西宁市城区冬季PM2.5和PM10中有机碳、元素碳污染特征

2014年11月—2015年1月对西宁市冬季开展PM_(2.5)和PM_(10)的连续监测。利用DRI 2001A型热光碳分析仪(美国)对有机碳和元素碳进行分析,结果表明:西宁市冬季PM_(2.5)和PM_(10)中碳气溶胶所占比例分别为33.13%±6.83%、24.21%±6.27%,说明碳气溶胶主要集中在PM_(2.5)中;OC/EC值均大于2,说明西宁市大气中存在二次污染;SOC占PM_(2.5)和PM_(10)的质量浓度比例分别为46.50%和57.40%,PM_(2.5)中SOC浓度占PM_(10)中SOC浓度的61.88%,说明SOC主要存在于PM_(2.5)中,且SOC形成的二次污染和直接排放的一次污染都是西宁市碳气溶胶的主要来源;与其他城市比较发现,西宁市冬季PM_(2.5)中的碳气溶胶含量普遍高于其他城市,PM_(10)中OC质量浓度相对其他城市较高,EC质量浓度偏低;OC和EC的相关性不显著,说明来源不统一;进一步对OC和EC各组分质量浓度进行分析知,西宁市冬季碳气溶胶主要来源于机动车汽油排放、燃煤和生物质燃烧。

Characteristics of Organic Carbon and Elemental Carbon in PM2.5 and PM10 in Xining in the Winter

PM_2.5 and PM₁₀ were monitored continuously from November, 2014 to January, 2015. Organic carbon and elemental carbon were measured by DRI 2001A, which from the Desert Research Institute in the United States. The results show that the ratios of TC in PM_2.5 and PM₁₀ are 33.13%±6.83%, 24.21%±6.27%, TC Mainly concentrated in PM_2.5in Xining Winter. The ratio of OC/EC is over 2, that is to say secondary pollution exists in Xining Winter. The ratios of secondary organic carbon(SOC) in PM_2.5 and PM₁₀ are 46.50%, 57.40%, the mass concentration of SOC in PM_2.5 account for 61.88% of SOC in PM₁₀, thatmeans SOC mainly in the PM_2.5, the secondary pollution and the original pollution are all the mainly pollute resources of carbon aerosol in Xining Winter. Compared with other cities, the mass concentration of carbon aerosol in PM_2.5 are higher than most of the other cities, the mass concentration of OC in PM₁₀ are higher than most of the other cities, but EC are lower. The correlation between OC and EC is not significant, so the source of OC and EC is not uniform. Analyzed the mass concentration of components of OC and EC know carbon aerosol mainly comes from coal combustion, vehicle exhaust and biomass burning in Xining Winter.