Atmospheric Chemistry and Physics最新文献

{"title":"Ammonium-adduct chemical ionization to investigate anthropogenic oxygenated gas-phase organic compounds in urban air.","authors":"Peeyush Khare, Jordan E Krechmer, Jo Ellen Machesky, Tori Hass-Mitchell, Cong Cao, Junqi Wang, Francesca Majluf, Felipe Lopez-Hilfiker, Sonja Malek, Will Wang, Karl Seltzer, Havala O T Pye, Roisin Commane, Brian C McDonald, Ricardo Toledo-Crow, John E Mak, Drew R Gentner","doi":"10.5194/acp-22-14377-2022","DOIUrl":"10.5194/acp-22-14377-2022","url":null,"abstract":"<p><p>Volatile chemical products (VCPs) and other non-combustion-related sources have become important for urban air quality, and bottom-up calculations report emissions of a variety of functionalized compounds that remain understudied and uncertain in emissions estimates. Using a new instrumental configuration, we present online measurements of oxygenated organic compounds in a U.S. megacity over a 10-day wintertime sampling period, when biogenic sources and photochemistry were less active. Measurements were conducted at a rooftop observatory in upper Manhattan, New York City, USA using a Vocus chemical ionization time-of-flight mass spectrometer with ammonium (NH₄ ⁺) as the reagent ion operating at 1 Hz. The range of observations spanned volatile, intermediate-volatility, and semi-volatile organic compounds with targeted analyses of ~150 ions whose likely assignments included a range of functionalized compound classes such as glycols, glycol ethers, acetates, acids, alcohols, acrylates, esters, ethanolamines, and ketones that are found in various consumer, commercial, and industrial products. Their concentrations varied as a function of wind direction with enhancements over the highly-populated areas of the Bronx, Manhattan, and parts of New Jersey, and included abundant concentrations of acetates, acrylates, ethylene glycol, and other commonly-used oxygenated compounds. The results provide top-down constraints on wintertime emissions of these oxygenated/functionalized compounds with ratios to common anthropogenic marker compounds, and comparisons of their relative abundances to two regionally-resolved emissions inventories used in urban air quality models.</p>","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"22 21","pages":"14377-14399"},"PeriodicalIF":6.3,"publicationDate":"2022-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9728622/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10366315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The pathway of impacts of aerosol direct effects on secondary inorganic aerosol formation.","authors":"Jiandong Wang, Jia Xing, Shuxiao Wang, Rohit Mathur, Jiaping Wang, Yuqiang Zhang, Chao Liu, Jonathan Pleim, Dian Ding, Xing Chang, Jingkun Jiang, Peng Zhao, Shovan Kumar Sahu, Yuzhi Jin, David C Wong, Jiming Hao","doi":"10.5194/acp-22-5147-2022","DOIUrl":"10.5194/acp-22-5147-2022","url":null,"abstract":"<p><p>Airborne aerosols reduce surface solar radiation through light scattering and absorption (aerosol direct effects, ADEs), influence regional meteorology, and further affect atmospheric chemical reactions and aerosol concentrations. The inhibition of turbulence and the strengthened atmospheric stability induced by ADEs increases surface primary aerosol concentration, but the pathway of ADE impacts on secondary aerosol is still unclear. In this study, the online coupled meteorological and chemistry model (WRF-CMAQ; Weather Research and Forecasting-Community Multiscale Air Quality) with integrated process analysis was applied to explore how ADEs affect secondary aerosol formation through changes in atmospheric dynamics and photolysis processes. The meteorological condition and air quality in the Jing-Jin-Ji area (denoted JJJ, including Beijing, Tianjin, and Hebei Province in China) in January and July 2013 were simulated to represent winter and summer conditions, respectively. Our results show that ADEs through the photolysis pathway inhibit sulfate formation during winter in the JJJ region and promote sulfate formation in July. The differences are attributed to the alteration of effective actinic flux affected by single-scattering albedo (SSA). ADEs through the dynamics pathway act as an equally or even more important route compared with the photolysis pathway in affecting secondary aerosol concentration in both summer and winter. ADEs through dynamics traps formed sulfate within the planetary boundary layer (PBL) which increases sulfate concentration in winter. Meanwhile, the impact of ADEs through dynamics is mainly reflected in the increase of gaseous-precursor concentrations within the PBL which enhances secondary aerosol formation in summer. For nitrate, reduced upward transport of precursors restrains the formation at high altitude and eventually lowers the nitrate concentration within the PBL in winter, while such weakened vertical transport of precursors increases nitrate concentration within the PBL in summer, since nitrate is mainly formed near the surface ground.