广州PM2.5中有机碳和元素碳的污染特征

Characteristics of Organic Carbon（ OC） and Elemental Carbon（ EC） in PM2.5 in Guangzhou,China

于2015年6月~2016年5月对广州大气细粒子PM2.5进行持续观察,分析了样品中有机碳(organic carbon,OC)和元素碳(elemental carbon,EC)的含量.结果表明:广州大气PM2.5含量为(66.03±43.11)μg·m^-3,OC含量为(8.19±5.01)μg·m^-3,EC含量为(1.75±0.80)μg·m^-3;OC,EC和总碳(total carbon,TC)占PM2.5的比例分别为16.73%,3.85%和20.58%,表明广州细粒子的碳污染程度较为严重;PM2.5,OC和EC污染都呈现冬季>春季>夏季>秋季的特征,与历史研究基本一致;OC,EC相关系数较高(R2=0.929),表明二者来源较为相近,且PM2.5中EC1占比例最高(45.41%),表明广州燃煤和机动车尾气是重要的污染源;二次有机碳(SOC)为(4.10±3.56)μg·m^-3,占OC的比例为46.19%,表明广州二次有机碳的排放与形成是碳污染的重要因素.与历史数据相比,广州大气污染情况有所改善,碳气溶胶污染几乎达到历史最低值.

Continuous observation was conducted in Guangzhou from June 2015 to May 2016 and the content of OC and EC of PM2.5 samples were determined. The results show that the daily average concentration of PM2.5 in Guangzhou is( 66.03±43.11) μg·m^-3,which OC is( 8.19±5.01) μg·m^-3 and EC is( 1.75±0.80) μg·m^-3.OC,EC and TC account for 16.73%,3.85% and 20.58% of PM2.5,respectively,which indicates more severe carbonaceous pollution in Guangzhou. The degree of contamination of PM2.5,OC and EC shows winter > spring>summer> autumn,which is basically consistent with historical research;the correlation coefficient of OC and EC is 0.929,which shows that their source are rather similar;the highest percentage of EC1 in PM2.5 is 45.41%,which indicates that coal combustion and vehicle exhaust are important sources of particulate pollution in Guangzhou. The average mass concentration of secondary organic carbon( SOC) is( 4. 10 ± 3. 56) μg · m^-3,account for 46.19% of OC,which indicates that the emission and formation of SOC in Guangzhou is an important factor of carbonaceous pollution. Compared with historical data,air pollution of Guangzhou has improved,carbon aerosol pollution almost reach its lowest value in history.