Source identification of trace elements in the atmosphere during the second Asian Youth Games in Nanjing, China: Influence of control measures on air quality

Abstract

An intensive field campaign was carried out at Nanjing Bureau of Meteorology located on the Jiangxin island during July 28-Aug 30, 2013. Concentrations of 15 trace metal elements (Al, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Ba, Pb Pd) were measured in the daily collected PM2.5 filter samples by the inductively coupled plasma mass spectrometry (ICP-MS). Mass loading of Zn was found to be higher than other elements, even higher than Al, indicating that the airborne Zn in this region may have multiple sources including traffic emissions, emissions from ship paintings and ship-fuel burning. Six sources, which are coal combustion, soil dust, traffic, industry, electroplate and electronic pollution, and Cr source were identified by combining positive matrix factorization (PMF) analysis and the control measures of air quality during the Asian Youth Games (Aug 16–24, 2013, “control period”). Source contributions from coal combustion and industry were obviously reduced during the control period, while contributions from traffic, electronic pollution and Cr source increased, indicating the importance of the specific pollutants due to anthropogenic activities. Based on the meteorological data and air mass back trajectories, air parcels originated from southeast direction may deliver pollutants from industrial emissions containing elements of Co, Zn, Cd, Ba, Pb and Pd, while the air masses arriving in Nanjing from directions of Fujian and Zhejiang provinces contained high concentrations of As, Sr, and Cu, likely from combustion sources.