</p>","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"22 8","pages":"5147-5156"},"PeriodicalIF":5.2,"publicationDate":"2022-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9413026/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9327957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atmospheric biogenic volatile organic compounds in the Alaskan Arctic tundra: constraints from measurements at Toolik Field Station.","authors":"Vanessa Selimovic,&nbsp;Damien Ketcherside,&nbsp;Sreelekha Chaliyakunnel,&nbsp;Catherine Wielgasz,&nbsp;Wade Permar,&nbsp;Hélène Angot,&nbsp;Dylan B Millet,&nbsp;Alan Fried,&nbsp;Detlev Helmig,&nbsp;Lu Hu","doi":"10.5194/acp-22-14037-2022","DOIUrl":"https://doi.org/10.5194/acp-22-14037-2022","url":null,"abstract":"<p><p>The Arctic is a climatically sensitive region that has experienced warming at almost 3 times the global average rate in recent decades, leading to an increase in Arctic greenness and a greater abundance of plants that emit biogenic volatile organic compounds (BVOCs). These changes in atmospheric emissions are expected to significantly modify the overall oxidative chemistry of the region and lead to changes in VOC composition and abundance, with implications for atmospheric processes. Nonetheless, observations needed to constrain our current understanding of these issues in this critical environment are sparse. This work presents novel atmospheric in situ proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) measurements of VOCs at Toolik Field Station (TFS; 68°38' N, 149°36' W), in the Alaskan Arctic tundra during May-June 2019. We employ a custom nested grid version of the GEOS-Chem chemical transport model (CTM), driven with MEGANv2.1 (Model of Emissions of Gases and Aerosols from Nature version 2.1) biogenic emissions for Alaska at 0.25° × 0.3125° resolution, to interpret the observations in terms of their constraints on BVOC emissions, total reactive organic carbon (ROC) composition, and calculated OH reactivity (OHr) in this environment. We find total ambient mole fraction of 78 identified VOCs to be 6.3 ± 0.4 ppbv (10.8 ± 0.5 ppbC), with overwhelming (> 80 %) contributions are from short-chain oxygenated VOCs (OVOCs) including methanol, acetone and formaldehyde. Isoprene was the most abundant terpene identified. GEOS-Chem captures the observed isoprene (and its oxidation products), acetone and acetaldehyde abundances within the combined model and observation uncertainties (±25 %), but underestimates other OVOCs including methanol, formaldehyde, formic acid and acetic acid by a factor of 3 to 12. The negative model bias for methanol is attributed to underestimated biogenic methanol emissions for the Alaskan tundra in MEGANv2.1. Observed formaldehyde mole fractions increase exponentially with air temperature, likely reflecting its biogenic precursors and pointing to a systematic model underprediction of its secondary production. The median campaign-calculated OHr from VOCs measured at TFS was 0.7 s^-1, roughly 5 % of the values typically reported in lower-latitude forested ecosystems. Ten species account for over 80 % of the calculated VOC OHr, with formaldehyde, isoprene and acetaldehyde together accounting for nearly half of the total. Simulated OHr based on median-modeled VOCs included in GEOS-Chem averages 0.5 s^-1 and is dominated by isoprene (30 %) and monoterpenes (17 %). The data presented here serve as a critical evaluation of our knowledge of BVOCs and ROC budgets in high-latitude environments and represent a foundation for investigating and interpreting future warming-driven changes in VOC emissions in the Alaskan Arctic tundra.</p>","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"22 21","pages":"14037-14058"},"PeriodicalIF":6.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10358744/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9855106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical and machine learning methods for evaluating trends in air quality under changing meteorological conditions.","authors":"Minghao Qiu, Corwin Zigler, Noelle E Selin","doi":"10.5194/acp-22-10551-2022","DOIUrl":"10.5194/acp-22-10551-2022","url":null,"abstract":"<p><p>Evaluating the influence of anthropogenic-emission changes on air quality requires accounting for the influence of meteorological variability. Statistical methods such as multiple linear regression (MLR) models with basic meteorological variables are often used to remove meteorological variability and estimate trends in measured pollutant concentrations attributable to emission changes. However, the ability of these widely used statistical approaches to correct for meteorological variability remains unknown, limiting their usefulness in the real-world policy evaluations. Here, we quantify the performance of MLR and other quantitative methods using simulations from a chemical transport model, GEOS-Chem, as a synthetic dataset. Focusing on the impacts of anthropogenic-emission changes in the US (2011 to 2017) and China (2013 to 2017) on PM_2.5 and O₃, we show that widely used regression methods do not perform well in correcting for meteorological variability and identifying long-term trends in ambient pollution related to changes in emissions. The estimation errors, characterized as the differences between meteorology-corrected trends and emission-driven trends under constant meteorology scenarios, can be reduced by 30%-42% using a random forest model that incorporates both local- and regional-scale meteorological features. We further design a correction method based on GEOS-Chem simulations with constant-emission input and quantify the degree to which anthropogenic emissions and meteorological influences are inseparable, due to their process-based interactions. We conclude by providing recommendations for evaluating the impacts of anthropogenic-emission changes on air quality using statistical approaches.