In situ detection of the chemistry of individual fog droplet residues in the Pearl River Delta region, China. Issue 15 (3rd August 2016)

• Record Type: Journal Article
• Authors: Bi, Xinhui; Lin, Qinhao; Peng, Long; Zhang, Guohua; Wang, Xinming; Brechtel, Fred J.; Chen, Duohong; Li, Mei; Peng, Ping'an; Sheng, Guoying; Zhou, Zhen
• Is Part Of: Journal of geophysical research. Volume 121:Issue 15(2016)
• Page Start: 9105
• Page End: 9116
• Publication Date: 2016-08-03
• Subjects: fog -- mixing state -- chemical composition -- GCVI -- single particle -- PRD; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2016JD024886
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: We use a single‐particle aerosol mass spectrometer coupled with a ground‐based counterflow virtual impactor to measure the chemical compositions of individual submicron fog droplet residues. This is the first report on single particle mass spectrometry measurements of fog droplet residual particles at ground level in an urban area. We show that most of the fog droplet residues were composed of elemental carbon (EC) (67.7%), followed by K‐rich (19.2%) and mineral dust/metal (12.3%) particles. The predominance of EC‐containing particles demonstrated that these particles could be effective fog nuclei and highlights the important influence of anthropogenic emissions on regional climate system. Compared with interstitial and ambient aerosols, nitrate was enhanced, sulfate was depressed, and ammonium‐ and organics‐containing particles were hardly found in the fog droplet residues during fog events, suggesting that dust and metal particles containing nitrate may be preferentially activated and that ammonium and organics may not play important roles in fog formation in Guangzhou. We also present direct observational evidence that trimethylamine and hydroxymethanesulfonate are not found within fog droplet residues, although we previously observed enhanced gas‐to‐particle partitioning of these compounds by fog processing. Additionally, higher fraction or intensities of [K] +, [Fe] +, and [SiO3 ] − were found in fog droplet residues than in ambient and interstitial particles. Key Points: The first report of single‐particle mass spectrometry measurements of fog droplet residues at ground level Most fog droplet residues are composed of elemental carbon Trimethylamine and hydroxymethanesulfonate are not found in the fog droplet residues