Articles | Volume 22, issue 17
05 Sep 2022
Research article | 05 Sep 2022
The positive effect of formaldehyde on the photocatalytic renoxification of nitrate on TiO2 particles
Yuhan Liu et al.
No articles found.
Hao Yin, Youwen Sun, Justus Notholt, Mathias Palm, Chunxiang Ye, and Cheng Liu
Atmos. Chem. Phys., 22, 14401–14419,Short summary
Improved knowledge of the chemistry and drivers of surface ozone over the Qinghai-Tibet Plateau (QTP) is significant for regulatory and control purposes in this high-altitude region in the Himalayas. Our study investigates the processes and drivers of surface ozone anomalies by using machine-learning model-based meteorological normalization methods between 2015 and 2020 in urban areas over the QTP. This study can provide valuable implication for ozone mitigation over the QTP.
Lizi Tang, Min Hu, Dongjie Shang, Xin Fang, Janjiong Mao, Wanyun Xu, Jiacheng Zhou, Weixiong Zhao, Yaru Wang, Chong Zhang, Yingjie Zhang, Jianlin Hu, Limin Zeng, Chunxiang Ye, Song Guo, and Zhijun Wu
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
There was an evident distinction in the frequencies of NPF events at Nam Co station in the Tibetan Plateau with 15 % in pre-monsoon season and 80 % in monsoon season. The frequent NPF events in monsoon season resulted from the higher concentration of organic vapours, which was brought from northeast India by the strong southerly monsoon. It had increased significantly the amount of aerosol and CCN compared with those in pre-monsoon season, which may markedly affect the earth's radiation balance.
Marios Panagi, Roberto Sommariva, Zoë L. Fleming, Paul S. Monks, Gongda Lu, Eloise A. Marais, James R. Hopkins, Alastair C. Lewis, Qiang Zhang, James D. Lee, Freya A. Squires, Lisa K. Whalley, Eloise J. Slater, Dwayne E. Heard, Robert Woodward-Massey, Chunxiang Ye, and Joshua D. Vande Hey
Atmos. Chem. Phys. Discuss.,
Preprint under review for ACPShort summary
A dispersion model and a box model were combined to investigate the evolution of VOCs in Beijing once they are emitted from anthropogenic sources. It was determined that during the winter time the VOC concentrations in Beijing are driven predominantly by sources within Beijing and by a combination of transport and chemistry during the summer. Furthermore, the results in the paper highlight the need for a season specific policy.
Yuting Zhu, Youfeng Wang, Xianliang Zhou, Yasin F. Elshorbany, Chunxiang Ye, Matthew Hayden, and Andrew J. Peters
Atmos. Chem. Phys., 22, 6327–6346,Short summary
The daytime chemistry of nitrous acid (HONO), which plays an important role in the oxidation capacity of the troposphere, is not well understood. In this work, we report new field measurement results of HONO and the relevant parameters in the marine boundary layer at Tudor Hill Marine Atmospheric Observatory in Bermuda. We evaluate the daytime HONO budgets in air masses under different types of interaction with the island and examine the strengths of different HONO formation and loss mechanisms.
Claire E. Reeves, Graham P. Mills, Lisa K. Whalley, W. Joe F. Acton, William J. Bloss, Leigh R. Crilley, Sue Grimmond, Dwayne E. Heard, C. Nicholas Hewitt, James R. Hopkins, Simone Kotthaus, Louisa J. Kramer, Roderic L. Jones, James D. Lee, Yanhui Liu, Bin Ouyang, Eloise Slater, Freya Squires, Xinming Wang, Robert Woodward-Massey, and Chunxiang Ye
Atmos. Chem. Phys., 21, 6315–6330,Short summary
The impact of isoprene on atmospheric chemistry is dependent on how its oxidation products interact with other pollutants, specifically nitrogen oxides. Such interactions can lead to isoprene nitrates. We made measurements of the concentrations of individual isoprene nitrate isomers in Beijing and used a model to test current understanding of their chemistry. We highlight areas of uncertainty in understanding, in particular the chemistry following oxidation of isoprene by the nitrate radical.
Weili Lin, Feng Wang, Chunxiang Ye, and Tong Zhu
The Cryosphere Discuss.,
Preprint withdrawnShort summary
Field observations found that released NOx on the glacier surface of the Tibetan Plateau, an important snow-covered region in the northern mid-latitudes, had a higher concentration than in Antarctic and Arctic regions. Such evidence, and such high fluxes as observed here on the Tibetan plateau is novel. That such high concentrations of nitrogen oxides can be found in remote areas is interesting and important for the oxidative budget of the boundary layer.
Lisa K. Whalley, Eloise J. Slater, Robert Woodward-Massey, Chunxiang Ye, James D. Lee, Freya Squires, James R. Hopkins, Rachel E. Dunmore, Marvin Shaw, Jacqueline F. Hamilton, Alastair C. Lewis, Archit Mehra, Stephen D. Worrall, Asan Bacak, Thomas J. Bannan, Hugh Coe, Carl J. Percival, Bin Ouyang, Roderic L. Jones, Leigh R. Crilley, Louisa J. Kramer, William J. Bloss, Tuan Vu, Simone Kotthaus, Sue Grimmond, Yele Sun, Weiqi Xu, Siyao Yue, Lujie Ren, W. Joe F. Acton, C. Nicholas Hewitt, Xinming Wang, Pingqing Fu, and Dwayne E. Heard
Atmos. Chem. Phys., 21, 2125–2147,Short summary
To understand how emission controls will impact ozone, an understanding of the sources and sinks of OH and the chemical cycling between peroxy radicals is needed. This paper presents measurements of OH, HO2 and total RO2 taken in central Beijing. The radical observations are compared to a detailed chemistry model, which shows that under low NO conditions, there is a missing OH source. Under high NOx conditions, the model under-predicts RO2 and impacts our ability to model ozone.
Mike J. Newland, Daniel J. Bryant, Rachel E. Dunmore, Thomas J. Bannan, W. Joe F. Acton, Ben Langford, James R. Hopkins, Freya A. Squires, William Dixon, William S. Drysdale, Peter D. Ivatt, Mathew J. Evans, Peter M. Edwards, Lisa K. Whalley, Dwayne E. Heard, Eloise J. Slater, Robert Woodward-Massey, Chunxiang Ye, Archit Mehra, Stephen D. Worrall, Asan Bacak, Hugh Coe, Carl J. Percival, C. Nicholas Hewitt, James D. Lee, Tianqu Cui, Jason D. Surratt, Xinming Wang, Alastair C. Lewis, Andrew R. Rickard, and Jacqueline F. Hamilton
Atmos. Chem. Phys., 21, 1613–1625,Short summary
We report the formation of secondary pollutants in the urban megacity of Beijing that are typically associated with remote regions such as rainforests. This is caused by extremely low levels of nitric oxide (NO), typically expected to be high in urban areas, observed in the afternoon. This work has significant implications for how we understand atmospheric chemistry in the urban environment and thus for how to implement effective policies to improve urban air quality.
