Variation of PM2.5 concentration in Hangzhou, China--颗粒学报PARTICUOLOGY

Hong, S., Jiao, L., & Ma, W. (2013). Variation of PM2.5 concentration in Hangzhou, China. Particuology, 11(1), 55–62. https://doi.org/10.1016/j.partic.2012.04.008

Variation of PM_2.5concentration in Hangzhou, China

Shengmao Hong ^a *, Li Jiao ^a, Wanli Ma ^b

a Environment Science, Hangzhou Central Station for Environmental Monitoring, 4, Hangda Road, Hangzhou 310007, Zhejiang, China
b Hangzhou Bureau of Meteorology, No. 218 Fengshanxincun, Hangzhou 310007, Zhejiang, China

10.1016/j.partic.2012.04.008

Volume 11, Issue 1, February 2013, Pages 55-62

Received 6 December 2011, Revised 28 March 2012, Accepted 26 April 2012, Available online 24 November 2012.

E-mail: honglaomao@hotmail.com

Highlights

► PM_2.5 concentration and its ratio to PM₁₀ in different weather systems in Hangzhou were studied.

► Nine weather systems were classified through 11-year weather charts from 1996 to 2006.

► The highest PM_2.5 concentration coincided with large-scale continuous pollution events.

► Weather system forecast can be used as guidance on pollutants emission control.

Abstract

This observational study investigates the variation of PM_2.5 concentration and its ratio against PM₁₀ concentration under different weather systems and pollution types. The study was conducted in Hangzhou on east China's Yangtze River Delta using data collected at seven ambient air quality monitoring stations around the metropolitan area between 2006 and 2008 and using weather information in the same period. Nine predominant weather systems affecting the city were classified through careful analysis of the 11-year surface and upper air weather charts from 1996 to 2006. Each observational day was then assigned to one of the nine weather systems. It was found that the PM_2.5 concentration varied greatly for different weather systems, with the highest PM_2.5 concentration associated with the post-cold-frontal system at 0.091 mg/m³ and the lowest PM_2.5 concentration with the easterlies system at 0.038 mg/m³, although the PM_2.5/PM₁₀ ratio remained consistently above 0.5 for all systems. The post-cold-frontal system typically occurs in autumn and winter while the easterlies system is more a summer phenomenon. Among all types of pollution, the highest PM_2.5 concentration of 0.117 mg/m³ coincided with the large-scale continuous pollution events, suggesting that this type of pollution was more conducive to the formation of secondary particulate matters. The ratio of PM_2.5/PM₁₀ was above 0.5 in non-pollution days and all pollution types but one under the influence of dust storms when the ratio decreased to 0.3 or less. The outcomes of this study could be used to develop a rudimental predictive model of PM_2.5 concentration based on weather system and pollution type.

Graphical abstract

Keywords

PM_2.5; Concentration; Weather system; Secondary particulate matter; Post-cold-frontal; Large-scale continuous pollution

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