基于PMF的武汉市大气细颗粒物消光来源解析

利用武汉2020年7月(夏季)和10月(秋季)的在线观测数据,同时将颗粒物的光学参数和化学组分数据输入正定矩阵因子分解(PMF)源解析模型,对PM_2.5消光系数的源贡献进行定量解析.研究发现,对吸收系数贡献较大的源为机动车(66.3%)和工业源(14.2%),对散射系数贡献较大的源为以硝酸盐为主的二次无机盐Ⅰ(38.4%)和机动车(27.0%),光散射的源贡献率呈现出明显的季节变化,二次无机盐Ⅰ在夏季(14.6%)的贡献较秋季(47.4%)显著降低.消光系数源贡献方面,夏季机动车(37.2%)和以硫酸盐为主的二次无机盐Ⅱ(21.2%)对消光的贡献较大,而秋季主要的消光源为二次无机盐Ⅰ(44.7%)和机动车(26.7%).最后,还获取了几个重要源的波长吸收指数(AAE)值:机动车(0.96)、工业源(1.04)、扬尘(1.39)、生物质燃烧(2.24).

PMF model based atmospheric aerosol light extinction budget source apportionment study in Wuhan.

Online observation data from Wuhan in July (summer) and October (autumn) in 2020 was used to quantify the source contribution of PM_2.5 on light extinction coefficients by inputting the optical parameters and chemical components of PM_2.5 into the positive matrix factorization (PMF) model. This study found that the dominating contributing sources of light absorption coefficient were vehicles (66.3%) and industry (14.2%). For light scattering coefficient, the major contributors were secondary inorganic aerosol Ⅰ (38.4%) and vehicle (27.0%). The source contribution on light scattering showed clear seasonal variations, as the contribution from secondary inorganic aerosol Ⅰ was notably lower in summer (14.6%) than in autumn (47.4%). As for the light extinction coefficient, vehicles (37.2%) and secondary inorganic aerosol Ⅱ (21.2%) were the major contributors in summer, while secondary inorganic aerosol Ⅰ (44.7%) and vehicles (26.7%) were the dominating sources in autumn. The absorption Ångström exponent (AAE) values for several important sources were also obtained in this study, including vehicles (0.96), industry (1.04), dust (1.39), and biomass burning (2.24).