Eloise J. Slater, Lisa K. Whalley, Robert Woodward-Massey, Chunxiang Ye, James D. Lee, Freya Squires, James R. Hopkins, Rachel E. Dunmore, Marvin Shaw, Jacqueline F. Hamilton, Alastair C. Lewis, Leigh R. Crilley, Louisa Kramer, William Bloss, Tuan Vu, Yele Sun, Weiqi Xu, Siyao Yue, Lujie Ren, W. Joe F. Acton, C. Nicholas Hewitt, Xinming Wang, Pingqing Fu, and Dwayne E. Heard
Atmos. Chem. Phys., 20, 14847–14871,Short summary
The paper details atmospheric chemistry in a megacity (Beijing), focussing on radicals which mediate the formation of secondary pollutants such as ozone and particles. Highly polluted conditions were experienced, including the highest ever levels of nitric oxide (NO), with simultaneous radical measurements. Radical concentrations were large during "haze" events, demonstrating active photochemistry. Modelling showed that our understanding of the chemistry at high NOx levels is incomplete.
Robert Woodward-Massey, Eloise J. Slater, Jake Alen, Trevor Ingham, Danny R. Cryer, Leanne M. Stimpson, Chunxiang Ye, Paul W. Seakins, Lisa K. Whalley, and Dwayne E. Heard
Atmos. Meas. Tech., 13, 3119–3146,Short summary
The OH radical is known as nature’s detergent, removing most trace gases from the atmosphere. Hence, an accurate measurement of its concentration is very important. We present measurements of OH in several field locations using a laser-based fluorescence method equipped with an OH scavenger. By determining the background signal in two different ways, we show that the instrument does not suffer any significant interferences that could result in an overestimation of OH concentrations.
Fanhao Meng, Min Qin, Ke Tang, Jun Duan, Wu Fang, Shuaixi Liang, Kaidi Ye, Pinhua Xie, Yele Sun, Conghui Xie, Chunxiang Ye, Pingqing Fu, Jianguo Liu, and Wenqing Liu
Atmos. Chem. Phys., 20, 5071–5092,Short summary
Nitrous acid (HONO), a major precursor of the OH radical, plays a key role in atmospheric chemistry, but its sources are still debated. The first high-resolution vertical measurements of HONO and NO2 were conducted in Beijing to investigate the nocturnal sources of HONO at different stages of pollution. The ground surface dominated HONO production by heterogeneous conversion of NO2 during clean episodes, but the aerosol production was an important nighttime HONO source during haze episodes.
Yingruo Li, Ziqiang Tan, Chunxiang Ye, Junxia Wang, Yanwen Wang, Yi Zhu, Pengfei Liang, Xi Chen, Yanhua Fang, Yiqun Han, Qi Wang, Di He, Yao Wang, and Tong Zhu
Atmos. Chem. Phys., 19, 13841–13857,Short summary
Vehicle emissions are a major source of Beijing's pollution. Various vehicle emission control policies have been implemented at great cost, but there is a lack of appropriate methods to evaluate the effectiveness of such policies. Here we developed a new method to evaluate the effectiveness of vehicle emission control policies during APEC. Our findings are instructive for air pollution control policy making.
Yanhua Fang, Chunxiang Ye, Junxia Wang, Yusheng Wu, Min Hu, Weili Lin, Fanfan Xu, and Tong Zhu
Atmos. Chem. Phys., 19, 12295–12307,Short summary
Year-long observations of PM2.5, gaseous pollutants, and meteorological parameters in Beijing were analysed to investigate sulfate formation. RH and O3 concentrations above thresholds of 45 % and 35 ppb, respectively, greatly accelerated sulfate formation. Ambient changes in RH and O3 contributed to variations in sulfate formation among different seasons and pollution levels. A shift from gas-phase to multiphase SO2 oxidation contributed to fast sulfate formation under polluted conditions.
Chunxiang Ye, Xianliang Zhou, Dennis Pu, Jochen Stutz, James Festa, Max Spolaor, Catalina Tsai, Christopher Cantrell, Roy L. Mauldin III, Andrew Weinheimer, Rebecca S. Hornbrook, Eric C. Apel, Alex Guenther, Lisa Kaser, Bin Yuan, Thomas Karl, Julie Haggerty, Samuel Hall, Kirk Ullmann, James Smith, and John Ortega
Atmos. Chem. Phys., 18, 9107–9120,Short summary
Substantial levels of HONO existed during the day throughout the troposphere over the southeastern US during NOMADSS 2013. Particulate nitrate photolysis appeared to be the major volume HONO source, while NOx was an important HONO precursor only in industrial and urban plumes. HONO was not a significant OH radical precursor in the rural troposphere away from the ground surface; however, its production from particulate nitrate photolysis was an important renoxification pathway.
Defeng Zhao, Xiaojuan Song, Tong Zhu, Zefeng Zhang, Yingjun Liu, and Jing Shang
Atmos. Chem. Phys., 18, 2481–2493,Short summary
The oxidation of SO2 directly by NO2 on solid/liquid particles is proposed to be a major pathway of particle sulfate formation in the polluted atmosphere. We found that the reaction of SO2 and NO2 on CaCO3 particles produced Ca(NO3)2 aqueous droplets, providing a site for the multiphase oxidation of SO2. The direct multiphase oxidation of SO2 by NO2 led to a reactive uptake coefficient of SO2 on the order of 10-8, which is unlikely to be an important source of sulfate in the ambient atmosphere.
