Abstract：Jiangsu Province experienced a serious haze event during the period of October 27-30, 2008. The API (air pollution index) of the main 13 cities in the province increased sharply during the period. Here, we reported a study of exploring the pollution characteristic and the mechanism of this haze event with emphasizing the concentrations variation of polluting components, the synoptic operation and the source of the heavy haze event. The analysis was conducted by combining the data of concentrations of PM10, SO2, O3, NH3, NOx, and CO collected in Pukou (i.e., an observational station in the suburb area) and Gaochang Gate (i.e., an observational station in the urban area), some other conventional observation meteorological data, and the track analysis of the HYSPLIT4 model. Our analysis showed that the concentrations of PM10, NOx, and CO were positively correlated with the occurrence and development of the haze event, while the concentration of NH3 had no significant correlation with the haze event. The comparison of the data from these two observation stations (i.e., Pukou and Gaochang Gate) showed that the concentrations of SO2 and O3 were much lower in the urban area than those in the suburb area because SO2 was easily oxidized during the period of transmission and the convergence of O3 occurred in the urban area. In addition, we found that the concentrations of CO、NOx were much higher in the urban area than in the suburb area due to the huge amount of motor vehicles emission. Furthermore, the Heat Island Effect in the city made the atmospheric stratification steady at night and reduces the diffusion of pollutants. There was a northwestern flow behind the trough line at the pressure level of 500 mbar in the area of Jiangsu Province, so there was no precipitation event in this area. Steady circumfluence and warm advection before the ridge warms the middle atmosphere and hence made the haze event last a long time during a large region. On the other hand, there was a weak high pressure at the surface in the area of Jiangsu Province, so the atmospheric current flowed downward the area to make the upward diffusion of pollutants and turbulence was restrained. Finally, the scattered isobar equated the small horizontal gradient of pressure, which resulted in the low wind speed. Therefore, the pollutants could not diffuse horizontally quickly. The dense PM10 intensified the scattering of particles and resulted in the decrease of visibility, which was the main characteristic of the haze weather. The low wind speed and low humidity at the surface were also among the most important conditions for the development of the haze weather. By tracking the air mass from the simulations of the HYSPLIY4 model, we found that the pollutants related to the haze mainly come from the mid-eastern part of Henan Province, north of Jiangsu and Anhui Provinces. Most of areas in these provinces were the main bases of grain. Farmers reap grained during the end of October that left lots of straws on the cropland. In addition, farmers often burned the straws instead of reusing. Simultaneously the satellite NOAA-18 observed many fire dots in these areas before the haze. Therefore, the burning of straws in these areas was probably related to this haze event in Jiangsu Province.
朱佳雷, 王体健, 邢莉, 穆青, 周德荣. 江苏省一次重霾污染天气的特征和机理分析[J]. 中国环境科学, 2011, 31(12): 1943-1950.
ZHU Jia-Lei, WANG Ti-Jian, XING Li, MU Qing, ZHOU De-Rong. Analysis on the characteristics and mechanism of a heavy haze episode in Jiangsu Province. . CHINA ENVIRONMENTAL SCIENCECE, 2011, 31(12): 1943-1950.
