Analysis of a serious air pollution event resulting from crop residue burning over Nanjing and surrounding regions

摘要

During the time period between Oct.28 to Oct.29, 2008, a serious air pollution event took place in Nanjing and surrounding regions, accompanying with sharply increasing of PM10, CO and SO2 in the air. Satellite remote sensing data, surface meteorological observations, air pollution index and the NCEP reanalysis data were used to investigate the atmospheric conditions and planetary boundary layer (PBL) features. Air mass backward trajectory simulation method was employed to analyze the sources of the air pollutants and transport paths of this event. The results show that the transport of gas pollutants released from crop residue burning in the central and north parts of Jiangsu province, combining with unfavorable weather condition, which is the dominating reason of this air pollution episode. It is found there was a high-pressure system with relative uniform pressure pattern, weak vertical velocity, vorticity and divergence below 500hPa, which prevents atmospheric ventilation. The inversion temperature, low mixing height and topographical forcing winds in the PBL are also not favorable for the diffusion and transport of the air pollutants.