Related subject area
Subject: Aerosols | Research Activity: Laboratory Studies | Altitude Range: Troposphere | Science Focus: Chemistry (chemical composition and reactions)Chamber investigation of the formation and transformation of secondary organic aerosol in mixtures of biogenic and anthropogenic volatile organic compoundsNot all types of secondary organic aerosol mix: two phases observed when mixing different secondary organic aerosol typesComprehensive characterization of particulate intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from heavy-duty diesel vehicles using two-dimensional gas chromatography time-of-flight mass spectrometryMeasurement report: Investigation of pH- and particle-size-dependent chemical and optical properties of water-soluble organic carbon: implications for its sources and aging processesThe influence of the addition of isoprene on the volatility of particles formed from the photo-oxidation of anthropogenic–biogenic mixturesSignificant formation of sulfate aerosols contributed by the heterogeneous drivers of dust surfaceParticle-phase processing of α-pinene NO3 secondary organic aerosol in the darkChemical characteristics and sources of PM2.5 in Hohhot, a semi-arid city in northern China: insight from the COVID-19 lockdownWinter brown carbon over six China’s megacities: Light absorption, molecular characterization, and improved source apportionment revealed by multilayer perceptron neural networkIdentification of highly oxygenated organic molecules and their role in aerosol formation in the reaction of limonene with nitrate radicalA comprehensive study on hygroscopic behaviour and nitrate depletion of NaNO3 and dicarboxylic acid mixtures: implications for nitrate depletion in tropospheric aerosolsSecondary organic aerosols from OH oxidation of cyclic volatile methyl siloxanes as an important Si source in the atmosphereEffects of OH radical and SO2 concentrations on photochemical reactions of mixed anthropogenic organic gasesEffects of the sample matrix on the photobleaching and photodegradation of toluene-derived secondary organic aerosol compoundsFunctionality-based formation of secondary organic aerosol from m-xylene photooxidationChemical composition of secondary organic aerosol particles formed from mixtures of anthropogenic and biogenic precursorsThe Urmia Playa as source of airborne dust and ice nucleating particles – Part 2: Unraveling the relationship between soil dust composition and ice-nucleation activityA novel pathway of atmospheric sulfate formation through carbonate radicalsA sulfuric acid nucleation potential model for the atmosphereOptical and chemical properties and oxidative potential of aqueous-phase products from OH and 3C∗-initiated photooxidation of eugenolThe relationship between PM2.5 and anticyclonic wave activity during summer over the United StatesIron from coal combustion particles dissolves much faster than mineral dust under simulated atmospheric acidic conditionsCellulose in atmospheric particulate matter at rural and urban sites across France and SwitzerlandKinetics, SOA yields, and chemical composition of secondary organic aerosol from β-caryophyllene ozonolysis with and without nitrogen oxides between 213 and 313 KChemical transformation of α-pinene-derived organosulfate via heterogeneous OH oxidation: implications for sources and environmental fates of atmospheric organosulfatesAqueous chemical bleaching of 4-nitrophenol brown carbon by hydroxyl radicals; products, mechanism, and light absorptionSecondary organic aerosol formation from camphene oxidation: measurements and modelingTechnical note: Real-time diagnosis of the hygroscopic growth micro-dynamics of nanoparticles with Fourier transform infrared spectroscopySingle-particle Raman spectroscopy for studying physical and chemical processes of atmospheric particlesAre reactive oxygen species (ROS) a suitable metric to predict toxicity of carbonaceous aerosol particles?Secondary organic aerosol and organic nitrogen yields from the nitrate radical (NO3) oxidation of alpha-pinene from various RO2 fatesSecondary organic aerosol formation from the oxidation of decamethylcyclopentasiloxane at atmospherically relevant OH concentrationsAqueous secondary organic aerosol formation from the direct photosensitized oxidation of vanillin in the absence and presence of ammonium nitrateEvolution of volatility and composition in sesquiterpene-mixed and α-pinene secondary organic aerosol particles during isothermal evaporationPotential new tracers and their mass fraction in the emitted PM10 from the burning of household waste in stovesSynergetic effects of NH3 and NOx on the production and optical absorption of secondary organic aerosol formation from toluene photooxidationChemical composition of nanoparticles from α-pinene nucleation and the influence of isoprene and relative humidity at low temperatureTechnical note: Adsorption and desorption equilibria from statistical thermodynamics and rates from transition state theoryNighttime chemistry of biomass burning emissions in urban areas: A dual mobile chamber studyFormation and evolution of secondary organic aerosols derived from urban-lifestyle sources: vehicle exhaust and cooking emissionsMass spectral characterization of secondary organic aerosol from urban cooking and vehicular sourcesAn organic crystalline state in ageing atmospheric aerosol proxies: spatially resolved structural changes in levitated fatty acid particlesPhotolytically induced changes in composition and volatility of biogenic secondary organic aerosol from nitrate radical oxidation during night-to-day transitionThe driving factors of new particle formation and growth in the polluted boundary layerExploring the composition and volatility of secondary organic aerosols in mixed anthropogenic and biogenic precursor systemsAcidity and the multiphase chemistry of atmospheric aqueous particles and cloudsChemical composition, optical properties, and oxidative potential of water- and methanol-soluble organic compounds emitted from the combustion of biomass materials and coalPhotodegradation of atmospheric chromophores: changes in oxidation state and photochemical reactivityTemperature and volatile organic compound concentrations as controlling factors for chemical composition of α-pinene-derived secondary organic aerosolTracer-based source apportioning of atmospheric organic carbon and the influence of anthropogenic emissions on secondary organic aerosol formation in Hong Kong
Aristeidis Voliotis, Mao Du, Yu Wang, Yunqi Shao, M. Rami Alfarra, Thomas J. Bannan, Dawei Hu, Kelly L. Pereira, Jaqueline F. Hamilton, Mattias Hallquist, Thomas F. Mentel, and Gordon McFiggans
Atmos. Chem. Phys., 22, 14147–14175,Short summary
Mixing experiments are crucial and highly beneficial for our understanding of atmospheric chemical interactions. However, interpretation quickly becomes complex, and both the experimental design and evaluation need to be scrutinised carefully. Advanced online and offline compositional measurements can reveal substantial additional information to aid in the interpretation of yield data, including components uniquely found in mixtures and property changes in SOA formed from mixtures of VOCs.
Fabian Mahrt, Long Peng, Julia Zaks, Yuanzhou Huang, Paul E. Ohno, Natalie R. Smith, Florence K. A. Gregson, Yiming Qin, Celia L. Faiola, Scot T. Martin, Sergey A. Nizkorodov, Markus Ammann, and Allan K. Bertram
Atmos. Chem. Phys., 22, 13783–13796,Short summary
The number of condensed phases in mixtures of different secondary organic aerosol (SOA) types determines their impact on air quality and climate. Here we observe the number of phases in individual particles that contain mixtures of two different types of SOA. We find that SOA mixtures can form one- or two-phase particles, depending on the difference in the average oxygen-to-carbon (O / C) ratios of the two SOA types that are internally mixed within individual particles.
Xiao He, Xuan Zheng, Shaojun Zhang, Xuan Wang, Ting Chen, Xiao Zhang, Guanghan Huang, Yihuan Cao, Liqiang He, Xubing Cao, Yuan Cheng, Shuxiao Wang, and Ye Wu
Atmos. Chem. Phys., 22, 13935–13947,Short summary
With the use of two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC ToF-MS), we successfully give a comprehensive characterization of particulate intermediate-volatility and semi-volatile organic compounds (I/SVOCs) emitted from heavy-duty diesel vehicles. I/SVOCs are speciated, identified, and quantified based on the patterns of the mass spectrum, and the gas–particle partitioning is fully addressed.
Yuanyuan Qin, Juanjuan Qin, Xiaobo Wang, Kang Xiao, Ting Qi, Yuwei Gao, Xueming Zhou, Shaoxuan Shi, Jingnan Li, Jingsi Gao, Ziyin Zhang, Jihua Tan, Yang Zhang, and Rongzhi Chen
Atmos. Chem. Phys., 22, 13845–13859,Short summary
Deep interrogation of water-soluble organic carbon (WSOC) in aerosols is critical and challenging considering its involvement in many key aerosol-associated chemical reactions. This work examined how the chemical structures (functional groups) and optical properties (UV/fluorescence properties) of WSOC were affected by pH and particle size. We found that the pH- and particle-size-dependent behaviors could be used to reveal the structures, sources, and aging of aerosol WSOC.
