C. Wittbom, A. C. Eriksson, J. Rissler, P. Roldin, E. Z. Nordin, S. Sjogren, P. T. Nilsson, E. Swietlicki, J. Pagels, B. Svenningsson
{"title":"Effect of solubility limitation on hygroscopic growth and cloud drop activation of SOA particles produced from traffic exhausts","authors":"C. Wittbom, A. C. Eriksson, J. Rissler, P. Roldin, E. Z. Nordin, S. Sjogren, P. T. Nilsson, E. Swietlicki, J. Pagels, B. Svenningsson","doi":"10.1007/s10874-018-9380-5","DOIUrl":null,"url":null,"abstract":"<p>Hygroscopicity measurements of secondary organic aerosol (SOA) particles often show inconsistent results between the supersaturated and subsaturated regimes, with higher activity as cloud condensation nucleus (CCN) than indicated by hygroscopic growth. In this study, we have investigated the discrepancy between the two regimes in the Lund University (LU) smog chamber. Various anthropogenic SOA were produced from mixtures of different precursors: anthropogenic light aromatic precursors (toluene and <i>m</i>-xylene), exhaust from a diesel passenger vehicle spiked with the light aromatic precursors, and exhaust from two different gasoline-powered passenger vehicles. Three types of seed particles were used: soot aggregates from a diesel vehicle, soot aggregates from a flame soot generator and ammonium sulphate (AS) particles. The hygroscopicity of seed particles with condensed, photochemically produced, anthropogenic SOA was investigated with respect to critical supersaturation (<i>s</i><sub><i>c</i></sub>) and hygroscopic growth factor (<i>gf</i>) at 90% relative humidity. The hygroscopicity parameter <i>κ</i> was calculated for the two regimes: <i>κ</i><sub><i>sc</i></sub> and <i>κ</i><sub><i>gf</i></sub>, from measurements of <i>s</i><sub><i>c</i></sub> and <i>gf</i>, respectively. The two <i>κ</i> showed significant discrepancies, with a <i>κ</i><sub><i>gf</i></sub> /<i>κ</i><sub><i>sc</i></sub> ratio closest to one for the gasoline experiments with ammonium sulphate seed and lower for the soot seed experiments. Empirical observations of <i>s</i><sub><i>c</i></sub> and <i>gf</i> were compared to theoretical predictions, using modified K?hler theory where water solubility limitations were taken into account. The results indicate that the inconsistency between measurements in the subsaturated and supersaturated regimes may be explained by part of the organic material in the particles produced from anthropogenic precursors having a limited solubility in water.</p>","PeriodicalId":611,"journal":{"name":"Journal of Atmospheric Chemistry","volume":"75 4","pages":"359 - 383"},"PeriodicalIF":3.0000,"publicationDate":"2018-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s10874-018-9380-5","citationCount":"6","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Atmospheric Chemistry","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1007/s10874-018-9380-5","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 6
Abstract
Hygroscopicity measurements of secondary organic aerosol (SOA) particles often show inconsistent results between the supersaturated and subsaturated regimes, with higher activity as cloud condensation nucleus (CCN) than indicated by hygroscopic growth. In this study, we have investigated the discrepancy between the two regimes in the Lund University (LU) smog chamber. Various anthropogenic SOA were produced from mixtures of different precursors: anthropogenic light aromatic precursors (toluene and m-xylene), exhaust from a diesel passenger vehicle spiked with the light aromatic precursors, and exhaust from two different gasoline-powered passenger vehicles. Three types of seed particles were used: soot aggregates from a diesel vehicle, soot aggregates from a flame soot generator and ammonium sulphate (AS) particles. The hygroscopicity of seed particles with condensed, photochemically produced, anthropogenic SOA was investigated with respect to critical supersaturation (sc) and hygroscopic growth factor (gf) at 90% relative humidity. The hygroscopicity parameter κ was calculated for the two regimes: κsc and κgf, from measurements of sc and gf, respectively. The two κ showed significant discrepancies, with a κgf /κsc ratio closest to one for the gasoline experiments with ammonium sulphate seed and lower for the soot seed experiments. Empirical observations of sc and gf were compared to theoretical predictions, using modified K?hler theory where water solubility limitations were taken into account. The results indicate that the inconsistency between measurements in the subsaturated and supersaturated regimes may be explained by part of the organic material in the particles produced from anthropogenic precursors having a limited solubility in water.
期刊介绍：
The Journal of Atmospheric Chemistry is devoted to the study of the chemistry of the Earth''s atmosphere, the emphasis being laid on the region below about 100 km. The strongly interdisciplinary nature of atmospheric chemistry means that it embraces a great variety of sciences, but the journal concentrates on the following topics:
Observational, interpretative and modelling studies of the composition of air and precipitation and the physiochemical processes in the Earth''s atmosphere, excluding air pollution problems of local importance only.
The role of the atmosphere in biogeochemical cycles; the chemical interaction of the oceans, land surface and biosphere with the atmosphere.
Laboratory studies of the mechanics in homogeneous and heterogeneous transformation processes in the atmosphere.
Descriptions of major advances in instrumentation developed for the measurement of atmospheric composition and chemical properties.
京公网安备 11010802042870号
京ICP备2023020795号-1
分享
求助内容：
应助结果提醒方式：
扫码关注我们
