Atmospheric Environment最新文献

{"title":"Links between atmospheric aerosols and sea state in the Arctic Ocean","authors":"Alireza Moallemi ,&nbsp;Alberto Alberello ,&nbsp;Iris Thurnherr ,&nbsp;Guangyu Li ,&nbsp;Zamin A. Kanji ,&nbsp;Filippo Bergamasco ,&nbsp;Roman Pohorsky ,&nbsp;Filippo Nelli ,&nbsp;Alessandro Toffoli ,&nbsp;Julia Schmale","doi":"10.1016/j.atmosenv.2024.120844","DOIUrl":"10.1016/j.atmosenv.2024.120844","url":null,"abstract":"<div><div>Sea spray emission is the largest mass flux of aerosols to the atmosphere with important impact on atmospheric radiative transfer. However, large uncertainties still exit in constraining this mass flux and its climate forcing, in particular in the Arctic, where sea ice and relatively low wind speed in summer constitute a significantly different regime compared to the global ocean. Sea state conditions and marine boundary layer stability are also critical variables, but their contribution is often overlooked. Here we present concurrent observations of sea state using a novel stereo camera system, of sea spray through coarse mode aerosols, and of meteorological variables to determine boundary layer stability in the Barents and Kara Seas during the 2021 Arctic Century Expedition. Our findings reveal that aerosol concentrations were highest over open waters, closely correlating with wave height, followed by wind speed, wave steepness, and wave age. Notably, these correlations were stronger under unstable marine boundary layer conditions, reflecting immediate sea spray generation. By analysing various combinations of sea and atmospheric variables, we identified the wave height Reynolds number as the most effective indicator of atmospheric sea spray concentration, explaining 57% of its variability in unstable conditions. Our study underscores the need to consider sea state, wind, and boundary layer conditions together to accurately estimate atmospheric sea spray concentrations in the Arctic.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120844"},"PeriodicalIF":4.2,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characteristics of light absorption and environmental effects of Brown carbon aerosol in Chongqing during summer and winter based on online measurement: Implications of secondary formation","authors":"Hong Wu ,&nbsp;Chao Peng ,&nbsp;Tianyu Zhai ,&nbsp;Jingcheng Deng ,&nbsp;Peili Lu ,&nbsp;Zhenliang Li ,&nbsp;Yang Chen ,&nbsp;Mi Tian ,&nbsp;Zhier Bao ,&nbsp;Xin Long ,&nbsp;Fumo Yang ,&nbsp;Chongzhi Zhai","doi":"10.1016/j.atmosenv.2024.120843","DOIUrl":"10.1016/j.atmosenv.2024.120843","url":null,"abstract":"<div><div>Light-absorbing organic carbon (i.e., brown carbon, BrC) significantly contributes to light absorption and radiative forcing in the atmospheric particles. However, the secondary formation of BrC and optical properties of secondary BrC are poorly understood. In this study, we analyzed and evaluated the light absorption and environmental effects of BrC and secondary BrC from July 1st to 31st, 2022 (summer) and January 20th to February 20th, 2023 (winter) in Chongqing. BrC and secondary BrC light absorption were estimated via a seven-wavelength aethalometer and the statistical approach. The average values of secondary BrC light absorption (Abs_BrC,sec,λ) accounted for 46.2–56.5% of Abs_BrC. Abs_BrC,370 and Abs_BrC,sec,370 were significantly higher during winter (26.2 ± 13.2 and 9.1 ± 5.2 Mm⁻¹ respectively) than that during summer (7.2 ± 4.1 and 5.2 ± 3.5 Mm⁻¹ respectively) (<em>p</em> &lt; 0.001), suggesting secondary formation played an essential role in BrC. A diurnal cycle of Abs_BrC,sec,370 was explained by the photobleaching of light-absorbing chromophores under the oxidizing conditions in the daytime, and the formation of chromophores via aqueous reactions with NH₄⁺ and NO_x after sunset during winter. PSCF analysis showed that transport of anthropogenic emissions from the northeastern and southeastern areas of Chongqing was the important source of the secondary BrC in PP during winter. During winter, the average values of SFE_BrC and SFE_BrC,sec were 31.9 and 27.4 W g⁻¹ lower than that during summer (64.7 and 44.5 W g⁻¹), respectively. In contrast, J[NO₂] values of SFE_BrC and SFE_BrC,sec decreased by 23.3% and 8.7% during winter higher than that during summer (19.9% and 5.6%), indicating that BrC and secondary BrC cause substantial radiative effects and atmospheric photochemistry. Overall, this study is helpful in understanding the characterization and secondary formation of BrC and accurately evaluating the environmental effects of BrC in Chongqing.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120843"},"PeriodicalIF":4.2,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358962","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}

