurnal pattern. The results of this large-scale experiment showcase the robustness and applicability of the synergistic use of the global AirNow surface monitoring system and satellite products.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102556"},"PeriodicalIF":3.9,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143943304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Prince Vijay , Vinayak Sahota , Rajdeep Singh , Shreya Dubey , Sonali Borse , Harish C. Phuleria
{"title":"Indoor air quality assessment of particulate matter levels in urban homes in India","authors":"Prince Vijay , Vinayak Sahota , Rajdeep Singh , Shreya Dubey , Sonali Borse , Harish C. Phuleria","doi":"10.1016/j.apr.2025.102553","DOIUrl":"10.1016/j.apr.2025.102553","url":null,"abstract":"<div><div>Indoor air pollution with respect to particulate matter (PM) levels have not been investigated as intensively as those of outdoor pollution. In this pilot study, we address this gap by assessing indoor PM levels, the factors that influence it, and their spatio-temporal variations across four Indian cities: Delhi, Mumbai, Bangalore, and Mysore. We used low-cost monitors (LCMs) to measure residents’ PM exposure for ∼24–48 h. Average concentrations of PM<sub>1</sub> were 60.0 ± 22.7 in Delhi, 34.0 ± 12.8 in Mumbai, 26.3 ± 3.9 in Bangalore, and 24.2 ± 8.0 μg m<sup>−3</sup> in Mysore. PM<sub>2.5</sub> (PM<sub>10</sub>) levels were 80.6 ± 26.5 (88.5 ± 24.4), 48.7 ± 17.3 (57.0 ± 17.6), 37.5 ± 5.9 (44.9 ± 8.4), and 33.2 ± 11.7 (38.7 ± 15.2) μg m<sup>−3</sup>, respectively (p < 0.05). The average daily indoor PM<sub>1</sub> (PM<sub>2.5</sub>, PM<sub>10</sub>) during cooking was 30 % (32 %, 35 %) higher than that during non-cooking hours, and homes with longer cooking periods (≥2 h) showed ∼40 % higher PM levels. Indoor PM was strongly correlated to outdoor PM levels (R<sup>2</sup> > 0.70). Indoor sources contributed only ∼10 % to the overall daily indoor PM levels, and the combined contribution of indoor and local outdoor sources to indoor PM was ∼33 %. Indoor PM employing the real-time LCS showed higher variability within homes than between homes, indicating that longer-term measurements should be conducted to accurately capture the variability. The study highlights that acute exposures are closely associated with short-term, temporarily generated indoor pollutants, while outdoor sources contribute significantly to chronic exposure to indoor PM.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102553"},"PeriodicalIF":3.9,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Chao Peng , Chongzhi Zhai , Yang Chen , Mi Tian , Ying Xiang , Tianyu Zhai , Weikai Fang , Xin Long , Xiaocheng Wang , Mulan Chen , Yunqing Cao , Min Du , Zhenliang Li
{"title":"Inter-model comparison of the DRI-2001 and DRI-2015 for carbonaceous aerosol analysis in PM2.5: Method development and application in Chongqing","authors":"Chao Peng , Chongzhi Zhai , Yang Chen , Mi Tian , Ying Xiang , Tianyu Zhai , Weikai Fang , Xin Long , Xiaocheng Wang , Mulan Chen , Yunqing Cao , Min Du , Zhenliang Li","doi":"10.1016/j.apr.2025.102555","DOIUrl":"10.1016/j.apr.2025.102555","url":null,"abstract":"<div><div>Thermal-optical method is widely used to determine organic carbon (OC) and elemental carbon (EC) in PM<sub>2.5</sub> collected on filters. DRI-2001 and DRI-2015 analyzers have both been extensively employed with the IMPROVE_A protocol in the recent decades. However, differences in detectors and lasers between the two models can affect the measurement results. In this study, a novel using multiple linear regression was developed to equalize carbon fraction results between DRI-2001 and DRI-2015. After adjustment, high inter-model consistency was observed, with a mean bias within 5 % for total carbon (TC) and OC, and ∼10 % for EC. Larger inter-model differences (5.2 %–121.5 %) were found in OC1-OC4 and EC1-EC3. Fractions with high mass loading, particularly those linked to biomass burning (BB) and coal combustion (CC) (e.g., OC1, OC2 and OC4), exhibited better agreement after adjustment, with smaller mean bias within ∼15 % and higher R<sup>2</sup> values above 0.93 (<em>p</em> < 0.001). During winter in Wanzhou, the adjusted carbon fractions exhibited significantly improved inter-model agreement (<em>p</em> < 0.001). BB and CC were identified as the primary sources of carbonaceous aerosol, while secondary organic carbon (SOC) also contributed to elevated TC concentrations during pollution periods. Similar to DRI-2001 results, DRI-2015 measurements during winter indicated that CC and BB contributed 47.5 %, diesel exhaust 18.0 %, gasoline exhaust 21.6 %, and secondary formation 12.9 % to TC. These findings enhance our understanding of uncertainties and differences between models, leading to more accurate characterization of carbonaceous aerosol.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102555"},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Panita Khwanmueng , Racha Dejchanchaiwong , Perapong Tekasakul , Nobchonnee Nim , Aulia Ullah , Kunaifi Kunaifi , John Morris
