成都市黑碳气溶胶污染特征及与气象因子的关系

CHARACTERISTICS OF BLACK CARBON AEROSOL POLLUTION IN CHENGDU AND THE RELATIONSHIP BETWEEN METEOROLOGICAL FACTORS

为系统了解成都市黑碳气溶胶（BC）的污染特征,利用四川省环境监测站提供的成都市人民南路四段2013年9月至2014年7月逐时BC监测数据,对其浓度进行了统计分析。结果表明：1）BC小时平均浓度变化范围较大,介于0.01-57.83μg/m^3,浓度中值（5.17μg/m^3）小于平均值（7.32μg/m^3）,即BC小时浓度具有偏态分布特征。2）BC日均浓度变化范围为2-28.2μg/m^3,其浓度日变化在四季均呈明显的单谷型,谷值出现在16：00时附近,表现为从凌晨到10：00时变化较平稳,10：00—16：00时浓度急剧下降,16：00到夜间浓度急剧上升;浓度季变化呈现出冬高夏低,春秋平稳的基本特征。3）秋、冬、春、夏四季BC本底浓度值分别为2.49,5.05,2.89,2.43μg/m^3。4）BC质量浓度与PM2.5和PM10变化趋势一致,BC浓度相对颗粒物浓度变化较快,在0.01水平上与PM2.5和PM10均呈显著正相关,相关系数分别为0.657、0.638,与温度、降水和风速均呈负相关,相关系数分别为-0.334,-0.338,-0.202。

To obtain a systematic understanding of pollutant characteristics of black carbon（ BC） in Chengdu,statistical analysis on concentration is conducted based on hourly BC monitoring data derived from Sept. 2013 to Jul. 2014 at the 4th Section of South Renmin Road in Chengdu,provided by Monitoring Station of Sichuan. The results showed as follows： 1） The hourly average concentration variation range of BC was larger,about 0. 01 - 57. 83 μg / m^3. The mid-value（ 5. 17 μg / m^3） was lower than the average value（ 7. 32 μg / m^3）,which means hourly concentration of BC was characterized by skew distribution.2） Daily mean concentration of BC ranged from 2 to 28. 2 μg / m^3,which presented an obvious single-valley model over seasons,whose valley value appears at 4pm. It showed that the concentration had a smooth change from wee hours to 10 am,declined sharply from 10 am to 4pm and then had a sharp rise from 4pm till night. Seasonal concentration variation exhibited an essential feature which was high in winter and low in summer with steady change in spring and autumn. 3） The background values of BC concentration are 2. 49,5. 05,2. 89,2. 43 μg / m^3 respectively for autumn,winter,spring and summer. 4） The variation tendency of mass concentration of BC appeared consistent with that of PM2. 5and PM10. The BC concentration,changing faster relative to particle concentration,had significantly positive correlation with PM2. 5and PM10 and the correlation coefficients were 0. 657 and 0. 638 respectively at the 0. 01 level,while it had negative correlation with temperature,precipitation and wind speed,whose correlation coefficients were- 0. 334,- 0. 338,- 0. 202,respectively.