Pub Date : 2026-01-27DOI: 10.1016/j.atmosenv.2026.121831
Xavier Querol , Andrés Alastuey , Jorge Pey , Pedro Salvador , Adolfo González-Romero , Noemí Pérez
There is a body of evidence on the risk to human health posed by the exposure to desert dust. However, results from epidemiological studies from different regions are inconsistent. Among possible causes of inconsistency is the scarcity of daily desert dust contributions to PM10 and PM2.5 levels recorded in populated areas in order to conduct rigorous epidemiological studies, but also the lack of robust and harmonized methodologies to deliver airborne desert-dust concentrations. This study evaluated the performance of the main statistical methods currently used by European countries to estimate the net load of desert dust on PM10 and PM2.5 levels during the occurrence of desert dust outbreaks. To this end, long-term data series (2010–2023) on PM10 and PM2.5 levels and composition obtained in a regional background (Montseny) and an urban background (Barcelona) monitoring site, in Northeast Spain, were used. The results identify the most appropriate method for determining the regional daily PM10 background concentration, excluding dust-days. This involves applying a moving 50th percentile with a 30-day time window to data from nearby regional background environments. Such PM10 background is essential for calculating the daily net dust contribution (PM10 net-dust). However, applying this procedure to data from urban or industrial environments causes an overestimation of PM10 net-dust values, which intensifies with higher local PM10 levels. On the other hand, in the case of low PM10net-dust values(<3 μg m−3) the relative errors are so high that it is not advisable to use these estimates of natural PM contributions to assess compliance with air quality standards. For PM2.5, however, the mineral dust content is much lower than for PM10. Consequently, applying the same methodology results in significantly greater relative errors in the PM2.5 net-dust estimates. In this case, it is also advisable to use PM2.5 data series obtained in regional background environments. However, if nearby regional background data is not available, the method can be applied directly to the evaluated urban or industrial datasets, but excluding traffic and industrial hotspots for the calculation of the PMnet-dust. In conclusion, accurately quantifying PMnet-dust is a complex issue, and it is necessary to continue improving current methods and developing new methods that allow for the most accurate estimation possible of daily desert dust contributions, especially for the low concentration ranges and for finer PM size fractions. The methodologies reported here are applicable to all regions affected by desert dust.
{"title":"Evaluation of the performance of receptor statistical methods for quantifying desert dust contributions to ambient particulate for health studies and policy","authors":"Xavier Querol , Andrés Alastuey , Jorge Pey , Pedro Salvador , Adolfo González-Romero , Noemí Pérez","doi":"10.1016/j.atmosenv.2026.121831","DOIUrl":"10.1016/j.atmosenv.2026.121831","url":null,"abstract":"<div><div>There is a body of evidence on the risk to human health posed by the exposure to desert dust. However, results from epidemiological studies from different regions are inconsistent. Among possible causes of inconsistency is the scarcity of daily desert dust contributions to PM<sub>10</sub> and PM<sub>2.5</sub> levels recorded in populated areas in order to conduct rigorous epidemiological studies, but also the lack of robust and harmonized methodologies to deliver airborne desert-dust concentrations. This study evaluated the performance of the main statistical methods currently used by European countries to estimate the net load of desert dust on PM<sub>10</sub> and PM<sub>2.5</sub> levels during the occurrence of desert dust outbreaks. To this end, long-term data series (2010–2023) on PM<sub>10</sub> and PM<sub>2.5</sub> levels and composition obtained in a regional background (Montseny) and an urban background (Barcelona) monitoring site, in Northeast Spain, were used. The results identify the most appropriate method for determining the regional daily PM<sub>10</sub> background concentration, excluding dust-days. This involves applying a moving 50th percentile with a 30-day time window to data from nearby regional background environments. Such PM<sub>10 background</sub> is essential for calculating the daily net dust contribution (PM<sub>10 net-dust</sub>). However, applying this procedure to data from urban or industrial environments causes an overestimation of PM<sub>10 net-dust</sub> values, which intensifies with higher local PM<sub>10</sub> levels. On the other hand, in the case of low PM<sub>10</sub> <sub>net-dust</sub> values(<3 μg m<sup>−3</sup>) the relative errors are so high that it is not advisable to use these estimates of natural PM contributions to assess compliance with air quality standards. For PM<sub>2.5</sub>, however, the mineral dust content is much lower than for PM<sub>10</sub>. Consequently, applying the same methodology results in significantly greater relative errors in the PM<sub>2.5 net-dust</sub> estimates. In this case, it is also advisable to use PM<sub>2.5</sub> data series obtained in regional background environments. However, if nearby regional background data is not available, the method can be applied directly to the evaluated urban or industrial datasets, but excluding traffic and industrial hotspots for the calculation of the PM<sub>net-dust</sub>. In conclusion, accurately quantifying PM<sub>net-dust</sub> is a complex issue, and it is necessary to continue improving current methods and developing new methods that allow for the most accurate estimation possible of daily desert dust contributions, especially for the low concentration ranges and for finer PM size fractions. The methodologies reported here are applicable to all regions affected by desert dust.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"370 ","pages":"Article 121831"},"PeriodicalIF":3.7,"publicationDate":"2026-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075941","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 : 2026-01-24DOI: 10.1016/j.atmosenv.2026.121830
C. Frederiksen , D. Farmer , J.D. Whyatt , D. Booker , A. Sweetman , R. Fitton