{"title":"Concurrent study of long-range transport of fine and ultrafine particles from peatland fires in lower Southeast Asia","authors":"Panita Khwanmueng , Racha Dejchanchaiwong , Perapong Tekasakul , Nobchonnee Nim , Aulia Ullah , Kunaifi Kunaifi , John Morris","doi":"10.1016/j.apr.2025.102554","DOIUrl":"10.1016/j.apr.2025.102554","url":null,"abstract":"<div><div>The physical and chemical characteristics of atmospheric fine (PM<sub>1</sub> and PM<sub>2.5</sub>) and ultrafine particles (PM<sub>0.1</sub>), during peatland fires in Indonesia and transported over a long distance to southern Thailand, were investigated to add more insight into the impact in lower Southeast Asia region. The background PM concentrations in Pekanbaru, Indonesia were approximately 1.5–3 times as high as those in Hat Yai, southern Thailand. The PM and PM-bound PAH mass concentrations in Hat Yai during the haze event were significantly increased over the background. The prominent PAH profiles during the haze event in Hat Yai showed a similar pattern to those in Pekanbaru. This suggested that the aerosol from the peatland fire in Indonesia was transported over long distances to southern Thailand. Moreover, the chemical mass balance model indicated that the most dominant source of PM<sub>0.1</sub> at both sites during normal event was vehicle fuel combustion. This is contrast with PM<sub>1</sub> and PM<sub>2.5</sub> where the biomass burning was the major source. On the other hand, during the haze event, the main source of PM<sub>0.1</sub> at Pekanbaru was clearly peatland fires, accounting for 51–65 %, whereas at Hat Yai, the most dominant source of PM<sub>0.1</sub> was vehicle fuel combustion accounting for 66 % even though the contribution from peatland fires was noticeable (17 %). This is in contrast with PM<sub>1</sub> and PM<sub>2.5</sub>, where peatland fires were the main source, contributing 38–50 %.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102554"},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143874139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
{"title":"Quantifying the contribution of periodicity and national holidays to air pollution levels in the United Kingdom using a decomposable time series model","authors":"Christopher E. Rushton, James E. Tate","doi":"10.1016/j.apr.2025.102533","DOIUrl":"10.1016/j.apr.2025.102533","url":null,"abstract":"<div><div>This paper quantifies the impact of periodicity and national holidays on air pollution levels in the United Kingdom using a decomposable time series forecasting model. The analysis focuses on nitrogen dioxide (<span><math><mrow><mi>N</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>) concentrations, with data sourced from the Automatic Urban and Rural Network and Air Quality England networks between January 2017 and December 2023. The Prophet model developed by Meta is used to identify, quantify, and appropriately remove the temporal periodicities in air pollution concentration, demonstrating how annual holidays such as Christmas, and one-off events, such as the state funeral of Elizabeth II and the London Marathon, influence local air pollution in isolation. The findings provide empirical evidence supporting widely held assumptions around national holidays and show some localised reductions in <span><math><mrow><mi>N</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span> concentrations during major events, with contextual variation also observed. For example, the state funeral of Elizabeth II shows a reduction in <span><math><mrow><mn>21</mn><mo>.</mo><mn>15</mn><mspace></mspace><mi>μ</mi><mi>g</mi><msup><mrow><mi>m</mi></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math></span> compared to a median reduction of <span><math><mrow><mo>−</mo><mn>2</mn><mo>.</mo><mn>43</mn><mspace></mspace><mi>μ</mi><mi>g</mi><msup><mrow><mi>m</mi></mrow><mrow><mo>−</mo><mn>3</mn></mrow></msup></mrow></math></span> outside of London for urban traffic sites. This paper emphasises the need for localised air pollution mitigation policies and demonstrates the utility of large, complete, and publicly available datasets coupled with modern forecasting tools in environmental research.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102533"},"PeriodicalIF":3.9,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143870615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Jiarong Li , Shuang Zhang , Wanqi Wu , Xuli Jing , Chao Zhu , Jinhe Wang
