Optical properties and chemical apportionment of s

Authors: Fenping Cui Mindong Chen Yan Ma Jun Zheng Lei Yao Yaoyao Zhou

Publish Date: 2016/02/27

Volume: 73, Issue: 2, Pages: 119-135

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Abstract

A field measurement of aerosol optical properties and chemical composition was carried out from August 25 2012 to September 6 2012 in Nanjing China A threewavelength PhotoAcoustic Soot Spectrometer PASS3 was used to measure aerosol scattering and absorption coefficient B sca and B abs with the wavelength dependent 405 532 781 nm Samples were also collected by a Particle into Liquid Sampler PILS with a time resolution of 1 hour and water soluble chemical composition was analyzed by ion chromatography IC The hourly average B sca were 2399 ± 1153 1859 ± 993 and 938 ± 598 Mm−1 while the average B abs were 335 ± 218 239 ± 157 and 167 ± 117 Mm−1 for 405 532 and 781 nm The air mass from Shandong province to Northwest of Nanjing SN brought rich chemical composition which can enhance aerosol optical properties The largest B sca ~3899 3219 1805 Mm−1 B abs ~597 430 310 Mm−1 ω532 ~089 and lowest visibility ~32Km Å sca 405/781 ~119 were observed during SN period The mass concentrations of organic carbon OC elemental carbon EC and water soluble inorganic ions NH4 + K+ NO3 − and SO4 2− also continued to increase However aerosol optical properties and chemical composition kept stable for the episode with the air mass from Oceanic Regions OR Ammonium sulfate NH42SO4 ammonium nitrate NH4NO3 organic mass OM elemental carbon EC fine soil FS and sea salt SS contributed 491 40 316 93 59 and 01  to the total extinction coefficient in summer NH42SO4 OM and EC were dominant chemical components and the total contribution of them reached to 90  of the dry aerosol extinction The proportion of NH42SO4 increased whereas OM and EC showed a decrease during SN period Our study indicated that the summertime aerosol pollution at the northern suburb of Nanjing was mainly attributed to agricultural biomass burning and secondary aerosol formation The longrange transport plays an important role in the formation of haze episodes in summertime of NanjingThis research was financially supported by Commonweal Program of Environment Protection Department of China Grant No 201409027–05 International ST Cooperation Program of China ISTCP Grant No 2014DFA90780 and Postgraduate Innovation Foundation of Jiangsu Province Grant No CXZZ11 0611

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