Domestic cooking is a key contributor to poor indoor air quality (IAQ) and one of the most significant indoor sources of particulate matter, including ultrafine particles (UFPs). Since cooking forms an essential part of domestic life, cost-effective active abatement strategies are necessary to improve IAQ. Increasing the ventilation rate by natural or mechanical means will reduce cooking related UFP concentrations but can lead to domestic heat loss: this represents an IAQ and energy efficiency dichotomy. In this study a specialist test facility is used to explore this dichotomy during short-duration cooking activities replicated under different ventilation scenarios, both related to natural and mechanical ventilation in the kitchen, and the relationship between ventilation and airflow around the home more generally. We relate our results to the recently introduced World Health Organization (WHO) good practice statement on UFPs to determine good IAQ. Energy penalties associated with heat loss are calculated to determine which combinations of behavioural and technological interventions can best balance the competing demands of good IAQ and energy efficiency. It was seen that IAQ benefits were achieved at little detriment to energy efficiency. For natural ventilation, behavioural interventions such as opening windows for 20 min yielded significant IAQ benefits, reducing UFPs from peak values by 86 %. Similarly, 20 min of mechanical extract ventilation operation yielded IAQ benefits, reducing UFPs from peak values by 94 %. However, in all ventilation scenarios UFPs remained above the WHO good practice high threshold for ∼1 h. All mechanical extract ventilation scenarios resulted in lower energy penalties than for natural ventilation. Our experiments also show that airflow within the house is important to consider when looking at the IAQ and energy efficiency dichotomy. Whilst results are primarily concerned with managing IAQ and energy efficiency under domestic cooking scenarios, there are wider implications for balancing IAQ and energy efficiency, which have increasing importance in light of management of the COVID-19 and energy crises and future policy, such as the Future Homes Standard.
{"title":"Quantifying the trade-offs between indoor air quality and energy efficiency in a specialised test facility","authors":"C. Frederiksen , D. Farmer , J.D. Whyatt , D. Booker , A. Sweetman , R. Fitton","doi":"10.1016/j.atmosenv.2026.121830","DOIUrl":"10.1016/j.atmosenv.2026.121830","url":null,"abstract":"<div><div>Domestic cooking is a key contributor to poor indoor air quality (IAQ) and one of the most significant indoor sources of particulate matter, including ultrafine particles (UFPs). Since cooking forms an essential part of domestic life, cost-effective active abatement strategies are necessary to improve IAQ. Increasing the ventilation rate by natural or mechanical means will reduce cooking related UFP concentrations but can lead to domestic heat loss: this represents an IAQ and energy efficiency dichotomy. In this study a specialist test facility is used to explore this dichotomy during short-duration cooking activities replicated under different ventilation scenarios, both related to natural and mechanical ventilation in the kitchen, and the relationship between ventilation and airflow around the home more generally. We relate our results to the recently introduced World Health Organization (WHO) good practice statement on UFPs to determine good IAQ. Energy penalties associated with heat loss are calculated to determine which combinations of behavioural and technological interventions can best balance the competing demands of good IAQ and energy efficiency. It was seen that IAQ benefits were achieved at little detriment to energy efficiency. For natural ventilation, behavioural interventions such as opening windows for 20 min yielded significant IAQ benefits, reducing UFPs from peak values by 86 %. Similarly, 20 min of mechanical extract ventilation operation yielded IAQ benefits, reducing UFPs from peak values by 94 %. However, in all ventilation scenarios UFPs remained above the WHO good practice high threshold for ∼1 h. All mechanical extract ventilation scenarios resulted in lower energy penalties than for natural ventilation. Our experiments also show that airflow within the house is important to consider when looking at the IAQ and energy efficiency dichotomy. Whilst results are primarily concerned with managing IAQ and energy efficiency under domestic cooking scenarios, there are wider implications for balancing IAQ and energy efficiency, which have increasing importance in light of management of the COVID-19 and energy crises and future policy, such as the Future Homes Standard.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"370 ","pages":"Article 121830"},"PeriodicalIF":3.7,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075944","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 : 2026-01-24DOI: 10.1016/j.atmosenv.2026.121827
Shixin Mai , Kunpeng Chen , Hengjia Ou , Li Chen , Dexian Chen , Shengzhen Zhou
Methoxyphenols, as emitted abundantly from biomass burning, are important precursors of brown carbon (BrC) in the atmosphere. However, the effects of environmental factors on their gas-phase oxidation by nitrate radicals (NO3), the dominant nighttime oxidant, remain poorly understood. In this study, the reaction of vanillin, a proxy for methoxyphenols, with NO3 was investigated in a smog chamber under six environmental conditions, varied by pre-existing seed particles levels and relative humidity (RH). The NO3-driven oxidation under different environmental conditions consistently produced secondary BrC, with nitrogen-containing species identified as the dominant reaction products. Both seed level and RH were found to be critical environmental controls; higher seed concentrations promoted secondary organic aerosol (SOA) formation and increased mass absorption coefficient (MAC) under dry conditions but suppressed them under humid conditions. Furthermore, variations in seed concentration and RH guided the reaction pathways to distinct product distributions. Our findings also revealed that humid conditions may enhance the concentration of low-molecular-weight species regardless of seed levels. Overall, this work reveals how environmental conditions modulate secondary BrC formation from methoxyphenols oxidation with NO3, providing critical constraints for atmospheric models of aerosol optical properties.
