利用天津城市边界层观测站2010年8月12日~9月18日期间的黑碳、污染物和气象梯度观测数据,分析天津市夏季黑碳气溶胶浓度的变化特征及其影响因子.结果表明,观测期间,黑碳气溶胶浓度均值为6.309μg/m3,占PM10质量浓度的4.17%,其吸收消光占气溶胶总体消光的10.23%.受人类活动和边界层结构影响,黑碳气溶胶浓度日变化呈双峰型,7:00达到峰值,14:00~16:00最小,20:00达到次高峰.黑碳气溶胶浓度随风速增加呈下降趋势,当风速超过4m/s时,浓度一般低于5μg/m3,西风及西北风对天津城区黑碳气溶胶输送作用明显,其出现大于10μg/m3的高黑碳气溶胶事件概率为18.07%;逆温和大气稳定易造成黑碳气溶胶在近地层的堆积,形成高污染事件.
Based on the observational gradient date of black carbon aerosol(BC),pollutants,and meteorological data at Tianjin boundary layer station from August 12 to September 18,2010,characteristics and influencing factors of BC concentration variation were analyzed.The average concentration of BC was 6.309mg/L and its mass percentage in PM10 was 4.17%.The absorption of BC accounted for 10.23% of total aerosol extinction.Influenced by human activity and boundary layer structure,the diurnal variation of BC showed two peaks,peaked at 7:00,lowest during 14:00~16:00,and the second peak at 20:00.BC concentration decreased with wind speed increasing.The BC concentration was generally lower than 5 mg/L when the wind speed higher than 4m/s.West and northwest wind had obvious transportation effect on BC in Tianjin city.The probability of high BC events with the concentration greater than 10mg/L was 18.07%.Inversion and atmospheric stability could lead to BC accumulate in the near surface layer and form high pollution events.