Aristeidis Voliotis, Mao Du, Yu Wang, Yunqi Shao, Thomas J. Bannan, Michael Flynn, Spyros N. Pandis, Carl J. Percival, M. Rami Alfarra, and Gordon McFiggans
Atmos. Chem. Phys., 22, 13677–13693,Short summary
The addition of a low-yield precursor to the reactive mixture of aVOC and bVOC can increase or decrease the SOA volatility that is system-dependent. Therefore, the SOA volatility of the mixtures cannot always be predicted based on the additivity. In complex mixtures the formation of lower-volatility products likely outweighs the formation of products with higher volatility. The unique products of each mixture contribute significantly to the signal, suggesting interactions can be important.
Tao Wang, Yangyang Liu, Hanyun Cheng, Zhenzhen Wang, Hongbo Fu, Jianmin Chen, and Liwu Zhang
Atmos. Chem. Phys., 22, 13467–13493,Short summary
This study compared the gas-phase, aqueous-phase, and heterogeneous SO2 oxidation pathways by combining laboratory work with a modelling study. The heterogeneous oxidation, particularly that induced by the dust surface drivers, presents positive implications for the removal of airborne SO2 and formation of sulfate aerosols. This work highlighted the atmospheric significance of heterogeneous oxidation and suggested a comparison model to evaluate the following heterogeneous laboratory research.
David M. Bell, Cheng Wu, Amelie Bertrand, Emelie Graham, Janne Schoonbaert, Stamatios Giannoukos, Urs Baltensperger, Andre S. H. Prevot, Ilona Riipinen, Imad El Haddad, and Claudia Mohr
Atmos. Chem. Phys., 22, 13167–13182,Short summary
A series of studies designed to investigate the evolution of organic aerosol were performed in an atmospheric simulation chamber, using a common oxidant found at night (NO3). The chemical composition steadily changed from its initial composition via different chemical reactions that were taking place inside of the aerosol particle. These results show that the composition of organic aerosol steadily changes during its lifetime in the atmosphere.
Haijun Zhou, Tao Liu, Bing Sun, Yongli Tian, Xingjun Zhou, Feng Hao, Xi Chun, Zhiqiang Wan, Peng Liu, Jingwen Wang, and Dagula Du
Atmos. Chem. Phys., 22, 12153–12166,Short summary
A single year’s offline measurement was conducted in Hohhot to reveal the chemical characteristics and sources of PM2.5 in a semi-arid region. We believe that our study makes a significant contribution to the literature because relatively few studies have focused on the chemical composition and sources of PM2.5 with offline measurements. A knowledge gap exists concerning how chemical composition and sources respond to implemented control measures for aerosols, particularly in a semi-arid region.
Diwei Wang, Zhenxing Shen, Qian Zhang, Yali Lei, Tian Zhang, Shasha Huang, Jian Sun, Hongmei Xu, and Junji Cao
The optical properties and molecular structure of atmospheric brown carbon (BrC) in winter of several megacities in China were analyzed, and the source contribution of brown carbon was improved by using positive matrix factorization coupled with multilayer perceptron neural network. These results can provide a basis for the more effective control of BrC to reduce its impacts on regional climates and human health.
Yindong Guo, Hongru Shen, Iida Pullinen, Hao Luo, Sungah Kang, Luc Vereecken, Hendrik Fuchs, Mattias Hallquist, Ismail-Hakki Acir, Ralf Tillmann, Franz Rohrer, Jürgen Wildt, Astrid Kiendler-Scharr, Andreas Wahner, Defeng Zhao, and Thomas F. Mentel
Atmos. Chem. Phys., 22, 11323–11346,Short summary
The oxidation of limonene, a common volatile emitted by trees and chemical products, by NO3, a nighttime oxidant, forms many highly oxygenated organic molecules (HOM), including C10-30 compounds. Most of the HOM are second-generation organic nitrates, in which carbonyl-substituted C10 nitrates accounted for a major fraction. Their formation can be explained by chemistry of peroxy radicals. HOM, especially low-volatile ones, play an important role in nighttime new particle formation and growth.
Shuaishuai Ma, Qiong Li, and Yunhong Zhang
Atmos. Chem. Phys., 22, 10955–10970,Short summary
The nitrate phase state can play a critical role in determining the occurrence and extent of nitrate depletion in internally mixed NaNO3–DCA particles, which may be instructive for relevant aerosol reaction systems. Besides, organic acids have a potential to deplete nitrate based on the comprehensive consideration of acidity, particle-phase state, droplet water activity, and HNO3 gas-phase diffusion.
Chong Han, Hongxing Yang, Kun Li, Patrick Lee, John Liggio, Amy Leithead, and Shao-Meng Li
Atmos. Chem. Phys., 22, 10827–10839,Short summary
We presented yields and compositions of Si-containing SOAs generated from the reaction of cVMSs (D3–D6) with OH radicals. NOx played a negative role in cVMS SOA formation, while ammonium sulfate seeds enhanced D3–D5 SOA yields at short photochemical ages under high-NOx conditions. The aerosol mass spectra confirmed that the components of cVMS SOAs significantly relied on OH exposure. A global cVMS-derived SOA source strength was estimated in order to understand SOA formation potentials of cVMSs.
Junling Li, Kun Li, Hao Zhang, Xin Zhang, Yuanyuan Ji, Wanghui Chu, Yuxue Kong, Yangxi Chu, Yanqin Ren, Yujie Zhang, Haijie Zhang, Rui Gao, Zhenhai Wu, Fang Bi, Xuan Chen, Xuezhong Wang, Weigang Wang, Hong Li, and Maofa Ge
Atmos. Chem. Phys., 22, 10489–10504,Short summary
Ozone formation is enhanced by higher OH concentration and higher temperature but is influenced little by SO2. SO2 can largely enhance the particle formation. Organo-sulfates and organo-nitrates are detected in the formed particles, and the presence of SO2 can promote the formation of organo-sulfates. The results provide a scientific basis for systematically evaluating the effects of SO2, OH concentration, and temperature on the oxidation of mixed organic gases in the atmosphere.
Alexandra L. Klodt, Marley Adamek, Monica Dibley, Sergey A. Nizkorodov, and Rachel E. O'Brien
Atmos. Chem. Phys., 22, 10155–10171,Short summary
We investigated photochemistry of a secondary organic aerosol under three different conditions: in a dilute aqueous solution mimicking cloud droplets, in a solution of concentrated ammonium sulfate mimicking deliquesced aerosol, and in an organic matrix mimicking dry organic aerosol. We find that rate and mechanisms of photochemistry depend sensitively on these conditions, suggesting that the same organic aerosol compounds will degrade at different rates depending on their local environment.
