南京北郊冬季气溶胶散射特征及其与PM2.5化学组成的关系  

Aerosol Scattering Property and the Relationship with PM_(2.5) Chemical Component during Winter in the Northern Suburb of Nanjing

作　　者：张程 于兴娜[1] 沈丽[1] 吕睿[1] 肖思晗 时政 

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室,气候与环境变化国际合作联合实验室,气象灾害预报预警与评估协同创新中心,中国气象局气溶胶与云降水重点开放实验室,江苏南京210044

出　　处：《生态环境学报》2018年第1期101-107,共7页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(91544229;41475142;41775154);国家重点研发计划项目(2016YFC0203501);江苏省高校“青蓝工程”项目;江苏高校优势学科建设工程项目(PAPD)

摘　　要：为了深入了解南京北郊冬季气溶胶散射特征以及PM_(2.5)化学组分对其贡献情况,2015年1月使用积分浊度仪获取散射系数数据,同时利用KC-120H采样器对PM_(2.5)样本进行采集,并通过离子色谱仪对所采集的PM_(2.5)样本的化学组分进行分析。结果表明,观测期间PM_(2.5)质量浓度与气溶胶散射系数的日均值分别为(126.46±68.55)μg·m^(-3)和(423.36±265.34)Mm^(-1),两者变化趋势基本类似且均随污染程度的升高而上升,散射系数与PM_(2.5)质量浓度的相关性较好,相关系数r高达0.93。通过对散射系数小时平均值进行统计后发现,散射系数出现频率最高的两个区间分别为100~200 Mm^(-1)和400~500 Mm^(-1)。观测地区冬季日均散射系数变化呈"三峰型"分布,峰值分别出现在05:00、14:00以及18:00—20:00。日均散射系数在清洁天中呈现"双峰型"分布,在两种污染天中则呈"三峰型"分布。通过IMPROVE方程重建各个化学组分与散射系数之间的关系发现,重建后的散射系数与实测散射系数之间相关性较高(r=0.896),说明IMPROVE方程能够较好地反映PM_(2.5)中主要化学组分对散射系数的贡献情况。根据贡献率计算可知,NH_4NO_3、(NH_4)_2SO_4和OC是南京北郊冬季不同大气污染程度中气溶胶散射系数增大最为主要的贡献源。利用HYSPLIT-4在线模式分析了1月24日、28日和30日3个不同污染天的48 h气团后向轨迹后发现,局地源排放为南京北郊颗粒物质量浓度上升的主要原因。This study aims to investigate the aerosol scattering characteristics and the contribution of different chemical compositions of PM2.5 in the northern suburb of Nanjing, China. The scattering coefficient was measured by nephelometer in January 2015. The PM2.5 was sampled by KC-120H sampler and its chemical compositions were analyzed by ion chromatography. The results showed that the daily PM2.5 mass concentration and the scattering coefficient was （126.46±68.55） μg·m-3 and （423.36±265.34） Mm-1, respectively . The trend variation of scattering coefficient showed agreement with the mass concentration of PM2.5 （r=0.93）. The maximum frequency distributions of the scattering coefficient were 100~200 Mm-1 and 400~500 Mm-1. The diurnal variation of scattering coefficient during the total measurement period showed a three-peak shape with peaks at 05：00, 14：00 and 18：00-20：00. The scattering coefficient showed a double-peak shape on clean days while a three-peak shape on pollution days. The reconstructed scattering coefficient correlated closely with the measured value （r=0.896）. This result indicated that the IMPROVE equation could be used to reflect the relationship between the scattering coefficient and the chemical compositions. NH4NO3, （NH4）2SO4 and OC was the main contributors to the scattering coefficient. According to the HYSPLIT-4 model, the emission of a local source was the main reason for the increase of particulate matter in the tested area of Nanjing.

关 键 词：散射特征 PM2.5 污染程度 化学组分 

分 类 号：X16[环境科学与工程—环境科学]