{"title":"Characteristics and deposition capacities of the chemical components in frost in Jinan, China","authors":"Jiarong Li , Shuang Zhang , Wanqi Wu , Xuli Jing , Chao Zhu , Jinhe Wang","doi":"10.1016/j.apr.2025.102551","DOIUrl":"10.1016/j.apr.2025.102551","url":null,"abstract":"<div><div>Frost usually occurs at night when the temperature falls below the freezing point and the air is saturated with water vapor. In this study, 57 frost samples were collected over two winters (2020 and 2021) in Jinan, a central city located in the North China Plain. The concentrations of water-soluble ions (WSIs), polycyclic aromatic hydrocarbons (PAHs) and nitrated phenols (NPs) in the frost samples were measured using ion chromatography, gas chromatography–mass spectrometry, and ultra-high-performance liquid chromatography–mass spectrometry, respectively. The characteristics and inter relationships were summarized comprehensively. In addition, the deposition effect of frost was investigated. Results showed that each frost process resulted the deposition of 5.6 mg m<sup>−2</sup> WSIs, 0.22 μg m<sup>−2</sup> PAHs and 4.1 μg m<sup>−2</sup> NPs. The monthly deposition fluxes of the WSIs and PAHs through frost were two orders of magnitude lower than those through rain and dry deposition. For the first time, this study calculated the deposition capacity (DC), which indicates how readily a chemical component is eliminated during the frost process. The DC values obtained by chemical group ranked as follows: NPs (362.1 ± 120.3) > WSIs (107.5 ± 61.9) > PAHs (4.8 ± 4.0), indicating that NPs were more easily removed through frost deposition, whereas PAHs were the least likely to be deposited. Among individual components, Ca<sup>2+</sup> and 5-nitrosalicylic acid exhibited the highest DC values (>600.0), indicating that they participated actively in the frost pross. Furthermore, NP components containing more carboxyl groups and fewer hydroxyl groups were found to have higher DC values.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102551"},"PeriodicalIF":3.9,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Lianhuan Fan , Shumao Gu , Huaizhong Yan , Junxiao Zhang , Miao Zhang , Xiaofeng Wei , Guiqin Zhang
{"title":"A comprehensive analysis of O3 variation and source contributions of VOCs-oriented to O3 pollution episodes over Jinan city, China","authors":"Lianhuan Fan , Shumao Gu , Huaizhong Yan , Junxiao Zhang , Miao Zhang , Xiaofeng Wei , Guiqin Zhang","doi":"10.1016/j.apr.2025.102552","DOIUrl":"10.1016/j.apr.2025.102552","url":null,"abstract":"<div><div>Although severe ozone (O<sub>3</sub>) pollution has been frequently observed during summer over Jinan city in northern China, which underscores the necessity of mitigating O<sub>3</sub> pollution, the key formation processes and prominent sources of O<sub>3</sub> pollution episode remain poorly characterized. In this study, the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) modeling system was employed to investigate the formation mechanism of O<sub>3</sub> pollution during summer in Jinan. In addition, the Integrated Source Apportionment Method (ISAM) was subsequently applied to determine the major VOCs contributors to elevated O<sub>3</sub> levels. During O<sub>3</sub> pollution episodes, increased O<sub>3</sub> concentrations generated by gas-chemistry at high altitudes were transported to the ground through vertical transport, exacerbating surface-level O<sub>3</sub> pollution caused by photochemical reactions during daytime. The declined height of the planetary boundary layer (PBLH) and vertical mixing, which form O<sub>3</sub>-rich residual layers, were identified as the key drivers of the O<sub>3</sub> accumulation and enhancement near the surface during nighttime. Furthermore, ISAM results indicate that terminal olefin carbon bonds (OLE), internal olefin carbon bonds (IOLE), and ethene (ETH) playing essential roles in O<sub>3</sub> formation, collectively contributing up to 60 %. This implicates great importance of vehicle exhaust and the use of liquefied petroleum gas (LPG) and natural gas (NG) over Jinan city. Our findings offer possible explanations for O<sub>3</sub> pollution episode and provide a quantitative understanding of O<sub>3</sub> source apportionment, guiding the control strategy of VOCs-oriented on O<sub>3</sub> mitigation.</div></div>","PeriodicalId":8604,"journal":{"name":"Atmospheric Pollution Research","volume":"16 8","pages":"Article 102552"},"PeriodicalIF":3.9,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}