Yixin Li, Jiayun Zhao, Mario Gomez-Hernandez, Michael Lavallee, Natalie M. Johnson, and Renyi Zhang
Atmos. Chem. Phys., 22, 9843–9857,Short summary
Here we elucidate the production of COOs and their roles in SOA and brown carbon formation from m-xylene oxidation by simultaneously monitoring the evolution of gas-phase products and aerosol properties in an environmental chamber. A kinetic framework is developed to predict SOA production from the concentrations and uptake coefficients for COOs. This functionality-based approach reproduces SOA formation from m-xylene oxidation well and is applicable to VOC oxidation for other species.
Yunqi Shao, Aristeidis Voliotis, Mao Du, Yu Wang, Kelly Pereira, Jacqueline Hamilton, M. Rami Alfarra, and Gordon McFiggans
Atmos. Chem. Phys., 22, 9799–9826,Short summary
This study explored the chemical properties of secondary organic aerosol (SOA) that formed from photo-oxidation of single and mixed biogenic and anthropogenic precursors. We showed that SOA chemical properties in a mixed vapour system are mainly affected by the higher-yield precursor's oxidation products and products from cross-product formation. This study also identifies potential tracer compounds in a mixed vapour system that might be used in SOA source attribution in future ambient studies.
Nikou Hamzehpour, Claudia Marcolli, Kristian Klumpp, Debora Thöny, and Thomas Peter
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Dust aerosol from dried lakebeds contain besides mineral particles also soluble salts and (bio-)organic compounds. Here, we investigate ice nucleation (IN) activity of dust samples from Lake Urmia Playa, Iran. We find high IN activity of the untreated samples that decreases after organic matter removal but increases after removing soluble salts and carbonates, evidencing inhibiting effects of soluble salts and carbonates on the IN activity of organic matter and minerals, especially microcline.
Yangyang Liu, Yue Deng, Jiarong Liu, Xiaozhong Fang, Tao Wang, Kejian Li, Kedong Gong, Aziz U. Bacha, Iqra Nabi, Qiuyue Ge, Xiuhui Zhang, Christian George, and Liwu Zhang
Atmos. Chem. Phys., 22, 9175–9197,Short summary
Both CO2 and carbonate salt work as the precursor of carbonate radicals, which largely promotes sulfate formation during the daytime. This study provides the first indication that the carbonate radical not only plays a role as an intermediate in tropospheric anion chemistry but also as a strong oxidant for the surface processing of trace gas in the atmosphere. CO2, carbponate radicals, and sulfate receive attention from those looking at the environment, atmosphere, aerosol, and photochemistry.
Jack S. Johnson and Coty N. Jen
Atmos. Chem. Phys., 22, 8287–8297,Short summary
Sulfuric acid nucleation forms particles in Earth's atmosphere that influence cloud formation and climate. This study introduces the Nucleation Potential Model, which simplifies the diverse reactions between sulfuric acid and numerous precursor gases to predict nucleation rates. Results show that the model is capable of estimating the potency and concentration of mixtures of precursor gases from laboratory and field observations and can be used to model nucleation across diverse environments.
Xudong Li, Ye Tao, Longwei Zhu, Shuaishuai Ma, Shipeng Luo, Zhuzi Zhao, Ning Sun, Xinlei Ge, and Zhaolian Ye
Atmos. Chem. Phys., 22, 7793–7814,Short summary
This work has, for the first time, investigated the optical and chemical properties and oxidative potential of aqueous-phase photooxidation products of eugenol (a biomass-burning-emitted compound) and elucidated the interplay among these properties. Large mass yields exceeding 100 % were found, and the aqueous processing is a source of BrC (likely relevant with humic-like substances). We also show that aqueous processing can produce species that are more toxic than that of its precursor.
Ye Wang, Natalie Mahowald, Peter Hess, Wenxiu Sun, and Gang Chen
Atmos. Chem. Phys., 22, 7575–7592,Short summary
PM2.5 is positively related to anticyclonic wave activity (AWA) changes close to the observing sites. Changes between current and future climates in AWA can explain up to 75 % of PM2.5 variability at some stations using a linear regression model. Our analysis indicates that higher PM2.5 concentrations occur when a positive AWA anomaly is prominent, which could be critical for understanding how pollutants respond to changing atmospheric circulation and for developing robust pollution projections.
Clarissa Baldo, Akinori Ito, Michael D. Krom, Weijun Li, Tim Jones, Nick Drake, Konstantin Ignatyev, Nicholas Davidson, and Zongbo Shi
Atmos. Chem. Phys., 22, 6045–6066,Short summary
High ionic strength relevant to the aerosol-water enhanced proton-promoted dissolution of iron in coal fly ash (up to 7 times) but suppressed oxalate-promoted dissolution at low pH (< 3). Fe in coal fly ash dissolved up to 7 times faster than in Saharan dust at low pH. A global model with the updated dissolution rates of iron in coal fly ash suggested a larger contribution of pyrogenic dissolved Fe over regions with a strong impact from fossil fuel combustions.
Adam Brighty, Véronique Jacob, Gaëlle Uzu, Lucille Borlaza, Sébastien Conil, Christoph Hueglin, Stuart K. Grange, Olivier Favez, Cécile Trébuchon, and Jean-Luc Jaffrezo
Atmos. Chem. Phys., 22, 6021–6043,Short summary
With an revised analytical method and long-term sampling strategy, we have been able to elucidate much more information about atmospheric plant debris, a poorly understood class of particulate matter. We found weaker seasonal patterns at urban locations compared to rural locations and significant interannual variability in concentrations between previous years and 2020, during the COVID-19 pandemic. This suggests a possible man-made influence on plant debris concentration and source strength.
Linyu Gao, Junwei Song, Claudia Mohr, Wei Huang, Magdalena Vallon, Feng Jiang, Thomas Leisner, and Harald Saathoff
Atmos. Chem. Phys., 22, 6001–6020,Short summary
We study secondary organic aerosol (SOA) from β-caryophyllene (BCP) ozonolysis with and without nitrogen oxides over 213–313 K in the simulation chamber. The yields and the rate constants were determined at 243–313 K. Chemical compositions varied at different temperatures, indicating a strong impact on the BCP ozonolysis pathways. This work helps to better understand the SOA from BCP ozonolysis for conditions representative of the real atmosphere from the boundary layer to the upper troposphere.
Rongshuang Xu, Sze In Madeleine Ng, Wing Sze Chow, Yee Ka Wong, Yuchen Wang, Donger Lai, Zhongping Yao, Pui-Kin So, Jian Zhen Yu, and Man Nin Chan
Atmos. Chem. Phys., 22, 5685–5700,Short summary
To date, while over a hundred organosulfates (OSs) have been detected in atmospheric aerosols, many of them are still unidentified, with unknown precursors and formation processes. We found the heterogeneous OH oxidation of an α-pinene-derived organosulfate (C10H17O5SNa, αpOS-249, αpOS-249) can proceed at an efficient rate and transform into more oxygenated OSs, which have been commonly detected in atmospheric aerosols and α-pinene-derived SOA in chamber studies.
