成都市PM10中碳质气溶胶长期来源特点

大气颗粒物中包含多种组分的气溶胶，其中碳质气溶胶由于对人体健康、能见度有较大影响，已受到越来越多的关注.为研究碳质气溶胶的长期变化规律，采集了成都市2009—2013年的PM₁₀样品，对其中所含的无机元素、水溶性离子及碳组分分别进行测定，并使用“PMF（正定矩阵因子分解法）-比值”模型分别对PM₁₀和所含的碳质气溶胶的来源进行分析.结果表明，1月、2月、5月和12月的碳质气溶胶浓度较高，其中1月、2月和12月的OC/EC（有机碳与元素碳质量浓度之比）较高，并且PMF-比值模型计算结果也显示冬季SOC增多，表明冬季可能有更多的二次有机碳（SOC）生成；5月的char-EC/soot-EC（二者质量浓度之比，其中char-EC=EC1-OP，soot-EC=EC2+EC3，它们可更好地区分源类）较高，K含量也较高，表明可能有更多的生物质燃烧排放.PM₁₀解析共发现6类源，依次为地壳扬尘（26.5%）、二次硫酸盐（25.1%）、燃煤&生物质燃烧混合源（17.3%）、二次硝酸盐&二次有机碳混合源（12.3%）、机动车源（11.8%）和水泥尘源（7.0%）；碳质气溶胶解析发现，OC主要来源依次为机动车源（38.2%）、燃煤&生物质燃烧混合源（33.1%）和二次有机碳（25.3%），char-EC的主要来源是燃煤&生物质燃烧混合源和机动车源，分别占50.5%和45.4%，soot-EC则主要受机动车影响（达73.2%）.研究显示，成都市PM₁₀主要来自于地壳扬尘、二次生成和燃煤&生物质燃烧，而碳质气溶胶主要来自于机动车、燃煤&生物质燃烧. 

Long-Term Source Characteristics of Carbonaceous Aerosol in PM10 of Chengdu City, China

Atmospheric particulate matter is comprised of a variety of components. Due to the large proportion and the influence on human health and visibility, the carbonaceous aerosol has attracted much attention. For the research on the long-term variation of carbonaceous aerosol, PM₁₀ samples were collected during 2009-2013 in Chengdu City. The inorganic elements, water-soluble ions and carbon composition were determined. Moreover, PMF-ratio model is applied to quantify the sources of PM₁₀ and carbonaceous aerosol. Results present that concentration of carbonaceous fractions shows it highest value in winter and May. OC/EC ratio is higher in winter and the modeled results show that SOC increased in winter, which might indicate more secondary carbon (SOC) in winter. Furthermore, char-EC/soot-EC and K concentration is higher in May, which may illustrate more biomass combustion in May. Six source categories are identified, including crust dust (26.5%), the secondary sulfate (25.1%), coal combustion & straw burning (17.3%), secondary nitrate & the secondary organic carbon (12.3%), vehicle exhaust (11.8%), cement dust (7.0%). Major contributors to OC in PM₁₀ are vehicular exhaust (38.2%), coal combustion & straw burning (33.1%) and SOC (25.3%). The coal combustion & biomass combustion and vehicle exhaust contributed 50.5% and 45.4% of char-EC. Vehicle exhaust dominates soot-EC (73.2%) in PM₁₀. PM₁₀ mainly comes from the crust dust, secondary sulfate, coal combustion & straw burning. The carbonaceous aerosol mainly comes from the vehicle exhaust and coal combustion & straw burning.