{"title":"Morphology and elemental composition of individual solid dust particles: From different sources to the atmosphere","authors":"Wenhua Wang ,&nbsp;Mengyang Wang ,&nbsp;Longyi Shao ,&nbsp;Xiuyan Zhou ,&nbsp;Zhe Zhao ,&nbsp;Na Li ,&nbsp;Hui Zhou ,&nbsp;Weijun Li","doi":"10.1016/j.atmosenv.2024.120842","DOIUrl":"10.1016/j.atmosenv.2024.120842","url":null,"abstract":"<div><div>This study investigates the morphology and elemental composition of individual solid dust particles from various sources (e.g., thermal power plant, domestic coal combustion, building construction dust, wind-blown dust, Asian dust storm, and road related dust) to the atmosphere under high and low relative humidity (RH) conditions in a coastal city of north China by using high-resolution electron microscopes. The results showed that distinct variations between dust particles from thermal power plant and domestic coal combustion, despite both using coal as fuel. Specifically, 88.6% (by number) of thermal power plant particles were spherical, whereas only 2 out of 347 particles from domestic coal combustion exhibited a spherical shape. Furthermore, domestic coal combustion particles showed a higher proportion of Ca-rich particles compared to those from thermal power plant. The wind-blown dust and Asian dust storm particles were mainly “Si + Al” subtype (52.0% v.s. 75.3%) and Si-dominant subtype (16.4% v.s. 11.7%) particles, which were mainly from crustal sources. However, wind-blown dust contained a higher fraction of Ca-rich (11.6%) and Fe-rich (5.3%) particles than Asian dust. The building construction dust particles primarily consisted of irregular Ca-dominant (39.4%) and “Ca + Si” subtype (29.8%) particles. Road related dust were also mainly Si-rich particles (52.9%), likely from re-suspended soil, along with a notable presence of spherical (8.0%) and Fe-rich particles (19.3%), possibly linked to vehicle emissions and brake wear. Additionally, relative number percentage of Na-rich particles and the average weigh ratios of Na in the atmospheric particles were higher than those from all above-mentioned source samples, suggesting that sea-salt related particles might be an important source of the atmospheric dust at the coastal city. The results indicated that Ca-rich particles were significantly modified by S and NaCl particles might lose Cl through heterogeneous reactions under higher RH.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120842"},"PeriodicalIF":4.2,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324213","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}

{"title":"In silico modelling of radiative efficiencies of anthropogenic greenhouse gases","authors":"Daniela Alvarado-Jiménez ,&nbsp;Nicola Tasinato","doi":"10.1016/j.atmosenv.2024.120839","DOIUrl":"10.1016/j.atmosenv.2024.120839","url":null,"abstract":"<div><div>Radiative efficiency (RE) is a climate metric adopted in international reports on climate change to quantify the greenhouse capacity of gases, and hence to guide decision-making processes and drive transitions in the production and utilization of chemicals in different application fields. Key quantities for the determination of the RE of a gas are the atmospheric irradiance profile and the infrared (IR) absorption cross section spectrum. The latter is usually measured experimentally, even though acquiring high-quality IR spectra can pose severe challenges, sometimes limiting the accuracy or the accessible spectral range. While computational quantum chemistry methods have emerged as valuable tools to simulate IR