Bartłomiej Witkowski, Priyanka Jain, and Tomasz Gierczak
Atmos. Chem. Phys., 22, 5651–5663,Short summary
This article describes a comprehensive investigation of the aqueous oxidation of 4-nitrophenol (4NP) by hydroxyl radicals (OH). The reaction was carried out in a laboratory photoreactor. We report the formation of key intermediates under different pH conditions and the evolution of the light absorption of the reaction solution. The results provide new insights into the formation and removal (chemical bleaching) of light-absorbing organic aerosols (atmospheric brown carbon).
Qi Li, Jia Jiang, Isaac K. Afreh, Kelley C. Barsanti, and David R. Cocker III
Atmos. Chem. Phys., 22, 3131–3147,Short summary
Chamber-derived secondary organic aerosol (SOA) yields from camphene are reported for the first time. The role of peroxy radicals (RO2) was investigated using chemically detailed box models. We observed higher SOA yields (up to 64 %) in the experiments with added NOx than without due to the formation of highly oxygenated organic molecules (HOMs) when NOx is present. This work can improve the representation of camphene in air quality models and provide insights into other monoterpene studies.
Xiuli Wei, Haosheng Dai, Huaqiao Gui, Jiaoshi Zhang, Yin Cheng, Jie Wang, Yixin Yang, Youwen Sun, and Jianguo Liu
Atmos. Chem. Phys., 22, 3097–3109,Short summary
We demonstrated the usage of the Fourier transform infrared (FTIR) spectroscopic technique to characterize in real time the hygroscopic growth properties of nanoparticles and their phase transition micro-dynamics at the molecular level. We first realize real-time measurements of water content and dry nanoparticle mass to characterize hygroscopic growth factors. We then identify in real time the hydration interactions and the dynamic hygroscopic growth process of the functional groups.
Zhancong Liang, Yangxi Chu, Masao Gen, and Chak K. Chan
Atmos. Chem. Phys., 22, 3017–3044,Short summary
The properties and fate of individual airborne particles can be significantly different, leading to distinct environmental impacts (e.g., climate and human health). While many instruments only analyze an ensemble of these particles, single-particle Raman spectroscopy enables unambiguous characterization of individual particles. This paper comprehensively reviews the applications of such a technique in studying atmospheric particles, especially for their physicochemical processing.
Zhi-Hui Zhang, Elena Hartner, Battist Utinger, Benjamin Gfeller, Andreas Paul, Martin Sklorz, Hendryk Czech, Bin Xia Yang, Xin Yi Su, Gert Jakobi, Jürgen Orasche, Jürgen Schnelle-Kreis, Seongho Jeong, Thomas Gröger, Michal Pardo, Thorsten Hohaus, Thomas Adam, Astrid Kiendler-Scharr, Yinon Rudich, Ralf Zimmermann, and Markus Kalberer
Atmos. Chem. Phys., 22, 1793–1809,Short summary
Using a novel setup, we comprehensively characterized the formation of particle-bound reactive oxygen species (ROS) in anthropogenic and biogenic secondary organic aerosols (SOAs). We found that more than 90 % of all ROS components in both SOA types have a short lifetime. Our results also show that photochemical aging promotes particle-bound ROS production and enhances the oxidative potential of the aerosols. We found consistent results between chemical-based and biological-based ROS analyses.
Kelvin H. Bates, Guy J. P. Burke, James D. Cope, and Tran B. Nguyen
Atmos. Chem. Phys., 22, 1467–1482,Short summary
The main nighttime sink of α-pinene, a hydrocarbon abundantly emitted by plants, is reaction with NO3 to form nitrooxy peroxy radicals (nRO2). Using uniquely designed chamber experiments, we show that this reaction is a major source of organic aerosol when nRO2 reacts with other nRO2 and forms a nitrooxy hydroperoxide when nRO2 reacts with HO2. Under ambient conditions these pathways are key loss processes of atmospheric reactive nitrogen in areas with mixed biogenic and anthropogenic influence.
Sophia M. Charan, Yuanlong Huang, Reina S. Buenconsejo, Qi Li, David R. Cocker III, and John H. Seinfeld
Atmos. Chem. Phys., 22, 917–928,Short summary
In this study, we investigate the secondary organic aerosol formation potential of decamethylcyclopentasiloxane (D5), which is used as a tracer for volatile chemical products and measured in high concentrations both outdoors and indoors. By performing experiments in different types of reactors, we find that D5’s aerosol formation is highly dependent on OH, and, at low OH concentrations or exposures, D5 forms little aerosol. We also reconcile results from other studies.
Beatrix Rosette Go Mabato, Yan Lyu, Yan Ji, Yong Jie Li, Dan Dan Huang, Xue Li, Theodora Nah, Chun Ho Lam, and Chak K. Chan
Atmos. Chem. Phys., 22, 273–293,Short summary
Biomass burning (BB) is a global phenomenon that releases large quantities of pollutants such as phenols and aromatic carbonyls into the atmosphere. These compounds can form secondary organic aerosols (SOAs) which play an important role in the Earth’s energy budget. In this work, we demonstrated that the direct irradiation of vanillin (VL) could generate aqueous SOA (aqSOA) such as oligomers. In the presence of nitrate, VL photo-oxidation can also form nitrated compounds.
Zijun Li, Angela Buchholz, Arttu Ylisirniö, Luis Barreira, Liqing Hao, Siegfried Schobesberger, Taina Yli-Juuti, and Annele Virtanen
Atmos. Chem. Phys., 21, 18283–18302,Short summary
We compared the evolution of two types of secondary organic aerosol (SOA) particles during isothermal evaporation. The sesquiterpene SOA particles demonstrated higher resilience to evaporation than α-pinene SOA particles generated under comparable conditions. In-depth analysis showed that under high-relative-humidity conditions, particulate water drove the evolution of particulate constituents by reducing the particle viscosity and initiating chemical aqueous-phase processes.
András Hoffer, Ádám Tóth, Beatrix Jancsek-Turóczi, Attila Machon, Aida Meiramova, Attila Nagy, Luminita Marmureanu, and András Gelencsér
Atmos. Chem. Phys., 21, 17855–17864,Short summary
Due to the widespread use of plastics high amounts of waste are burned in households worldwide, emitting vast amounts of PM10 and PAHs into the atmosphere. In this work different types of common plastics were burned in the laboratory with a view to identifying potentially specific tracer compounds and determining their emission factors. The compounds found were also successfully identified in atmospheric PM10 samples, indicating their potential use as ambient tracers for illegal waste burning.
