10th International Aerosol Conference
September 2 - September 7, 2018
America's Center Convention Complex
St. Louis, Missouri, USA

Abstract View


Variations of PM2.5 Chemical Components and Its Source Apportionment during Winter Season from 2013 to 2017 in Beijing of China

HEZHONG TIAN, Panyang Shao, Huanjia Liu, Bobo Wu, Weizhao Liang, Shuhan Liu, School of Environment, Beijing Normal University

     Abstract Number: 1224
     Working Group: Air Quality in Megacities: from Sources to Control

Abstract
By analyzing the chemical components (water-soluble inorganic ions, carbonaceous components and trace elements) of multi-size airborne particles (PM2.5, PM1, PM10) sampled from December 15, 2016 to January 15, 2017 in Beijing, as well as the associated gaseous pollutants and meteorological parameters, we investigated the variation characteristics between haze and normal days and compared them with the well-documented haze episode in January 2013. Higher ambient temperature (AT), higher relative humidity (RH) and low wind speed (WS) are common meteorological characteristics during winter haze periods. With strict atmospheric pollution control measures over the past four years, concentrations of SO2, SO42- and most anthropogenic elements have decreased whereas NO3- and NH4+ concentration in PM2.5 increased by as high as 77.9% and 47.3% respectively in the sampling period of 2016-2017 winter compared with January 2013. Secondary inorganic aerosol (SIA) increased sharply and significantly aggravated haze episodes, in which nitrate has replaced sulfate to be the dominating component in PM2.5 although the rapid growth of sulfate still played an important role in the formation and evolution of extremely heavy haze events. With ammonium-rich condition and high RH, NO3- was thought to mainly be produced by enhanced heterogeneous reactions. The heaviest Cross 2017 New Year’s Haze episode was characterized by strong secondary reactions and external transport of anthropogenic pollutions from south of Beijing. In consequence, it can be concluded that urban air pollution in Beijing has shifted from being dominated by coal burning to a mix of vehicle emissions and coal burning. It’s quite crucial to cut NOx, NH3 and SO2 emissions simultaneously and strengthen inter-regional air pollution prevention and control work in preventing winter haze in Beijing.