absorption properties, their application to REs estimation is still limited to the use of the double-harmonic approximation, which presents fundamental limitations. In this work, a cost-effective quantum chemical (QC) workflow including non-empirical anharmonic contributions to spectral properties and an automatic identification of conformer distribution is presented for the accurate evaluation of REs using a range of atmospheric irradiance profiles. Different levels of theory are considered, according to the current state-of-the-art, and the accuracy of the QC RE tool is demonstrated with reference to a number of representative halocarbons widely used in refrigeration, manufacturing, and pharmaceutical fields. The results show that REs can be computed with an average accuracy of 5% using double-hybrid functionals, which overshoot the widely used B3LYP method. Finally, the QC methodology is applied to determine the REs of selected halocarbons for which data is limited, or to address some contradictory results appeared in the literature for some species. The outcomes of this work demonstrate that QC anharmonic IR cross section spectra can be used to estimate REs with an accuracy on par with that of experimental measurements, hence applicable to challenging cases for providing data for policymakers as well for screening purposes when seeking new replacement compounds.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120839"},"PeriodicalIF":4.2,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Total deposition of sulphur to coniferous forests in Sweden - Taking canopy exchange into account","authors":"G. Pihl Karlsson ,&nbsp;P.E. Karlsson ,&nbsp;S. Hellsten ,&nbsp;H. Danielsson ,&nbsp;V. Kronnäs ,&nbsp;C. Akselsson","doi":"10.1016/j.atmosenv.2024.120840","DOIUrl":"10.1016/j.atmosenv.2024.120840","url":null,"abstract":"<div><div>In the low deposition situation of today at many of the long-term Swedish forest monitoring sites, the deposition measured as precipitation to the open field, i.e. bulk deposition of oxidized sulphur (S) is often higher or equal to deposition of S sampled under the forest canopies, i.e. as throughfall. This suggests that the total S deposition estimated using throughfall is underestimated. The reason for this is direct exchange of S with the forest canopies, leading to an underestimation which becomes evident in low-deposition areas. We describe a new method to estimate the dry deposition of S to coniferous forest based on measurements with Teflon string samplers as surrogate surfaces, in combination with measurements of the net throughfall for sodium (throughfall subtracted with wet deposition). The wet deposition was estimated from bulk deposition measurements on the open field, corrected for dry deposition to the collectors. The method was applied for Norway spruce forests at monitoring sites across Sweden during nine years 2014–2022, and total deposition was calculated based on wet deposition and the estimated dry deposition. The estimated annual total deposition of S as a mean value for coniferous forests ranged between 0.8 and 5.2 kg S ha⁻¹ yr⁻¹ with lowest values in northern Sweden and highest in southwest Sweden. The share of dry deposition of the total S deposition was between 20 and 53%. The mean annual deposition of S measured as throughfall during 2014–2022 for three different regions in Sweden was between 16 and 41% lower compared to the corresponding total deposition estimated with the new method. The canopy exchange of S was analyzed on a monthly basis as the difference between the estimated total deposition and the measured throughfall deposition of S. At most sites, there was a canopy uptake of S during the summer months and a leakage of S during the winter months. This indicates that the canopy exchange of S is a phenomenon that involves some biological activity.