天津市颗粒物散射消光特征及化学组分贡献研究

摘要

To know the aerosol optical characterization and scattering extinction contribution of chemistry composition, an online observation work of light scattering coefficient was made, PM2.5 sampling was also made on January, April, July and October which was taken as typical 4months of its seasons. The light scattering coefficient was higher in autumn and winter than in spring and summer. A relation analysis showed that the mass scattering coefficient of PM2.5 in winter was 5.18m2/g, which was the highest of the whole year. Transportation and dissolution were obvious when the wind speed was above 3m/s; RH played an important increase role on light scattering coefficient when it was high enough. OC and sulfate in PM2.5 might be the main composition that affected the light scattering coefficient by the multi linear regression analysis. Based on the method of IMPROVE to calculate the contribution of chemical composition, organics contributed 38.51% of the total scattering coefficient, which was of the highest.%为研究天津大气颗粒物光学特征及不同化学成分贡献水平,对颗粒物散射系数进行了在线观测,同时对全年1,4,7,10 4个典型月份进行PM2.5采样,并分析其化学成分.观测发现,天津市散射消光系数表现为秋、冬季高,春、夏季低,冬季PM2.5的干散射效率最高,为5.18m2/g.当风速大于3m/s时,对污染物的清除扩散作用较为明显,散射系数较低；相对湿度较高时,其对散射系数的增长作用显著.多元线性回归分析结果表明,天津市细颗粒中有机碳和硫酸盐是影响天津市能见度的主要组分.根据IMPROVE法核算化学组分对散射消光的贡献,得出有机物的贡献最大,为38.51％.