{"title":"Effects of seed particles and relative humidity on brown carbon formation from NO3-driven oxidation of vanillin","authors":"Shixin Mai , Kunpeng Chen , Hengjia Ou , Li Chen , Dexian Chen , Shengzhen Zhou","doi":"10.1016/j.atmosenv.2026.121827","DOIUrl":"10.1016/j.atmosenv.2026.121827","url":null,"abstract":"<div><div>Methoxyphenols, as emitted abundantly from biomass burning, are important precursors of brown carbon (BrC) in the atmosphere. However, the effects of environmental factors on their gas-phase oxidation by nitrate radicals (NO<sub>3</sub>), the dominant nighttime oxidant, remain poorly understood. In this study, the reaction of vanillin, a proxy for methoxyphenols, with NO<sub>3</sub> was investigated in a smog chamber under six environmental conditions, varied by pre-existing seed particles levels and relative humidity (RH). The NO<sub>3</sub>-driven oxidation under different environmental conditions consistently produced secondary BrC, with nitrogen-containing species identified as the dominant reaction products. Both seed level and RH were found to be critical environmental controls; higher seed concentrations promoted secondary organic aerosol (SOA) formation and increased mass absorption coefficient (MAC) under dry conditions but suppressed them under humid conditions. Furthermore, variations in seed concentration and RH guided the reaction pathways to distinct product distributions. Our findings also revealed that humid conditions may enhance the concentration of low-molecular-weight species regardless of seed levels. Overall, this work reveals how environmental conditions modulate secondary BrC formation from methoxyphenols oxidation with NO<sub>3</sub>, providing critical constraints for atmospheric models of aerosol optical properties.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"370 ","pages":"Article 121827"},"PeriodicalIF":3.7,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075940","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 : 2026-01-23DOI: 10.1016/j.atmosenv.2026.121812
Luyao Chen , Renzhi Hu , Longsheng Wei , Chuan Lin , Pinhua Xie
Nocturnal atmospheric oxidizing capacity plays a pivotal role in nitrogen oxide (NOx) transformation, ozone (O3) lifetime regulation, and particulate matter pollution control, with the nitrate radical (NO3) serving as the central species in nighttime oxidation processes. The spatiotemporal characteristics of nocturnal NO3 production rate (PNO3) and its influencing factors are investigated in the Yangtze River Delta (YRD) region based on ground-level observations and meteorological data from 2017 to 2024. The results demonstrated that the YRD region exhibited an overall declining trend in concentrations of NO2, O3, Ox and PNO3 under policy-driven emission reductions. However, NO2 and PNO3 concentrations experienced a temporary rebound during the 2020 pandemic period, while O3 levels showed a significant increase in 2022, revealing the nonlinear response of nocturnal oxidizing capacity to both policy interventions and pandemic restrictions. Based on the measured data of Hefei in summer from 2020 to 2022, the research identified that local high-intensity emissions can still form night-time oxidation hotspots.
{"title":"Policy-driven emission reduction and the COVID-19 lockdown paradox: Long-term decline, short-term rebound, and regional heterogeneity of nocturnal atmospheric oxidation in the Yangtze River Delta","authors":"Luyao Chen , Renzhi Hu , Longsheng Wei , Chuan Lin , Pinhua Xie","doi":"10.1016/j.atmosenv.2026.121812","DOIUrl":"10.1016/j.atmosenv.2026.121812","url":null,"abstract":"<div><div>Nocturnal atmospheric oxidizing capacity plays a pivotal role in nitrogen oxide (NOx) transformation, ozone (O<sub>3</sub>) lifetime regulation, and particulate matter pollution control, with the nitrate radical (NO<sub>3</sub>) serving as the central species in nighttime oxidation processes. The spatiotemporal characteristics of nocturnal NO<sub>3</sub> production rate (PNO<sub>3</sub>) and its influencing factors are investigated in the Yangtze River Delta (YRD) region based on ground-level observations and meteorological data from 2017 to 2024. The results demonstrated that the YRD region exhibited an overall declining trend in concentrations of NO<sub>2</sub>, O<sub>3</sub>, Ox and PNO<sub>3</sub> under policy-driven emission reductions. However, NO<sub>2</sub> and PNO<sub>3</sub> concentrations experienced a temporary rebound during the 2020 pandemic period, while O<sub>3</sub> levels showed a significant increase in 2022, revealing the nonlinear response of nocturnal oxidizing capacity to both policy interventions and pandemic restrictions. Based on the measured data of Hefei in summer from 2020 to 2022, the research identified that local high-intensity emissions can still form night-time oxidation hotspots.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"370 ","pages":"Article 121812"},"PeriodicalIF":3.7,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075939","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 : 2026-01-23DOI: 10.1016/j.atmosenv.2026.121829
Shuqi Guo , Chengyi Fan , Nan Ma , Chunsheng Zhao
Droplet evaporation is a fundamental process with broad implications for cloud microphysics and atmospheric chemistry. Solutes introduce non-ideal behaviour that alters the droplet's microphysical properties and reconfigures its evaporation dynamics, yet their influence remains insufficiently quantified. Using an optical tweezers system, we investigated the evaporation of droplets containing non-volatile solutes. The results reveal distinct stagewise variation in evaporation rate, driven by a gradual transition in the dominant microphysical mechanism from vapour diffusion across the gas–liquid interface to bulk-phase diffusion within the droplet. Once bulk-phase diffusion becomes dominant, the evaporation rate decreases significantly and the overall evaporation time increases, indicating that classical evaporation theory underestimates droplet lifetime by neglecting internal mass transport. A new radius–time relationship that better aligns with experimental observations is proposed and highlights the decisive role of solutes in both the initial conditions and the dynamic evolution of droplet evaporation. These findings advance our understanding of the microphysical evolution of droplet evaporation, providing a physical basis for improving the parameterisation of aerosol–cloud interactions and droplet lifetime in atmospheric models.