Shijie Liu, Dandan Huang, Yiqian Wang, Si Zhang, Xiaodi Liu, Can Wu, Wei Du, and Gehui Wang
Atmos. Chem. Phys., 21, 17759–17773,Short summary
A series of chamber experiments was performed to probe the individual and common effects of NH3 and NOx on toluene secondary organic aerosol (SOA) formation through OH photooxidation. The synergetic effects of NH3 and NOx on the toluene SOA concentration and optical absorption were observed. The higher-volatility products formed in the presence of NOx could precipitate into the particle phase when NH3 was added. The formation pathways of N-containing OAs through NOx or NH3 are also discussed.
Lucía Caudillo, Birte Rörup, Martin Heinritzi, Guillaume Marie, Mario Simon, Andrea C. Wagner, Tatjana Müller, Manuel Granzin, Antonio Amorim, Farnoush Ataei, Rima Baalbaki, Barbara Bertozzi, Zoé Brasseur, Randall Chiu, Biwu Chu, Lubna Dada, Jonathan Duplissy, Henning Finkenzeller, Loïc Gonzalez Carracedo, Xu-Cheng He, Victoria Hofbauer, Weimeng Kong, Houssni Lamkaddam, Chuan P. Lee, Brandon Lopez, Naser G. A. Mahfouz, Vladimir Makhmutov, Hanna E. Manninen, Ruby Marten, Dario Massabò, Roy L. Mauldin, Bernhard Mentler, Ugo Molteni, Antti Onnela, Joschka Pfeifer, Maxim Philippov, Ana A. Piedehierro, Meredith Schervish, Wiebke Scholz, Benjamin Schulze, Jiali Shen, Dominik Stolzenburg, Yuri Stozhkov, Mihnea Surdu, Christian Tauber, Yee Jun Tham, Ping Tian, António Tomé, Steffen Vogt, Mingyi Wang, Dongyu S. Wang, Stefan K. Weber, André Welti, Wang Yonghong, Wu Yusheng, Marcel Zauner-Wieczorek, Urs Baltensperger, Imad El Haddad, Richard C. Flagan, Armin Hansel, Kristina Höhler, Jasper Kirkby, Markku Kulmala, Katrianne Lehtipalo, Ottmar Möhler, Harald Saathoff, Rainer Volkamer, Paul M. Winkler, Neil M. Donahue, Andreas Kürten, and Joachim Curtius
Atmos. Chem. Phys., 21, 17099–17114,Short summary
We performed experiments in the CLOUD chamber at CERN at low temperatures to simulate new particle formation in the upper free troposphere (at −30 ºC and −50 ºC). We measured the particle and gas phase and found that most of the compounds present in the gas phase are detected as well in the particle phase. The major compounds in the particles are C8–10 and C18–20. Specifically, we showed that C5 and C15 compounds are detected in a mixed system with isoprene and α-pinene at −30 ºC, 20 % RH.
Daniel A. Knopf and Markus Ammann
Atmos. Chem. Phys., 21, 15725–15753,Short summary
Adsorption on and desorption of gas molecules from solid or liquid surfaces or interfaces represent the initial interaction of gas-to-condensed-phase processes that can define the physicochemical evolution of the condensed phase. We apply a thermodynamic and microscopic treatment of these multiphase processes to evaluate how adsorption and desorption rates and surface accommodation depend on the choice of adsorption model and standard states with implications for desorption energy and lifetimes.
Spiro D. Jorga, Kalliopi Florou, Christos Kaltsonoudis, John K. Kodros, Christina Vasilakopoulou, Manuela Cirtog, Axel Fouqueau, Bénédicte Picquet-Varrault, Athanasios Nenes, and Spyros N. Pandis
Atmos. Chem. Phys., 21, 15337–15349,Short summary
We test the hypothesis that significant secondary organic aerosol production can take place even during winter nights through the oxidation of the emitted organic vapors by the nitrate radicals produced during the reaction of ozone and nitrogen oxides. Our experiments, using as a starting point the ambient air of an urban area with high biomass burning activity, demonstrate that, even with sunlight, there is 20 %–70 % additional organic aerosol formed in a few hours.
Zirui Zhang, Wenfei Zhu, Min Hu, Kefan Liu, Hui Wang, Rongzhi Tang, Ruizhe Shen, Ying Yu, Rui Tan, Kai Song, Yuanju Li, Wenbin Zhang, Zhou Zhang, Hongming Xu, Shijin Shuai, Shuangde Li, Yunfa Chen, Jiayun Li, Yuesi Wang, and Song Guo
Atmos. Chem. Phys., 21, 15221–15237,Short summary
We comprehensively investigated the mass growth potential, oxidation degree, formation pathway, and mass spectra features of typical urban-lifestyle secondary organic aerosols (SOAs) including vehicle SOAs and cooking SOAs. The mass spectra we acquired could provide necessary references to estimate the mass fractions of vehicle and cooking SOAs in the atmosphere, which would greatly decrease the uncertainty in air quality evaluation and health risk assessment in urban areas.
Wenfei Zhu, Song Guo, Zirui Zhang, Hui Wang, Ying Yu, Zheng Chen, Ruizhe Shen, Rui Tan, Kai Song, Kefan Liu, Rongzhi Tang, Yi Liu, Shengrong Lou, Yuanju Li, Wenbin Zhang, Zhou Zhang, Shijin Shuai, Hongming Xu, Shuangde Li, Yunfa Chen, Min Hu, Francesco Canonaco, and Andre S. H. Prévôt
Atmos. Chem. Phys., 21, 15065–15079,Short summary
The experiments of primary emissions and secondary organic aerosol (SOA) formation from urban lifestyle sources (cooking and vehicles) were conducted. The mass spectral features of primary organic aerosol (POA) and SOA were characterized by using a high-resolution time-of-flight aerosol mass spectrometer. This work, for the first time, establishes the vehicle and cooking SOA source profiles and can be further used as source constraints in the OA source apportionment in the ambient atmosphere.
Adam Milsom, Adam M. Squires, Jacob A. Boswell, Nicholas J. Terrill, Andrew D. Ward, and Christian Pfrang
Atmos. Chem. Phys., 21, 15003–15021,Short summary
Atmospheric aerosols can be solid, semi-solid or liquid. This phase state may impact key aerosol processes such as oxidation and water uptake, affecting cloud droplet formation and urban air pollution. We have observed a solid crystalline organic phase in a levitated proxy for cooking emissions, oleic acid. Spatially resolved structural changes were followed during ageing by X-ray scattering, revealing phase gradients, aggregate products and a markedly reduced ozonolysis reaction rate.
Cheng Wu, David M. Bell, Emelie L. Graham, Sophie Haslett, Ilona Riipinen, Urs Baltensperger, Amelie Bertrand, Stamatios Giannoukos, Janne Schoonbaert, Imad El Haddad, Andre S. H. Prevot, Wei Huang, and Claudia Mohr
Atmos. Chem. Phys., 21, 14907–14925,Short summary
Night-time reactions of biogenic volatile organic compounds and nitrate radicals can lead to the formation of secondary organic aerosol (BSOANO3). Here, we study the impacts of light exposure on the BSOANO3 from three biogenic precursors. Our results suggest that photolysis causes photodegradation of a substantial fraction of BSOANO3, changes the chemical composition and bulk volatility, and might be a potentially important loss pathway of BSOANO3 during the night-to-day transition.
