Analysis of daily and seasonal variation of fine particulate matter (PM2.5) for five cities of China

Monitoring of air quality is demanding, especially in poor air quality regions. China has been suffering from PM2.5 pollution associated with the fast urbanization and economic productivity. The purpose of this work is to analyze PM2.5 with regard to air quality for five populated cities (Beijing, Chengdu, Guangzhou, Shanghai and Shenyang) of China. In this study, hourly concentration of PM2.5 is decomposed into annual and seasonal concentrations and is evaluated. The results show the downward trend of PM2.5 for Beijing and Chengdu from 2013 to 2016 and for Guangzhou from 2012 to 2016, but no clear trend is observed for Shanghai and Shenyang. Although trend is decreasing for three cities (Beijing, Chengdu, Guangzhou), but overall annual average is found higher than the annual U.S. national ambient air quality standards for PM2.5. Among all five cities, highest annual PM2.5 concentration is found to be 104.1 µgm−3for Beijing in 2010 and lowest (32.6 µgm−3) is found for Guangzhou in 2016. The diurnal variation is high during night for Beijing, Guangzhou and Shanghai and it is high after morning rush hours for Chengdu and Shenyang (during April 2008–June 2017), respectively. In all studied sites, the seasonal variability is found highest in winter and lowest in the summer. Due to more contribution from biomass burning and dust, high PM2.5 variation is also found in the autumn and spring, respectively. To the best of our knowledge, this is the first study for Guangzhou, Chengdu and Shenyang that explores PM2.5 concentration for 5 years.