{"title":"A new radius–time relationship for droplet evaporation revealing vapour-to-bulk diffusion transition via optical tweezers","authors":"Shuqi Guo , Chengyi Fan , Nan Ma , Chunsheng Zhao","doi":"10.1016/j.atmosenv.2026.121829","DOIUrl":"10.1016/j.atmosenv.2026.121829","url":null,"abstract":"<div><div>Droplet evaporation is a fundamental process with broad implications for cloud microphysics and atmospheric chemistry. Solutes introduce non-ideal behaviour that alters the droplet's microphysical properties and reconfigures its evaporation dynamics, yet their influence remains insufficiently quantified. Using an optical tweezers system, we investigated the evaporation of droplets containing non-volatile solutes. The results reveal distinct stagewise variation in evaporation rate, driven by a gradual transition in the dominant microphysical mechanism from vapour diffusion across the gas–liquid interface to bulk-phase diffusion within the droplet. Once bulk-phase diffusion becomes dominant, the evaporation rate decreases significantly and the overall evaporation time increases, indicating that classical evaporation theory underestimates droplet lifetime by neglecting internal mass transport. A new radius–time relationship that better aligns with experimental observations is proposed and highlights the decisive role of solutes in both the initial conditions and the dynamic evolution of droplet evaporation. These findings advance our understanding of the microphysical evolution of droplet evaporation, providing a physical basis for improving the parameterisation of aerosol–cloud interactions and droplet lifetime in atmospheric models.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"370 ","pages":"Article 121829"},"PeriodicalIF":3.7,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075938","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 : 2026-01-22DOI: 10.1016/j.atmosenv.2026.121826
Rui Sun , Guiying You , Danlin Song , Miao Feng , Hefan Liu , Shaodong Xie
<div><div>To investigate the concentration, sources of volatile organic compounds (VOCs), and their impact on the formation of secondary particulate matter under different PM<sub>2.5</sub> concentration levels in ambient air, a one-month online observation of ambient VOCs and PM<sub>2.5</sub> concentrations was conducted in Chengdu, China during winter. The results showed that the concentrations of most VOC species increased significantly with the rising PM<sub>2.5</sub> concentration. The Concentration and proportions of alkenes/alkynes, halocarbons, aromatics, and oxygenated VOCs (OVOCs) all increased as PM<sub>2.5</sub> concentrations rose, with alkenes and alkynes showing a more prominent increase. However, the proportion of alkanes decreased with increasing PM<sub>2.5</sub> concentration, yet they still accounted for over 40 % of total VOCs concentrations. During moderately polluted period (PM<sub>2.5</sub>>115 μg/m<sup>3</sup>), the concentrations of isopentane, ethyl acetate, trans-2-butene, o-xylene, and 3-ethyltoluene were 9.5,7.4, 6.4, 6.2 and 6 times those in the excellent air quality period (PM<sub>2.5</sub>≤35 μg/m<sup>3</sup>), respectively, much higher than the 1.8-fold increase of CO. In contrast, the concentrations of 1-pentene and cis-2-pentene decreased instead of increasing, dropping by 75 % and 60 %, respectively. The concentrations of typical long-lived species remained essentially stable. Source apportionment results indicated that among the 8 sources of VOCs in ambient air, the concentration contributions and proportions of 4 sources, namely vehicle emissions, gas evaporation, solvent use, and domestic sources, all increased with the elevation of PM<sub>2.5</sub> concentrations. During moderate pollution, their concentration contributions were 22.1 ppbv (34.3 %), 13.61 ppbv (21.7 %), 8.1 ppbv (11.5 %), and 7.8 ppbv (10.1 %), respectively. Among these, the concentration contribution of solvent use source during moderate pollution was 12.6 times that in the excellent air quality period, making it the source with the largest relative concentration contribution. The concentration contributions of the other 4 sources hardly changed with PM<sub>2.5</sub> concentration. This indicated that industrial emissions, as well as biomass/waste combustion sources were effectively controlled throughout the pollution process, and no secondary formation sources of VOCs were detected during the winter pollution episodes. A comparison of changes in VOC species concentrations and their sources revealed that the increase in concentrations of reactive species with PM<sub>2.5</sub> concentration was much lower than the increase in their source contributions, indicating significant chemical depletion. These findings suggested that the main sources driving the synchronous increase of PM<sub>2.5</sub> and VOC concentration in ambient air are vehicle emissions, gas evaporation, solvent use, and domestic sources. These sources not only directly emit