</p>","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"22 16","pages":"10551-10566"},"PeriodicalIF":5.2,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9957566/pdf/nihms-1831220.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9407480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling pathways of elevated ozone induced by the 2020 lockdown in Europe by an observationally constrained regional model using TROPOMI.","authors":"Amir H Souri,&nbsp;Kelly Chance,&nbsp;Juseon Bak,&nbsp;Caroline R Nowlan,&nbsp;Gonzalo González Abad,&nbsp;Yeonjin Jung,&nbsp;David C Wong,&nbsp;Jingqiu Mao,&nbsp;Xiong Liu","doi":"10.5194/acp-21-18227-2021","DOIUrl":"https://doi.org/10.5194/acp-21-18227-2021","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Questions about how emissions are changing during the COVID-19 lockdown periods cannot be answered by observations of atmospheric trace gas concentrations alone, in part due to simultaneous changes in atmospheric transport, emissions, dynamics, photochemistry, and chemical feedback. A chemical transport model simulation benefiting from a multi-species inversion framework using well-characterized observations should differentiate those influences enabling to closely examine changes in emissions. Accordingly, we jointly constrain NO &lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; and VOC emissions using well-characterized TROPOspheric Monitoring Instrument (TROPOMI) HCHO and NO&lt;sub&gt;2&lt;/sub&gt; columns during the months of March, April, and May 2020 (lockdown) and 2019 (baseline). We observe a noticeable decline in the magnitude of NO &lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; emissions in March 2020 (14 %-31 %) in several major cities including Paris, London, Madrid, and Milan, expanding further to Rome, Brussels, Frankfurt, Warsaw, Belgrade, Kyiv, and Moscow (34 %-51 %) in April. However, NO &lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt; emissions remain at somewhat similar values or even higher in some portions of the UK, Poland, and Moscow in March 2020 compared to the baseline, possibly due to the timeline of restrictions. Comparisons against surface monitoring stations indicate that the constrained model underrepresents the reduction in surface NO&lt;sub&gt;2&lt;/sub&gt;. This underrepresentation correlates with the TROPOMI frequency impacted by cloudiness. During the month of April, when ample TROPOMI samples are present, the surface NO&lt;sub&gt;2&lt;/sub&gt; reductions occurring in polluted areas are described fairly well by the model (model: -21 ± 17 %, observation: -29 ± 21 %). The observational constraint on VOC emissions is found to be generally weak except for lower latitudes. Results support an increase in surface ozone during the lockdown. In April, the constrained model features a reasonable agreement with maximum daily 8 h average (MDA8) ozone changes observed at the surface (&lt;i&gt;r&lt;/i&gt; = 0.43), specifically over central Europe where ozone enhancements prevail (model: +3.73 ± 3.94 %, + 1.79 ppbv, observation: +7.35 ± 11.27 %, +3.76 ppbv). The model suggests that physical processes (dry deposition, advection, and diffusion) decrease MDA8 surface ozone in the same month on average by -4.83 ppbv, while ozone production rates dampened by largely negative &lt;math&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;J&lt;/mi&gt; &lt;mrow&gt; &lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;NO&lt;/mtext&gt;&lt;/mrow&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt; &lt;/mrow&gt; &lt;/msub&gt; &lt;mrow&gt;&lt;mo&gt;[&lt;/mo&gt; &lt;mrow&gt; &lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;NO&lt;/mtext&gt;&lt;/mrow&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt; &lt;/mrow&gt; &lt;mo&gt;]&lt;/mo&gt;&lt;/mrow&gt; &lt;mo&gt;-&lt;/mo&gt; &lt;msub&gt;&lt;mi&gt;k&lt;/mi&gt; &lt;mrow&gt;&lt;mtext&gt;NO&lt;/mtext&gt; &lt;mo&gt;+&lt;/mo&gt; &lt;msub&gt;&lt;mtext&gt;O&lt;/mtext&gt; &lt;mn&gt;3&lt;/mn&gt;&lt;/msub&gt; &lt;/mrow&gt; &lt;/msub&gt; &lt;mo&gt;[&lt;/mo&gt; &lt;mtext&gt;NO&lt;/mtext&gt; &lt;mo&gt;]&lt;/mo&gt; &lt;mrow&gt;&lt;mo&gt;[&lt;/mo&gt; &lt;mrow&gt;&lt;msub&gt;&lt;mtext&gt;O&lt;/mtext&gt; &lt;mn&gt;3&lt;/mn&gt;&lt;/msub&gt; &lt;/mrow&gt; &lt;mo&gt;]&lt;/mo&gt;&lt;/mrow&gt; &lt;/mrow&gt; &lt;/math&gt; become less negative, leading ozone to increase by +5.89 ppbv. Experiments involving fixed anthropogenic emission","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"21 ","pages":"1-19"},"PeriodicalIF":6.3,"publicationDate":"2021-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8721815/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10358724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved