西安市黑碳气溶胶浓度特征及与气象因素和常规污染物相关性

利用西安市环境监测站超级站2013年9月1日—2015年5月31日黑碳气溶胶(BC)的监测数据,研究空气中BC浓度特征及其与气象因素和常规污染物相关性。结果表明:BC小时平均浓度均值在春季、夏季和冬季的变化趋势呈"W"型,秋季呈"V"型,且冬季的第一个最低值和峰值比春季和夏季的分别延迟1 h和2~3 h,且20:00~次日6:00秋季BC小时平均浓度均值高于当年冬季。BC浓度在秋季和冬季较高,夏季较低。冬季BC/PM_(2.5)基本最低,秋季BC/PM_(2.5)相对最高。BC日平均浓度与气温、降水和风速的日平均值为极负显著相关,且风速小于1.0 m/s时,其与风速呈最显著的负相关。除O_3外,BC日平均浓度与其他常规空气污染物浓度呈显著相关,表明其同源性很强,且受机动车尾气排放的影响更大。

Concentration Characteristics and the Correlations of Black Carbon Aerosols with Meteorological Factors and Conventional Pollutants in Xi'an

The characteristics of black carbon aerosol (BC) concentration, its correlations with meteorological factors and normal pollutants were studied by the monitoring data of BC from September 1, 2013 to May 31, 2015 in super station of Xi''an Environmental Monitoring Center. The results showed that diurnal variation of BC hour average concentration trends in spring, summer and winter were similar to "W" type, and the autumn trends liked "V" type. The first minimum value and the peak value of the BC hour average concentrations in winter respectively delayed 1 h and 2-3 h than those in spring and summer. The BC hour average concentrations in autumn were higher than those in winter from 20 o''clock to 6 o''clock. The BC concentrations were higher in autumn and winter, loweer in summer. The BC/PM_2.5 was the lowest in winter basically and it was the highest in autumn relatively. The BC daily average concentration had negative significant correlations with the daily average of temperature, precipitation and wind speed. When the wind speed was less than 1.0 m/s, the BC daily average concentration had the most significant negative correlation with that of the wind speed. In addition to the O₃, the BC daily average concentration was significantly correlated with the concentrations of other conventional air pollutants. Their significant correlations showed that the BC had very strong common origins with other normal pollutants. And the BC had been affected more by motor vehicle exhaust.