{"title":"Characteristics and sources of ambient VOCs under varying PM2.5 levels in winter","authors":"Rui Sun , Guiying You , Danlin Song , Miao Feng , Hefan Liu , Shaodong Xie","doi":"10.1016/j.atmosenv.2026.121826","DOIUrl":"10.1016/j.atmosenv.2026.121826","url":null,"abstract":"<div><div>To investigate the concentration, sources of volatile organic compounds (VOCs), and their impact on the formation of secondary particulate matter under different PM<sub>2.5</sub> concentration levels in ambient air, a one-month online observation of ambient VOCs and PM<sub>2.5</sub> concentrations was conducted in Chengdu, China during winter. The results showed that the concentrations of most VOC species increased significantly with the rising PM<sub>2.5</sub> concentration. The Concentration and proportions of alkenes/alkynes, halocarbons, aromatics, and oxygenated VOCs (OVOCs) all increased as PM<sub>2.5</sub> concentrations rose, with alkenes and alkynes showing a more prominent increase. However, the proportion of alkanes decreased with increasing PM<sub>2.5</sub> concentration, yet they still accounted for over 40 % of total VOCs concentrations. During moderately polluted period (PM<sub>2.5</sub>>115 μg/m<sup>3</sup>), the concentrations of isopentane, ethyl acetate, trans-2-butene, o-xylene, and 3-ethyltoluene were 9.5,7.4, 6.4, 6.2 and 6 times those in the excellent air quality period (PM<sub>2.5</sub>≤35 μg/m<sup>3</sup>), respectively, much higher than the 1.8-fold increase of CO. In contrast, the concentrations of 1-pentene and cis-2-pentene decreased instead of increasing, dropping by 75 % and 60 %, respectively. The concentrations of typical long-lived species remained essentially stable. Source apportionment results indicated that among the 8 sources of VOCs in ambient air, the concentration contributions and proportions of 4 sources, namely vehicle emissions, gas evaporation, solvent use, and domestic sources, all increased with the elevation of PM<sub>2.5</sub> concentrations. During moderate pollution, their concentration contributions were 22.1 ppbv (34.3 %), 13.61 ppbv (21.7 %), 8.1 ppbv (11.5 %), and 7.8 ppbv (10.1 %), respectively. Among these, the concentration contribution of solvent use source during moderate pollution was 12.6 times that in the excellent air quality period, making it the source with the largest relative concentration contribution. The concentration contributions of the other 4 sources hardly changed with PM<sub>2.5</sub> concentration. This indicated that industrial emissions, as well as biomass/waste combustion sources were effectively controlled throughout the pollution process, and no secondary formation sources of VOCs were detected during the winter pollution episodes. A comparison of changes in VOC species concentrations and their sources revealed that the increase in concentrations of reactive species with PM<sub>2.5</sub> concentration was much lower than the increase in their source contributions, indicating significant chemical depletion. These findings suggested that the main sources driving the synchronous increase of PM<sub>2.5</sub> and VOC concentration in ambient air are vehicle emissions, gas evaporation, solvent use, and domestic sources. These sources not only directly emit","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"370 ","pages":"Article 121826"},"PeriodicalIF":3.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026109","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 : 2026-01-21DOI: 10.1016/j.atmosenv.2026.121811
Anna Font , Joel F. de Brito , Véronique Riffault , Sébastien Conil , Jean-Luc Jaffrezo , Aude Bourin
Trends in daily PM2.5 concentrations were assessed at 5 rural background sites in France in 2014–2021, together with major particulate components which concentrations were attributed to (i) anthropogenic emissions including fossil fuels (FF) and biomass burning (BB) from primary emissions; and (ii) secondary particulate constituents including non-sea-salt sulphate, nitrate and ammonium. Annual PM2.5 concentrations correlated to annual emissions in both SO2 and NOX in France at all sites; correlations to primary PM2.5 emissions varied depending on the site. To disentangle the influence of weather, long-range transport, and the conditions controlling for PM secondary formation on the PM2.5 time series, boosted regression tree (BRT) models were built at each site for PM2.5; and normalised time series calculated by randomising the value of the explanatory variables at a given time. Two BRT models with their respective normalised PM2.5 time series were calculated: de-weathered time series (without the influence of the meteorological and long-range transport) and de-weathered & de-oxidised time series (randomisation of meteorology, transport and OX (NO2 + O3) concentrations). In 2014–2021, PM2.5 decreased at −5.6 % year−1, almost twice as fast as changes in primary emissions in France and neighbouring countries (about −3 % year−1). Overall trends in de-weathered, and de-weathered and de-oxidised PM2.5 were lower than that in PM2.5 observations, at −3.9 % year−1 and -3.2 % year−1, respectively. Trends in de-weathered & de-oxidised PM2.5 were close to those in emissions, demonstrating the role of including variables capturing the oxidative capacity of the atmosphere in the normalising techniques to compare trends in PM2.5 with primary emissions. Faster downward rates in PM2.5 aerosols in rural background in mainland France were mostly associated with the decrease in gas emissions responsible for secondary particles and less sensitive to changes in primary emissions. Control of NH3 emissions is suggested to be crucial to ensure downward trends in PM2.5 at the regional background environments to reduce concentrations closer to WHO limits.
