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徐薇,修光利,陶俊,王丽娜,朱梦雅,黄众思,蔡婧,乔婷,张大年.上海市大气散射消光特征及其与颗粒物化学组成关系研究[J].环境科学学报,2015,35(2):379-385

Characterization of light scattering extinction and the relationship with particle components in Shanghai

基金项目：国家环境保护公益性行业科研专项(No.200809143);国家自然科学基金(No.21277044);上海市教委科研创新基金(No.12ZZ054);中央高校科研经费(No.WB1113005)

摘要：为研究上海市大气颗粒物散射系数分布特征以及颗粒物化学组分贡献率,2009年用浊度仪对散射系数进行观测,同时采集PM_2.5,分析其主要化学成分浓度.观测发现,秋、冬季散射系数较高,夏季最小.散射系数日变化有早、晚两个峰,午间出现低谷.散射系数与温度、风速有显著负相关性.多元回归得到OC、NO₃^-、NH₄⁺是影响消光系数的主要化学成分.依据IMPROVE估算公式,将OC分为吸湿性和非吸湿性部分,并加入海盐影响,使估算b_ext值更接近监测值.OC、EC和硫酸铵盐为估算消光系数主要贡献成分.

Abstract：This study aims to investigate the characteristics of scattering coefficients of particle distribution and the contribution of different chemical components in Shanghai. We used nephelometer to measure scattering coefficients in 2009. PM_2.5 was sampled and their chemical compositions were analyzed simultaneously. The results showed that scattering coefficients were high in fall and winter and low in summer. The diurnal variation displayed bimodal distribution in the morning and at night, respectively, and a though in the afternoon. The observed scattering coefficients were negatively significantly correlated with temperature and wind speed. EC, NO₃^- and NH₄⁺ were identified as the primary components responsible for extinction coefficient by means of multiple regression models. By separating OC into hygroscopic and non-hygroscopic parts and taking into consideration the role of sea salt ion concentration in the IMPROVE formula, we reached more accurate estimates of b_ext values. Furthermore, OC, EC and ammonium sulfate were the main components to estimate scattering coefficients.