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120840"},"PeriodicalIF":4.2,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive evaluation of the atmospheric impacts and health risks of cooking fumes from different cuisines","authors":"Junfeng Zhang ,&nbsp;Wenjiao Duan ,&nbsp;Shuiyuan Cheng ,&nbsp;Chuanda Wang","doi":"10.1016/j.atmosenv.2024.120837","DOIUrl":"10.1016/j.atmosenv.2024.120837","url":null,"abstract":"<div><div>Pollutants emitted by catering enterprises pose a significant threat to the environment and public health. In this study, based on a systematic analysis of volatile organic compound (VOC) emission characteristics of different cuisines, the contribution of cooking emissions from catering enterprises to the PM_2.5 and O₃ concentrations in the atmosphere was evaluated using generation potential calculations and WRF-CAMx simulations. The health exposure risks of VOCs in kitchen breathing areas and those of PM_2.5 and O₃ contributed by the catering enterprises were evaluated. The generation potential calculation results showed that the catering enterprises exhibit 2.21–5.00 gO₃/gVOCs of ozone formation potential (OFP) and 0.07–0.21 gSOA/gVOCs of secondary organic aerosol production potential (SOAP). The WRF-CAMx simulation results indicated that cooking emissions from catering enterprises contribute 0.36–1.91 μg/m³ and 0.05–0.21 μg/m³ to PM_2.5 and maximum daily 8-h average (MDA8) concentrations of O₃. The health exposure risks of PM_2.5 and O₃ were higher in catering enterprises in southern cities than in northern cities and were higher in urban areas than in suburban areas. The average hazardous VOCs (HVOCs) concentrations ranged from 53 ± 16 to 357 ± 31 μg/m³ in kitchen breathing areas. Acrolein was the primary contributor to the hazard index (HI) of all VOC species, accounting for 50.9%–99.5%. The total incremental lifetime carcinogenic risk (ILCR) of all cuisines exceeded the acceptable thresholds of 1.00 × 10⁻⁶. These findings provide insights that can aid in the formation and implementation of pollutant mitigation strategies in the catering industry.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120837"},"PeriodicalIF":4.2,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421622","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}

{"title":"Controls on the stable Mo isotopic composition of inner-continental precipitation","authors":"E.M. O'Sullivan ,&nbsp;A.K.C. Kaufmann ,&nbsp;C. Rosca ,&nbsp;M.G. Babechuk ,&nbsp;M.C. Pierret ,&nbsp;N.H. Waber ,&nbsp;T.F. Nägler","doi":"10.1016/j.atmosenv.2024.120838","DOIUrl":"10.1016/j.atmosenv.2024.120838","url":null,"abstract":"<div><div>The molybdenum (Mo) isotope budget of the surface environment has been well characterized in recent decades, facilitating accurate mass balance modeling of the ancient redox-driven Mo cycle. One yet unresolved component is the range of possible processes and sources that result in isotopically heavy river waters relative to continental sources. Following a recent hypothesis that isotopically heavy δ⁹⁸Mo of precipitation may control the final δ⁹⁸Mo of river water relative to its continental source bedrock, we investigated the δ⁹⁸Mo composition of 19 snow samples from three locations in Central Europe: the Swiss Alps (“Alpine” samples) from the Hochalpine Forschungsstation Jungfraujoch (HFSJ) in both summer and winter, the Swiss Jura Mountains in winter and the French Vosges Mountains in winter. Stream waters from two snowmelt-fed streams were additionally collected from the Alpine site. Snow sample δ⁹⁸Mo compositions were highly variable, ranging from −0.03 to +1.93 ‰, with no clear mixing trends indicating complex sources, source pathways, or post-depositional processing. Only the winter snow samples from the high-altitude HFSJ site had δ⁹⁸Mo values consistently heavier than typical continental crust. The δ⁹⁸Mo results were coupled with radiogenic Sr isotopic, major ion, and trace element compositions as tracers for three major sources of airborne ion inputs: sea salt, mineral dust, and anthropogenic aerosols. We found that the most likely source of Mo to precipitation in the lower elevation Vosges and Jura Mountains samples was isotopically light soil mineral dust, which reflected the underlying bedrock sources, with a likely additional anthropogenic component. The isotopically heavy winter snow samples at the elevated HFSJ site were attributed to a higher input of carbonate mineral dust from long-distance transport of