Aerosol Optical Properties over Beijing during the World Athletics Championships and Victory Day Military Parade in August and September 2015

Abstract

A special period in Beijing from 6 August to 17 September 2015, during which the World Athletics Championships and Victory Day military parade took place, and which involved measures to restrict traffic and reduce factory emissions, was selected to analyze the aerosol optical properties and the impact of meteorological conditions on pollution levels. The study was based on AERONET observational and retrieval data, particulate matter measurements (TEOM 1405), meteorological data, and then the HYSPLIT model was used to analyze the pollution sources. The study period was divided into three sub-periods according to the different stages of implementation of the control measures, and the main conclusions can be summarized as follows. During the period in which the restrictive measures were applied, the air quality improved significantly, with the average value of the AOD being 0.34˘0.20, about 69% less than before. Meanwhile, the average Ångström exponent was about 9.5% higher than before, with an average value of 1.38˘0.25, indicating that the main pollutants were fine particles. Single scattering albedo decreased as wavelength increased, being higher than in the other two stages (mean value of 0.944˘0.045). This showed that the strong scattering capacity and absorption aerosol optical depth was at its lowest, at about 0.008˘0.009. The peaks of aerosol volume concentration in the fine and coarse mode were significantly reduced. Meteorological conditions also had a certain effect on the aerosol optical properties, with the blowing of clean and dry wind and the occurrence of precipitation contributing to the overall improvement in air quality.

The optical, physical properties and direct radiative forcing of urban columnar aerosols in Yangtze River Delta, China

“…from 1.0 to 1.4 is more resulted from the fine particles. The results here are rather consistent with the ones inYu et al (2011),Qi et al (2016), andZheng et al (2016).…”

“…Most studies on the aerosol optical properties in China mainly focus on AOD and AE in short term (i.e., episodes, Che et al, 2013;Zheng et al, 2016;Che et al, 2015b). Studies on annual (Yu et al, 2011) and decadal (Che et al, 2015a)…”

“…Recently, substantial observation-based studies have conducted on the surface (e.g., Bergin et al, 2001;Xu et al, 2002;Zhang et al, 2004;Xia et al, 2007;Yan et al, 2008;He et al, 2009;Fan et al, 2010;Cai et al, 2011;Xu et al, 2012;Wu et al, 2012;Zhang et al, 2015;Yu et al, 2016;etc. ) and columnar (e.g., Chiang et al, 2007;Pan et al, 2010;Yu et al, 2011;Zhao et al, 2013;Tao et al, 2014;Zhu et al, 2014;2015a, b, c;Xia et al, 2016;Zheng et al, 2016;Qi et al, 2016, etc. ) aerosol optical properties and direct radiative forcing, especially on aerosols in China.…”

The optical properties, physical properties and direct radiative forcing of urban columnar aerosols in the Yangtze River Delta, China

“…The detailed calculations and corrections of the AAC at the site were presented by Zhuang et al (2015). Additionally, the monthly mean AOD and AE of the total aerosols from the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) were used in the analysis.…”

Investigation of the Optical Properties of Aerosols over the Coastal Region at Dalian, Northeast China

“…focused on cities experiencing rapid economic growth and highly polluted regions characterized by high aerosol loads [28][29][30][31][32][33][34][35]. However, few studies have been reported using ground-based measurements of the optical properties of aerosols over Northeast China [36][37][38][39].…”