西安大气细颗粒（P M1）化学组成及其对能见度的影响

摘要

在2012年秋季选取天气状况相对稳定的12 d,运用细颗粒化学组分在线观测仪(ACSM),观测西安大气颗粒物变化；利用正矩阵因子分析法(P MF )对大气细颗粒物中的有机物进行源解析,探讨其对能见度的影响；最后,结合IMPROVE公式中吸湿增长因子和多元线性回归统计方法重建散光系数.结果表明：在观测时段,PM1(不包括黑碳和矿尘等难熔组分)和 PM2．5质量浓度时间序列的相关性较好(判定系数为0．67),PM1约占PM2．5质量浓度的60％,有机物约占PM1质量浓度的58％,其他组分(包括SO2-4,NO-3,NH＋4和Cl-)约占42％；高相对湿度(大于85％)伴随着一次组分质量分数的增加,雨水对一次组分的湿沉降作用也更加明显；利用正矩阵因子分析法对有机物进行源解析,分解出烃类有机气溶胶(HOA)和氧化性有机气溶胶(OOA)两种组分；OOA 约占有机物质量浓度的54％,HOA约占46％,并且在下午时段,HOA 发生挥发,经过光化学反应快速转化为OOA；硝酸盐对光的散射贡献最大.%12 days with relative steady weather conditions in autumn of 2012 were selected,and the variation of atmospheric fine particle in Xi��an was measured by aerodyne aerosol chemical speciation monitor (ACSM);source apportionment of organics from atmospheric fine particle was analyzed by the means of positive matrix factorization (PMF),and the effect of atmospheric fine particle on visibility was discussed;finally,the scattering coefficient was reconstructed by the means of hygroscopic growth factors from IMPROVE equation and multi-linear regression statistical method.The results show that the correlation between time series of mass concentrations of non-refractory PM1 (except for black carbon and mineral dust)and PM2.5 is significant with a determination coefficient of 0.67 at the observation session;the mass concentration of non-refractory PM1 is about 60% of PM2.5 ,and the mass concentration of organic is about 58% of PM1 ,other components (including SO2-4 ,NO-3 ,NH+4 and Cl-)is about 42%;higher relative humidity increases the mass fraction of primary component,and rainfall significantly improves the wet deposition of primary component;hydrocarbon-like organic aerosol (HOA ) and oxygenated organic aerosol (OOA)are resolved from organics by the means of PMF;mass concentration of OOA is about 54% of organics,and that of HOA is about 46%;HOA volatilizes and translates to OOA after a photochemical reaction in the afternoon;nitrate contributes most to light scattering coefficient.