carbonate-rich Saharan dust, which was overwritten in the summer by an influx of low elevation sources transported upwards during higher vertical thermal mixing. Finally, we concluded that precipitation has a negligible direct effect on the overall Mo content and isotopic composition of inner continental European streams and rivers relative to other sources, such as bedrock weathering. Future time-series studies may augment these conclusions to show possible heterogeneity of precipitation as well as the addition of sample sites closer to marine sources, where a larger flux of isotopically heavy marine aerosols to streams might be expected.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120838"},"PeriodicalIF":4.2,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324212","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}

{"title":"Comparative analysis of winter composite-PM2.5 in Central Indo Gangetic Plain cities: Combined organic and inorganic source apportionment and characterization, with a focus on the photochemical age effect on secondary organic aerosol formation","authors":"Akanksha Lakra ,&nbsp;Ashutosh Kumar Shukla ,&nbsp;Himadri Sekhar Bhowmik ,&nbsp;Amit Kumar Yadav ,&nbsp;Vaishali Jain ,&nbsp;Vishnu Murari ,&nbsp;Sreenivas Gaddamidi ,&nbsp;Vipul Lalchandani ,&nbsp;Sachchida Nand Tripathi","doi":"10.1016/j.atmosenv.2024.120827","DOIUrl":"10.1016/j.atmosenv.2024.120827","url":null,"abstract":"<div><div>To gain insights into air quality dynamics, a high-end instrument such as High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) alongside an Aethalometer was used to measure the Composite PM_2.5 (C-PM_2.5) in Lucknow and Kanpur during winter. It encompasses non-refractive PM_2.5 (NR-PM_2.5) and Black Carbon (BC) mass concentrations. Significant variation was noted in average C-PM_2.5 concentrations at both sites, as 168.8 ± 61.3 μg m⁻³ in Lucknow and 90.7 ± 25.7 μg m⁻³ in Kanpur. Organics emerged as the predominant component, constituting ∼55%–65% of the C-PM_2.5 mass, followed by inorganics (24% and 30%) and BC (20% and 8%). The present study employs Positive Matrix Factorization (PMF) on combined organic and inorganic source apportionment, resolving eight and seven source factors at Lucknow and Kanpur, respectively. Both sites exhibit significant contributions from solid-fuel combustion organic aerosol (SFC-OA), with ∼11% in Lucknow and 8% in Kanpur. However, SFC-OA mass concentration in Lucknow, at 24.67 μg m^-³, is nearly double that in Kanpur (12.05 μg m^-³). This was likely due to domestic coal burning in the nearby households, unregulated open burning, and burning of garbage on roadsides. The study shows that both sites were affected by oxidized biomass burning OA (O-BBOA) emissions, with increased concentration during the night due to dark oxidation by NO₃ radicals. The diurnal variation of secondary organic aerosols (SOA), such as O-BBOA and semi-volatile oxygenated OA (SVOOA), shows increasing concentration during daytime hours. Therefore, the photochemical aging (t_a) role in SOA formation was analyzed, and it was revealed that the formation might primarily be driven by photochemical oxidation. Additionally, two inorganic-rich factors, sulfate and nitrate-related OA (SO₄-OA and NO₃-OA) at both sites and additional ammonium chloride-related OA (NH₄Cl-OA) resolved at Lucknow. Our study shows that NO₃-OA and SO₄-OA formation was dominated by aqueous phase processes due to high relative humidity and decline in concentration with increasing t_a (t_a &gt; 30 h) during winter.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120827"},"PeriodicalIF":4.2,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358963","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}