Mao Xiao, Christopher R. Hoyle, Lubna Dada, Dominik Stolzenburg, Andreas Kürten, Mingyi Wang, Houssni Lamkaddam, Olga Garmash, Bernhard Mentler, Ugo Molteni, Andrea Baccarini, Mario Simon, Xu-Cheng He, Katrianne Lehtipalo, Lauri R. Ahonen, Rima Baalbaki, Paulus S. Bauer, Lisa Beck, David Bell, Federico Bianchi, Sophia Brilke, Dexian Chen, Randall Chiu, António Dias, Jonathan Duplissy, Henning Finkenzeller, Hamish Gordon, Victoria Hofbauer, Changhyuk Kim, Theodore K. Koenig, Janne Lampilahti, Chuan Ping Lee, Zijun Li, Huajun Mai, Vladimir Makhmutov, Hanna E. Manninen, Ruby Marten, Serge Mathot, Roy L. Mauldin, Wei Nie, Antti Onnela, Eva Partoll, Tuukka Petäjä, Joschka Pfeifer, Veronika Pospisilova, Lauriane L. J. Quéléver, Matti Rissanen, Siegfried Schobesberger, Simone Schuchmann, Yuri Stozhkov, Christian Tauber, Yee Jun Tham, António Tomé, Miguel Vazquez-Pufleau, Andrea C. Wagner, Robert Wagner, Yonghong Wang, Lena Weitz, Daniela Wimmer, Yusheng Wu, Chao Yan, Penglin Ye, Qing Ye, Qiaozhi Zha, Xueqin Zhou, Antonio Amorim, Ken Carslaw, Joachim Curtius, Armin Hansel, Rainer Volkamer, Paul M. Winkler, Richard C. Flagan, Markku Kulmala, Douglas R. Worsnop, Jasper Kirkby, Neil M. Donahue, Urs Baltensperger, Imad El Haddad, and Josef Dommen
Atmos. Chem. Phys., 21, 14275–14291,Short summary
Experiments at CLOUD show that in polluted environments new particle formation (NPF) is largely driven by the formation of sulfuric acid–base clusters, stabilized by amines, high ammonia concentrations or lower temperatures. While oxidation products of aromatics can nucleate, they play a minor role in urban NPF. Our experiments span 4 orders of magnitude variation of observed NPF rates in ambient conditions. We provide a framework based on NPF and growth rates to interpret ambient observations.
Aristeidis Voliotis, Yu Wang, Yunqi Shao, Mao Du, Thomas J. Bannan, Carl J. Percival, Spyros N. Pandis, M. Rami Alfarra, and Gordon McFiggans
Atmos. Chem. Phys., 21, 14251–14273,Short summary
Secondary organic aerosol (SOA) formation from mixtures of volatile precursors can be affected by the molecular interactions of the products. Composition and volatility measurements of SOA formed from mixtures of anthropogenic and biogenic precursors reveal processes that can increase or decrease the SOA volatility. The unique products of the mixture were more oxygenated and less volatile than those from either precursor. Analytical context is provided to explore the SOA volatility in mixtures.
Andreas Tilgner, Thomas Schaefer, Becky Alexander, Mary Barth, Jeffrey L. Collett Jr., Kathleen M. Fahey, Athanasios Nenes, Havala O. T. Pye, Hartmut Herrmann, and V. Faye McNeill
Atmos. Chem. Phys., 21, 13483–13536,Short summary
Feedbacks of acidity and atmospheric multiphase chemistry in deliquesced particles and clouds are crucial for the tropospheric composition, depositions, climate, and human health. This review synthesizes the current scientific knowledge on these feedbacks using both inorganic and organic aqueous-phase chemistry. Finally, this review outlines atmospheric implications and highlights the need for future investigations with respect to reducing emissions of key acid precursors in a changing world.
Tao Cao, Meiju Li, Chunlin Zou, Xingjun Fan, Jianzhong Song, Wanglu Jia, Chiling Yu, Zhiqiang Yu, and Ping'an Peng
Atmos. Chem. Phys., 21, 13187–13205,Short summary
Brown carbon (BrC) fractions derived from biomass burning and coal combustion including water- and methanol-soluble organic carbon were comprehensively characterized for their optical and chemical properties, as well as oxidative potential. Moreover, the key components or functional groups that were responsible for the reactive oxygen species (ROS) generation capacity of BrC were also discussed. These findings are useful for estimation of their environmental, climate, and health impacts.
Zhen Mu, Qingcai Chen, Lixin Zhang, Dongjie Guan, and Hao Li
Atmos. Chem. Phys., 21, 11581–11591,Short summary
Sunlight affects the life and chemical composition of atmospheric aerosols and thus alters air quality. This study demonstrated that the photo-aging process not only changed the chemical compositions of chromophoric aerosols but also changed the roles of the chromophoric organic matter in the photo-aging process of aerosol. This study adds to our understanding of how sunlight affects chromophoric aerosol aging.
Louise N. Jensen, Manjula R. Canagaratna, Kasper Kristensen, Lauriane L. J. Quéléver, Bernadette Rosati, Ricky Teiwes, Marianne Glasius, Henrik B. Pedersen, Mikael Ehn, and Merete Bilde
Atmos. Chem. Phys., 21, 11545–11562,Short summary
This work targets the chemical composition of α-pinene-derived secondary organic aerosol (SOA) formed in the temperature range from -15 to 20°C. Experiments were conducted in an atmospheric simulation chamber. Positive matrix factorization analysis of data obtained by a high-resolution time-of-flight aerosol mass spectrometer shows that the elemental aerosol composition is controlled by the initial α-pinene concentration and temperature during SOA formation.
Yubo Cheng, Yiqiu Ma, and Di Hu
Atmos. Chem. Phys., 21, 10589–10608,Short summary
We conducted chemical characterization and source apportionment of PM2.5 in Hong Kong. Secondary formation was the leading contributor to organic carbon (OC) throughout the year. NOx processing played a key role in both daytime and nighttime secondary organic aerosol (SOA) production, and monoterpene SOA was the most abundant. Sulfate was positively related to total and secondary sulfate-related OC, and particle acidity was significantly correlated with SOC from aging of biomass burning.
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In this study, the influence of HCHO on renoxification on nitrate-doped TiO2 particles is investigated by using an experimental chamber. Mass NOx release is suggested to follow the NO−3-NO3·-HNO3-NOx pathway, with HCHO involved in the transformation of NO3· to HNO3 through hydrogen abstraction. Our proposed reaction mechanism by which HCHO promotes photocatalytic renoxification is helpful for deeply understanding the atmospheric photochemical processes and nitrogen cycling.
In this study, the influence of HCHO on renoxification on nitrate-doped TiO2 particles is...