华东乡村站点气溶胶吸收特性的观测研究

Observational study on aerosol absorption at a rural site in Northern China

利用2014—2015年安徽淮南观测站的黑碳仪观测数据,分析华东乡村代表性地区气溶胶吸收特性的变化特征及其影响因子。研究表明,观测期间520 nm波段的气溶胶吸收系数平均为(24.6±18.4)Mm-1,且存在显著的波长依赖性,吸收波长指数平均为1.3±0.2,这与该地区较高的生物质燃烧排放有关。利用吸收系数与波长的关系,分离获得生物质燃烧排放的除黑碳以外的其他气溶胶的吸收波长指数,平均为2.7±0.7,在此基础上,进一步对吸收系数进行分离,发现每年5—6月、10月到次年1月是该地区受生物质燃烧影响较为严重的时期,以2014年6月为例,本地秸秆焚烧和江浙一带污染物的区域输送过程,是导致淮南地区污染加重的主要原因。

Based on the observational data monitored by Aethalometer at the site of Shangyao in Huainan during 2014—2015, aerosol absorption properties and their impact factors of the typical rural area in Northern China were analyzed. During the observation period, the average absorption coefficient was（24.6±18.4） Mm-1 in 520 nm, showing strong spectrum dependence. The average absorption Angstrom exponent was 1.3 ±0.2, which indicated that biomass burning emissions in Huainan were serious and noteworthy. With the relations between absorption coefficients and wavelengths, the absorption Angstrom exponent of brown carbon aerosols from biomass burning was obtained, with an average of 2.7 ±0.7. Besides, the absorption coefficient was separated into two parts. Results showed that Huainan was most significantly affected by biomass burning from May to Jun, and October to January. In June 2014, for example, the heavy pollution in Huainan was mainly due to the crop straw burning occurred in local and the regional air pollution transported from Jiangsu and Zhejiang province.