{"title":"Do regional background sites capture changes in primary PM2.5 emissions at the national scale? Recent trends in PM2.5 in rural environments in metropolitan France","authors":"Anna Font , Joel F. de Brito , Véronique Riffault , Sébastien Conil , Jean-Luc Jaffrezo , Aude Bourin","doi":"10.1016/j.atmosenv.2026.121811","DOIUrl":"10.1016/j.atmosenv.2026.121811","url":null,"abstract":"<div><div>Trends in daily PM<sub>2.5</sub> concentrations were assessed at 5 rural background sites in France in 2014–2021, together with major particulate components which concentrations were attributed to (i) anthropogenic emissions including fossil fuels (FF) and biomass burning (BB) from primary emissions; and (ii) secondary particulate constituents including non-sea-salt sulphate, nitrate and ammonium. Annual PM<sub>2.5</sub> concentrations correlated to annual emissions in both SO<sub>2</sub> and NO<sub>X</sub> in France at all sites; correlations to primary PM<sub>2.5</sub> emissions varied depending on the site. To disentangle the influence of weather, long-range transport, and the conditions controlling for PM secondary formation on the PM<sub>2.5</sub> time series, boosted regression tree (BRT) models were built at each site for PM<sub>2.5</sub>; and normalised time series calculated by randomising the value of the explanatory variables at a given time. Two BRT models with their respective normalised PM<sub>2.5</sub> time series were calculated: de-weathered time series (without the influence of the meteorological and long-range transport) and de-weathered & de-oxidised time series (randomisation of meteorology, transport and O<sub>X</sub> (NO<sub>2</sub> + O<sub>3</sub>) concentrations). In 2014–2021, PM<sub>2.5</sub> decreased at −5.6 % year<sup>−1</sup>, almost twice as fast as changes in primary emissions in France and neighbouring countries (about −3 % year<sup>−1</sup>). Overall trends in de-weathered, and de-weathered and de-oxidised PM<sub>2.5</sub> were lower than that in PM<sub>2.5</sub> observations, at −3.9 % year<sup>−1</sup> and -3.2 % year<sup>−1</sup>, respectively. Trends in de-weathered & de-oxidised PM<sub>2.5</sub> were close to those in emissions, demonstrating the role of including variables capturing the oxidative capacity of the atmosphere in the normalising techniques to compare trends in PM<sub>2.5</sub> with primary emissions. Faster downward rates in PM<sub>2.5</sub> aerosols in rural background in mainland France were mostly associated with the decrease in gas emissions responsible for secondary particles and less sensitive to changes in primary emissions. Control of NH<sub>3</sub> emissions is suggested to be crucial to ensure downward trends in PM<sub>2.5</sub> at the regional background environments to reduce concentrations closer to WHO limits.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"370 ","pages":"Article 121811"},"PeriodicalIF":3.7,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026108","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}
This study presents novel observations of phosphorus, primary sugars, sugar alcohols and anhydro saccharides in fine atmospheric aerosols (PM2.5) in Athens, Greece, one of the largest cities in the eastern Mediterranean, obtained through multi-year sampling from Dec. 2018 to July 2021 (20 months in total). It also leverages additional aerosol composition data to identify and attribute P levels to natural and anthropogenic sources through receptor modeling. Total sugars concentrations had a median of 205 ng m−3 and varied from 12.6 to 3391 ng m−3, with primary sugars, sugar alcohols and anhydro saccharides contributing 22 %, 19 % and 59 %, respectively. The median total P (TP) concentration was 21.0 ng m−3 (2.64–179 ng m−3) during the study period. On average, sugars contributed 2.6 % to organic carbon and 4.9 % to water soluble organic carbon. Positive Matrix Factorization analysis (PMF) showed that bioaerosols were the major contributors (31 %) of TP, followed by traffic/resuspension (28 %), Sahara dust (19 %), regional transport (14 %) and sea salt (6 %). In addition, bioaerosols (fungi and pollen) contributed by ∼21 % to total PM2.5 mass. Overall natural sources accounted for approximately 50 % of the total PM2.5 mass, that is a notable finding highlighting the significant impact of non-anthropogenic sources on ambient PM2.5.
