南宁市夏季和冬季细颗粒物化学组分特征研究

Analysis of Chemical Species Characteristics in Fine Particles in Nanning During Summer and Winter

以南宁市大气细颗粒物化学组分的污染特征为研究对象,分析了2013年夏季和冬季PM2.5样品中水溶性离子、碳组分和无机元素成分。结果表明,3类成分的质量浓度分别占PM2.5质量浓度的29.8%,34.9%,4.2%。水溶性离子主要成分为SO42-,NH4+,NO3-和K+。夏季离子成分NO3-,SO42-,NH4+与PM2.5质量浓度相关系数分别为0.947,0.956和0.967,三者之间的相关系数均高于0.97,具有同源性。南宁市OC平均质量浓度占颗粒物质量比重的28.2%,是颗粒物的主要成分之一。ρ(OC)/ρ(EC)均高于2.0,说明南宁市存在除污染源直接排放的一次有机碳外,还有来自大气化学过程形成的二次有机碳。不同无机元素中,Ca平均质量浓度最大,约2 000 ng/m3及以上,主要来源于建筑尘。

This research focuses on the pollution characteristics analysis of chemical species in atmospheric fine particles in Nanning. Three components, including water-soluble ions, carbon fraction and inorganic element, of PM2.5samples in 2013 summer and winter were analyzed. The results showed that average mass concentrations of the three components in PM2.5were29.8%, 34.9% and 4.2%, respectively. The most abundant water-soluble ions were SO42-,NH4＋,NO3-and K＋. In the summer,PM2.5were strong relativity with NO3-,SO42-,NH4＋. The correlation coefficients were 0.947, 0.956 and 0.967. All the coefficient of association between NO3-, SO42-and NH4＋exceeded 0.97, which suggested that they had homology. The average mass concentrations of OC in PM2.5in Nanning was 28.2%, which indicated that the main component of PM2.5was OC. OC / EC ratio was higher than 2.0, which indicated that there might be secondary organic carbon generated from the atmospheric chemical processes besides primary organic carbon in Nanning. The average mass concentration of Ca was above 2 000 ng/m3, which was the highest among all the inorganic elements, and the major source of Ca2＋might be the construction dust.