Comparison of characteristics of elements in PM2.5 at urban sites (Beijing and Gwnagju) during winter season

Abstract

In Northeast Asia, the interest of PM2.5 has been increased since the environment problems such as fog and severe haze reveal with rapid development of industry and economy. Elements in PM2.5 are directly linked to sources of PM2.5 such as traffic related emissions, industrial pollutants, burning of fossil fuels and deposition in atmosphere. In this study, PM2.5 samples were collected from two metropolitan cities - Beijing, China and Gwangju, Korea in January 03-February 02, 2018, and the elements in PM2.5 samples analyzed by Energy Dispersive X-ray fluorescence (ED-XRF) from the two sites were compared. Chemical mass balance (CMB) was conducted to estimate the potential source contributors at both sites. Pearson’s R correlation and principle component analysis (PCA) analyses with literature survey about potential sources were used to estimate the source contribution of the aerosol samples and Hysplit backward trajectories are classified by using clustering method. The result shows elements in Beijing was mainly composed of Si, Ca, Fe, Al, S and K and most of them were constituents of the crustal elements while S, Si, Cl, K and Al elements were dominant in Gwnagju which is considered to be influenced by combustion sources and crustal elements, high PM2.5 mass concentration at Beijing affected by slow air mass coming from the northwest direction which was characterized by elements S, Zn, Cl and As which is indicative of coal burning while Gwangju affected by air mass coming from the west consisting S, Zn, Cl and As fraction suggesting mixed source from combustion and traffic sources. During sampling period, January 16 at Beijing had the highest PM2.5 mass concentration which are mainly affected by dust. After 2 days, the elements concentration at Gwangju was significant increased by Si, Al, Fe, K and Mg indicating dust and daily coefficient of divergence on January 18 is relatively similar with PKU CP than other days of GIST. This suggested that high mass concentration of PM2.5 at Gwangju might be affected by PM2.5 at Beijing. This study can be used for basic data for emission, generation by reaction and long-range transported aerosol model.