本研究通过2018年12月至2021年7月（共20个月）的多年采样，对地中海东部最大城市之一希腊雅典的细颗粒物（PM2.5）中的磷、原糖、糖醇和无水糖进行了新的观测。它还利用额外的气溶胶成分数据，通过受体模拟来确定P水平并将其归因于自然和人为来源。总糖浓度的中位数为205 ng m - 3，变化范围为12.6至3391 ng m - 3，其中原糖、糖醇和无水糖分别贡献了22%、19%和59%。研究期间总磷（TP）浓度中位数为21.0 ng m−3 （2.64 ~ 179 ng m−3）。平均而言，糖贡献了2.6%的有机碳和4.9%的水溶性有机碳。正矩阵分解分析（PMF）表明，生物气溶胶是总磷的主要贡献者（31%），其次是交通/再悬浮（28%）、撒哈拉沙尘（19%）、区域运输（14%）和海盐（6%）。此外，生物气溶胶（真菌和花粉）对PM2.5总质量的贡献约为21%。总体而言，自然源约占PM2.5总质量的50%，这是一个值得注意的发现，突出了非人为源对环境PM2.5的重大影响。
{"title":"Bioaerosols and phosphorus in PM2.5 in a major Eastern Mediterranean city","authors":"Kyriaki Papoutsidaki , Konstantina Oikonomou , Maria Tsagkaraki , Georgios Grivas , Kalliopi Tavernaraki , Faidra-Aikaterini Kozonaki , Irini Tsiodra , Aikaterini Bougiatioti , Nikos Mihalopoulos , Maria Kanakidou","doi":"10.1016/j.atmosenv.2026.121813","DOIUrl":"10.1016/j.atmosenv.2026.121813","url":null,"abstract":"<div><div>This study presents novel observations of phosphorus, primary sugars, sugar alcohols and anhydro saccharides in fine atmospheric aerosols (PM<sub>2.5</sub>) in Athens, Greece, one of the largest cities in the eastern Mediterranean, obtained through multi-year sampling from Dec. 2018 to July 2021 (20 months in total). It also leverages additional aerosol composition data to identify and attribute P levels to natural and anthropogenic sources through receptor modeling. Total sugars concentrations had a median of 205 ng m<sup>−3</sup> and varied from 12.6 to 3391 ng m<sup>−3</sup>, with primary sugars, sugar alcohols and anhydro saccharides contributing 22 %, 19 % and 59 %, respectively. The median total P (TP) concentration was 21.0 ng m<sup>−3</sup> (2.64–179 ng m<sup>−3</sup>) during the study period. On average, sugars contributed 2.6 % to organic carbon and 4.9 % to water soluble organic carbon. Positive Matrix Factorization analysis (PMF) showed that bioaerosols were the major contributors (31 %) of TP, followed by traffic/resuspension (28 %), Sahara dust (19 %), regional transport (14 %) and sea salt (6 %). In addition, bioaerosols (fungi and pollen) contributed by ∼21 % to total PM<sub>2.5</sub> mass. Overall natural sources accounted for approximately 50 % of the total PM<sub>2.5</sub> mass, that is a notable finding highlighting the significant impact of non-anthropogenic sources on ambient PM<sub>2.5</sub>.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"370 ","pages":"Article 121813"},"PeriodicalIF":3.7,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146075937","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 : 2026-01-20DOI: 10.1016/j.atmosenv.2026.121809
Jinwen Li , Shaoxun Guo , Yongcheng Jia , Tianzeng Chen , Wei Ma , Veli-Matti Kerminen , Tuukka Petäjä , Markku Kulmala , Hui Li , Yongchun Liu
Coupling effects among different components of atmospheric particulate matter (PM) may influence the oxidative potential (OP) of PM, whereas the mechanism remains unclear. In this study, we investigate the OP of binary organics/inorganics mixtures, typically present in PM, using a dithiothreitol assay under dark conditions. The binary mixture of 2-methoxyphenol (2-MET, a typical biomass burning marker) and FeCl3 shows a 23 times increase in OP (380 pmol min−1·μg−1) compared to the individual species. A synergistic mechanism has been revealed through comprehensive characterization of reactive oxygen species (ROS) and relevant intermediates, by ROS probe technology, spectroscopy, and mass spectrometry. Mass spectrometry indicates that diphenyl-p-benzoquinones, like 5,5′-dihydroxy-3,3′-dimethoxy-[1,1′-bi(cyclohexane)]-2,2′,5,5′-tetraene-4,4′-dione, can be produced in the presence of Fe3+, subsequently promoting ROS formation (·OH and ·O2−) through free radical chain reaction induced by semiquinone. The OP achieves a maximum when the mass ratio of 2-MET to FeCl3 is 1.0 at 37°C. It persists around 60% of the initial OP over 31 h, which indicates the possible contribution of the mixture of methoxyphenol and Fe(III) to environmental persistent free radicals in the atmosphere. Our findings provide a new insight into the non-linear dependence of PM oxidative toxicity on composition and meaningful guidance for future PM health risk reduction.