representation of the global dust cycle using observational constraints on dust properties and abundance.","authors":"Jasper F Kok,&nbsp;Adeyemi A Adebiyi,&nbsp;Samuel Albani,&nbsp;Yves Balkanski,&nbsp;Ramiro Checa-Garcia,&nbsp;Mian Chin,&nbsp;Peter R Colarco,&nbsp;Douglas S Hamilton,&nbsp;Yue Huang,&nbsp;Akinori Ito,&nbsp;Martina Klose,&nbsp;Danny M Leung,&nbsp;Longlei Li,&nbsp;Natalie M Mahowald,&nbsp;Ron L Miller,&nbsp;Vincenzo Obiso,&nbsp;Carlos Pérez García-Pando,&nbsp;Adriana Rocha-Lima,&nbsp;Jessica S Wan,&nbsp;Chloe A Whicker","doi":"10.5194/acp-21-8127-2021","DOIUrl":"https://doi.org/10.5194/acp-21-8127-2021","url":null,"abstract":"<p><p>Even though desert dust is the most abundant aerosol by mass in Earth's atmosphere, atmospheric models struggle to accurately represent its spatial and temporal distribution. These model errors are partially caused by fundamental difficulties in simulating dust emission in coarse-resolution models and in accurately representing dust microphysical properties. Here we mitigate these problems by developing a new methodology that yields an improved representation of the global dust cycle. We present an analytical framework that uses inverse modeling to integrate an ensemble of global model simulations with observational constraints on the dust size distribution, extinction efficiency, and regional dust aerosol optical depth. We then compare the inverse model results against independent measurements of dust surface concentration and deposition flux and find that errors are reduced by approximately a factor of two relative to current model simulations of the Northern Hemisphere dust cycle. The inverse model results show smaller improvements in the less dusty Southern Hemisphere, most likely because both the model simulations and the observational constraints used in the inverse model are less accurate. On a global basis, we find that the emission flux of dust with geometric diameter up to 20 μm (PM₂₀) is approximately 5,000 Tg/year, which is greater than most models account for. This larger PM₂₀ dust flux is needed to match observational constraints showing a large atmospheric loading of coarse dust. We obtain gridded data sets of dust emission, vertically integrated loading, dust aerosol optical depth, (surface) concentration, and wet and dry deposition fluxes that are resolved by season and particle size. As our results indicate that this data set is more accurate than current model simulations and the MERRA-2 dust reanalysis product, it can be used to improve quantifications of dust impacts on the Earth system.</p>","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"21 10","pages":"8127-8167"},"PeriodicalIF":6.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10466066/pdf/nihms-1863803.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10509952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Background conditions for an urban greenhouse gas network in the Washington, D.C. and Baltimore metropolitan region.","authors":"Anna Karion,&nbsp;Israel Lopez-Coto,&nbsp;Sharon M Gourdji,&nbsp;Kimberly Mueller,&nbsp;Subhomoy Ghosh,&nbsp;William Callahan,&nbsp;Michael Stock,&nbsp;Elizabeth DiGangi,&nbsp;Steve Prinzivalli,&nbsp;James Whetstone","doi":"10.5194/acp-21-6257-2021","DOIUrl":"https://doi.org/10.5194/acp-21-6257-2021","url":null,"abstract":"<p><p>As city governments take steps towards establishing emissions reduction targets, the atmospheric research community is increasingly able to assist in tracking emissions reductions. Researchers have established systems for observing atmospheric greenhouse gases in urban areas with the aim of attributing greenhouse gas concentration enhancements (and thus, emissions) to the region in question. However, to attribute enhancements to a particular region, one must isolate the component of the observed concentration attributable to fluxes inside the region by removing the background, which is the component due to fluxes outside. In this study, we demonstrate methods to construct several versions of a background for our carbon dioxide and methane observing network in the Washington, DC and Baltimore, MD metropolitan region. Some of these versions rely on transport and flux models, while others are based on observations upwind of the domain. First, we evaluate the backgrounds in a synthetic data framework, then we evaluate against real observations from our urban network. We find that backgrounds based on upwind observations capture the variability better than model-based backgrounds, although care must be taken to avoid bias from biospheric carbon dioxide fluxes near background stations in summer. Model-based backgrounds also perform well when upwind fluxes can be modeled accurately. Our study evaluates different background methods and provides guidance determining background methodology that can impact the design of urban monitoring networks.</p>","PeriodicalId":8611,"journal":{"name":"Atmospheric Chemistry and Physics","volume":"21 8","pages":""},"PeriodicalIF":6.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9982866/pdf/nihms-1873186.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9080828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}