Hygroscopic growth of aerosol scattering coefficient: A comparative analysis between urban and suburban sites at winter in Beijing--颗粒学报PARTICUOLOGY

Yan, P., Pan, X., Tang, J., Zhou, X., Zhang, R., & Zeng, L. (2009). Hygroscopic growth of aerosol scattering coefficient: A comparative analysis between urban and suburban sites at winter in Beijing. Particuology, 7(1), 52–60. https://doi.org/10.1016/j.partic.2008.11.009

Hygroscopic growth of aerosol scattering coefficient: A comparative analysis between urban and suburban sites at winter in Beijing

Peng Yan ^a *, Xiaole Pan ^a, Jie Tang ^a, Xiuji Zhou ^a, Renjian Zhang b, Limin Zeng ^c

a Key Laboratory for Atmospheric Chemistry (LAC), Center for Atmospheric Watch and Services of CMA, Chinese Academy of Meteorological Sciences, Beijing 100081, China
b Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
c College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China

10.1016/j.partic.2008.11.009

Volume 7, Issue 1, 18 February 2009, Pages 52-60

Received 17 July 2008, Accepted 5 November 2008, Available online 13 January 2009.

E-mail: yanpeng@cams.cma.gov.cn

Highlights

Abstract

A humidity controlled inlet system was developed to measure the hygroscopic growth of aerosol scattering coefficient in conjunction with nephelometry at an urban site of Chinese Academy of Meteorological Sciences (CAMS) in Beijing and a rural site at Shangdianzi Regional Background Air Pollution Monitoring Station (SDZ) outside Beijing during winter, from December 2005 to January 2006. Measurements were carried out at a wavelength of 525 nm with an Ecotech M9003 nephelometer. The hygroscopic growth function (or factor) of the aerosol scattering coefficient f(RH) increased continuously with increasing relative humidity (RH) and showed no obvious “step-like” deliquescent behavior at both sites during the experiment. The average growth factor f(RH) at the SDZ site could reach 1.5 when RH increased from less than 40% to 92%, and to 2.1 at the CAMS site when RH increased from less than 40% to 93%. The average hygroscopic growth factor at a relative humidity of 80%, f(RH = 80 ± 1%), was found to be about 1.26 ± 0.15 at CAMS and 1.24 ± 0.11 at SDZ. Further analysis indicated that under relatively polluted conditions, the average hygroscopic growth factor was higher at the CAMS site than that at the SDZ site. However, under relatively clean air conditions, the difference between the two sites was small, showing a hygroscopic growth behavior similar to those of burning biomass or blowing dust. These results reflected the different characteristics of aerosol types at the two sites.

Graphical abstract

Keywords

Humidity control inlet system; Aerosol scattering coefficient; Hygroscopic growth factor

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