乌鲁木齐市碳质气溶胶季节变化及其对霾形成的影响

Seasonal Variation of Carbonaceous Aerosol and Its Effect on Haze Formation in Urumqi

应用热光碳分析仪测定乌鲁木齐2013年四季PM_(2.5)样品中有机碳(OC)和元素碳(EC)的质量浓度,并分析其四季变化特征。结果表明:OC、EC最高值出现在冬季,分别为(17.7±7.3)μg·m^(-3)和(7.0±2.6)μg·m^(-3),OC、EC在PM_(2.5)中的百分含量最高值也出现在冬季。冬季OC、EC相关性最低,表明冬季污染物来源最复杂。在冬季光化学条件不利的情况下,二次有机碳(SOC)生成量却达到最大值,显示出前提物对SOC生成的巨大影响。另外,通过分析霾日和非霾日OC、EC和无机离子的变化特征,表明:SO_4^(2-)、NH_4^+和SOC对霾形成的影响最大。

The values of organic carbon（ OC） and elemental carbon（ EC） in P（2.5 membrane film in 2013 were measured using the thermo-optical carbon analyzer so as to analyze the variation of carbonaceous aerosols in Urumqi.The results showed that the maximum values of OC and EC,（ 17. 7 ± 7. 3） μg·m^-3 and（ 7. 0 ± 2. 6） μg·m^-3 respectively,occurred in winter. The highest percentages of OC and EC in PM2.5 appeared also in winter. The correlation between OC and EC was the lowest in winter,and the pollution sources in winter were the most complicated. Under the disadvantageous photochemical circumstances,the production of secondary organic carbon（ SOC） reached the maxima,which revealed that the primary precursor pose affected greatly the formation of SOC. In addition,through analyzing the variations of OC,EC and inorganic ions on haze and non-haze days,it was found that SO4^2-,NH4^＋and SOC affected the greatest the haze formation.