An approach to investigate new particle formation in the vertical direction on the basis of high time-resolution measurements at ground level and sea level. (February 2015)

• Record Type: Journal Article
• Authors: Meng, He; Zhu, Yujiao; Evans, Greg J.; Yao, Xiaohong
• Is Part Of: Atmospheric environment. Volume 102(2015)
• Page Start: 366
• Page End: 375
• Publication Date: 2015-02
• Subjects: New particle formation -- Particle growth -- FMPS -- Vertical transport -- Coefficient of variation; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2014.12.016
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: In this study, we investigated new particle formation (NPF) in the vertical direction using high time-resolution (1 s) measurements made by Fast Mobility Particle Sizers at ground level and at sea level. The coefficient of variation (CV), i.e., the ratio of standard deviation to mean value for <100-nm particle number concentration (N100 ) in every 30 s, is introduced as a metric to distinguish horizontal and vertical transport of atmospheric particles. We first examined the CV metric using the data collected at a semi-urban site in Toronto during the summer of 2007. The 50th and 95th percentiles of CVs associated with horizontal transport were 1–13 times smaller than those during strong vertical transport. We then compared the N100, GMD55 (geometric mean diameter of <55-nm particles) and GMD100 corresponding to the 0–5th percentiles of CVs with those corresponding to the 95–100th percentiles of CVs in five NPF events. The comparative results are discussed in terms of different formation and growth rates in the vertical direction. The similar analysis was also conducted in various marine atmospheres. We found that the CV metric can improve our understanding of NPF in the vertical direction. Highlights: CV metric can be adopted to study NPF in the vertical direction. Formation and growth rates of new particle were different in the vertical direction. New particle was predominantly from horizontal transport in inland atmospheres. New particle was generally from vertical transport in marine atmospheres.