西安黑碳气溶胶的污染特征及其成因分析

对2006年3月～2007年2月在西安获得的黑碳气溶胶观测资料及相关气象资料进行分析。结果表明,西安黑碳气溶胶浓度变化幅度很大,全年黑碳日均浓度变化范围为1400～30000ng·m-3,平均值为10000ng·m-3。在春、秋、冬3季其浓度日变化具有明显的双峰特征。西安市黑碳浓度秋、冬季节的月份高,春、夏月份低。黑碳季节平均浓度分别为春季9400ng·m-3,夏季为7100ng·m-3,秋季12000ng·m-3,冬季11900ng·m-3。黑碳浓度的频次分布表明低浓度值在春季和夏季所占比例大大高于秋、冬季节。研究发现气象要素(风速和混合层高度)对黑碳浓度有重要的影响。

Variability of Black Carbon Aerosol and Analysis of Influence Factors Over Xi'an Atmosphere

The atmospheric black carbon aerosols were measured continuously at Xi'an,during Mar. 2006～Feb. 2007. The black carbon concentrations at Xi'an varied acutely over a range of 1 400～30 000 ng/m3, with the average value of 10 000 ng/m3 in daily mean concentration. Obvious diurnal variation was observed,with the highest hourly average concentrations in the morning and night during three seasons,the black carbon concentrations showed a clear seasonal pattern with high concentrations in autumn and winter and low values in spring and sum- mer. The seasonal black carbon concentrations were 9 400, 7 100, 12 000, 11 900 ng/m3 for spring,summer,autumn and winter, respectively. The frequency distribution of black carbon concentrations showed a seasonal pattern. The influences of wind speed and mixed layer depth were discussed,which showed the black carbon concentrations were strongly affected by the variations of them.