{"title":"Well-planned greenery improves air urban quality - Modelling the effect of altered airflow and pollutant deposition","authors":"Malin S.M. Gustafsson ,&nbsp;Jenny Lindén ,&nbsp;Emelie M.M. Johansson ,&nbsp;Ågot K. Watne ,&nbsp;Johan Uddling ,&nbsp;Daniel Sjölie ,&nbsp;Håkan Pleijel","doi":"10.1016/j.atmosenv.2024.120829","DOIUrl":"10.1016/j.atmosenv.2024.120829","url":null,"abstract":"<div><div>Urban air quality is influenced by vegetation through alterations in airflow and pollutant deposition processes. We investigated these interactions by integrating the Vegetation Impact Dynamic Assessment model (VIDA) with the Large-Eddy Simulation model PALM. Our analysis focus on nitrogen dioxide (NO₂) and particulate matter (PM) concentrations at the local scale, considering three tree genera. Our findings reveal the necessity of accounting for both gaseous pollutants and particles separately due to their differing mechanisms of deposition onto leaves. The coupled PALM-VIDA model demonstrates a significant reduction in PM levels across the modelling domain and within street canyons when deposition to vegetation is incorporated. Reduction in NO₂ through deposition to vegetation is lower but human NO₂ exposure can still be decreased if tree species selection and placement leads to desirable effects on air flow. Sparse tree arrangements or species with sparse crowns facilitate ventilation and are often better at reducing NO₂ concentrations in street canyons compared to denser vegetation with higher deposition but negative effects on ventilation. Our study informs urban planning and green infrastructure design, underscoring the multifaceted role of urban greenery in air pollution mitigation strategies. Its main conclusion is that both deposition processes and the influence of air mixing and ventilation need to be considered to accurately assess the effects of urban trees on local air quality. Ill-considered placement and species selection may cause a net increase in pollutants underneath the trees. However, careful planning can address this risk and instead improve overall air quality.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120829"},"PeriodicalIF":4.2,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of the 2020 COVID-19 lockdown on the concentration of non-methane volatile organic compounds in a UK urban atmosphere","authors":"Emmanuel Bernard ,&nbsp;Rebecca L. Cordell ,&nbsp;Robert S. Blake ,&nbsp;Michael J. Wilde ,&nbsp;Paul S. Monks","doi":"10.1016/j.atmosenv.2024.120836","DOIUrl":"10.1016/j.atmosenv.2024.120836","url":null,"abstract":"<div><div>The changes in air quality brought about by the COVID-19 lockdowns can provide valuable insight into how longer-term reductions in emissions might affect atmospheric composition. In urban Leicester UK, the 2020 COVID “lockdown” brought about several notable changes in atmospheric composition, including a considerable decrease (20–60%) in concentrations of non-methane volatile organic compounds (NMVOCs). Given their varied emission sources and lifetimes, NMVOC data can give valuable insights into how behavioural change impact atmospheric composition. The total concentration of 48 NMVOCs at roadside (RS) sites decreased from a pre-lockdown (sampled 16th-24th March 2020) concentration of 181.3 ± 41.4 μg/m³ to 82.0 ± 12.8 μg/m³ during lockdown (LD, sampled 18th-21st May 2020), before rebounding to a concentration of 236.3 ± 23.9 μg/m³ post lockdown (post-LD, sampled 14th-17th Sept 2020). A similar pattern was observed at urban background (UB) sites with concentrations reducing during lockdown to 96.8 ± 39.5 μg/m³ from a pre-lockdown (pre-LD) concentration of 123.2 ± 24.6 μg/m³ and then increasing to 168.6 ± 29.1 μg/m³ post-LD.</div><div>Generally, despite the decrease in NMVOC concentrations during the LD, an increase in <span><math><mrow><msub><mi>O</mi><mn>3</mn></msub></mrow></math></span> level was observed. This was attributed to decreased emissions of <span><math><msub><mtext>NO</mtext><mi>x</mi></msub></math></span> and the subsequent repartioning of O_x. This research assessed the quantitative effect of changes in vehicular and related anthropogenic emissions on air quality, providing valuable insights for the formulation of future air pollution controls.</div></div>","PeriodicalId":250,"journal":{"name":"Atmospheric Environment","volume":"338 ","pages":"Article 120836"},"PeriodicalIF":4.2,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1352231024005119/pdfft?md5=cf6a6f83dd3cbf38f5a0ec4177ea61ea&pid=1-s2.0-S1352231024005119-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}