Study On Long-term Variation Of Black Carbon Aerosol Over Peking And Hebei Province During2006-2012

Black carbon aerosols is an important ingredient in the atmospheric aerosol, and also a particular component in haze pollution. Many studies based on the analysis of one site have shown that the black carbon aerosols concentrations related to local transportation, local surface wind speed etc.. Regional studies of black carbon aerosols is still relatively rare, therefore this article comes into being. We analyzing the long time seriesvariation in Beijing and Hebei province of black carbon aerosols mass concentration, and the features of black carbon aerosol data within the same area at different sites, aim to a better understanding in BC within this region and to establish the basis of black carbon concentration long-term changing features in this region for further research.Using trend analysis, synthesis analysis, EEMD, kernel density estimation, probability and mathematical statistics method,we devoteto studying thelong-term black carbon aerosol data in Beijing, Shangdianzi, and Gucheng. Combined with three sites of meteorological data (rainfall, average wind speed and direction),we try to reveal the influence of meteorological factors on changes in the concentration of black carbon.The black carbon concentration in Beijing significantly decreased, and the trend coefficient is-0.086μg/(m3·month). Black carbon aerosol mass concentration in Shangdianzi station showed a slight upward trend throughout2006-2012, and the trend coefficient is0.013μg/(m3·month), and in Gucheng black carbon concentration basically unchanged overall. Beijing, Shangdianzi and Gucheng seasonal variations of black carbon mass concentrations were lower in spring and summer, synchronous small fluctuations among the data, and higher during the fall and winter, also with related the data fluctuations more. Black carbon concentration in three stations demonstrates low daytime diurnal variation especially in the afternoon appeared minimun and high concentration of carbon black at night. Under windy weather condition, black carbon mass concentrations were lower than black carbon concentration under light wind weather conditions. Black carbon aerosol in Beijing and Gucheng has more concentrations under non-precipitation. The BC concetration absolute value of discrepance under two different precipitation conditions in two stations are1.75μg/m3,1.85μg/m3respectively. But in Shangdianzi, BC concentration under that two conditions has not much differences. Gucheng, Beijing, Shangdianzi are situated in a southwest-northeast pollutant transport channel in Huabei Plain. Northeast and southwest airflow will bring black carbon concentrations to Shangdianzi.Wind speed and wind direction impacts less on the cumulative or evident process in Gucheng than that in Beijing, suggesting high concentrations of black carbon emissions from local sources in Gucheng.Black carbon concentrations, PM10and PM2.5were analyzed in Beijing and were found black carbon concentrations greater when PM10or PM2.5little, indicating that the contribution of black carbon concentration when air pollution is relatively small, the severe polluted weather in Beijing is not primarily affected by carbon black.