{"title":"Enhanced oxidative potential of methoxyphenol in the presence of Fe(III) in the atmosphere: Effects and mechanisms","authors":"Jinwen Li , Shaoxun Guo , Yongcheng Jia , Tianzeng Chen , Wei Ma , Veli-Matti Kerminen , Tuukka Petäjä , Markku Kulmala , Hui Li , Yongchun Liu","doi":"10.1016/j.atmosenv.2026.121809","DOIUrl":"10.1016/j.atmosenv.2026.121809","url":null,"abstract":"<div><div>Coupling effects among different components of atmospheric particulate matter (PM) may influence the oxidative potential (OP) of PM, whereas the mechanism remains unclear. In this study, we investigate the OP of binary organics/inorganics mixtures, typically present in PM, using a dithiothreitol assay under dark conditions. The binary mixture of 2-methoxyphenol (2-MET, a typical biomass burning marker) and FeCl<sub>3</sub> shows a 23 times increase in OP (380 pmol min<sup>−1</sup>·μg<sup>−1</sup>) compared to the individual species. A synergistic mechanism has been revealed through comprehensive characterization of reactive oxygen species (ROS) and relevant intermediates, by ROS probe technology, spectroscopy, and mass spectrometry. Mass spectrometry indicates that diphenyl-p-benzoquinones, like 5,5′-dihydroxy-3,3′-dimethoxy-[1,1′-bi(cyclohexane)]-2,2′,5,5′-tetraene-4,4′-dione, can be produced in the presence of Fe<sup>3+</sup>, subsequently promoting ROS formation (·OH and ·O<sub>2</sub><sup>−</sup>) through free radical chain reaction induced by semiquinone. The OP achieves a maximum when the mass ratio of 2-MET to FeCl<sub>3</sub> is 1.0 at 37°C. It persists around 60% of the initial OP over 31 h, which indicates the possible contribution of the mixture of methoxyphenol and Fe(III) to environmental persistent free radicals in the atmosphere. Our findings provide a new insight into the non-linear dependence of PM oxidative toxicity on composition and meaningful guidance for future PM health risk reduction.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"369 ","pages":"Article 121809"},"PeriodicalIF":3.7,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036628","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 : 2026-01-19DOI: 10.1016/j.atmosenv.2026.121800
Dong Ding , Kai Kang , Shaofang Li , Tianfang Xing , Wenjie Yang , Liuqiao Sun , Xinxin Liu , Yao Chen , Mingyi Xue , Zengli Yu , Zhan Gao
Background
Globally, the increasing frequency of extreme heat events and ozone pollution incidents has significantly intensified public health risks. However, empirical evidence regarding their synergistic impacts remains limited in central China.
Methods
A two-stage analysis was conducted using data from 121 counties in Henan (2013–2019). Quasi-Poisson generalized additive models were used to assess county-specific associations, adjusting for PM2.5, RH, and temporal trends. The combined effect of air temperature (non-linear) and ozone (linear) was captured through multiplicative interaction terms. Random-effects meta-analyses were applied to pool the results. Subgroup analyses examined differences by age, sex, marital status, and cause of death.
Results
During the study period, 1,280,429 deaths were recorded. Both high temperatures and elevated ozone levels were associated with increased mortality. Their joint effects were stronger than individual exposures. At high ozone levels, mortality risk increased by 2 percentage points (from 9.3 % to 11.3 %) between temperature distribution percentiles 75th and 99th. Under high-temperature conditions (31.4 °C, 90th percentile), a 10 μg/m3 elevation in ozone was associated with a 0.94 % (95 % CI: 0.49 %–1.38 %) increase in mortality. Older adults, females, other marital statuses (including unmarried, divorced, or widowed), and those with cardiovascular or respiratory diseases were more susceptible to its effects.
Conclusion
High temperature and ozone synergistically increase mortality risk. Targeted interventions are needed to protect vulnerable groups under climate change.
{"title":"Joint impact of heat and ozone exposure on mortality in Henan, central China","authors":"Dong Ding , Kai Kang , Shaofang Li , Tianfang Xing , Wenjie Yang , Liuqiao Sun , Xinxin Liu , Yao Chen , Mingyi Xue , Zengli Yu , Zhan Gao","doi":"10.1016/j.atmosenv.2026.121800","DOIUrl":"10.1016/j.atmosenv.2026.121800","url":null,"abstract":"<div><h3>Background</h3><div>Globally, the increasing frequency of extreme heat events and ozone pollution incidents has significantly intensified public health risks. However, empirical evidence regarding their synergistic impacts remains limited in central China.</div></div><div><h3>Methods</h3><div>A two-stage analysis was conducted using data from 121 counties in Henan (2013–2019). Quasi-Poisson generalized additive models were used to assess county-specific associations, adjusting for PM<sub>2</sub>.<sub>5</sub>, RH, and temporal trends. The combined effect of air temperature (non-linear) and ozone (linear) was captured through multiplicative interaction terms. Random-effects meta-analyses were applied to pool the results. Subgroup analyses examined differences by age, sex, marital status, and cause of death.</div></div><div><h3>Results</h3><div>During the study period, 1,280,429 deaths were recorded. Both high temperatures and elevated ozone levels were associated with increased mortality. Their joint effects were stronger than individual exposures. At high ozone levels, mortality risk increased by 2 percentage points (from 9.3 % to 11.3 %) between temperature distribution percentiles 75th and 99th. Under high-temperature conditions (31.4 °C, 90th percentile), a 10 μg/m<sup>3</sup> elevation in ozone was associated with a 0.94 % (95 % CI: 0.49 %–1.38 %) increase in mortality. Older adults, females, other marital statuses (including unmarried, divorced, or widowed), and those with cardiovascular or respiratory diseases were more susceptible to its effects.</div></div><div><h3>Conclusion</h3><div>High temperature and ozone synergistically increase mortality risk. Targeted interventions are needed to protect vulnerable groups under climate change.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"369 ","pages":"Article 121800"},"PeriodicalIF":3.7,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036627","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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