南京2013年12月初持续重污染天气特征及成因分析

摘要

利用空气质量监测及气象观测数据，对2013年12月初南京市持续重污染天气特征及成因进行分析，结果表明：此次过程表现出污染程度重、持续时间长及细颗粒物占比大等特征，其中 PM2．5日均质量浓度最高达327μg ／m3，超标3．36倍；各化学组分中二次无机盐（SNA）占比高达53．8％，且随着污染加重呈增大趋势；有机碳（OC）／无机碳（EC）比值平均为3．7，二次污染特征显著。分析此次污染成因，一方面是冷空气强度弱及大气静稳等气象条件不利于污染扩散；另一方面本地污染排放叠加区域输送影响，造成细颗粒物积聚增多，形成持续重污染天气。%Using air quality monitoring and meteorological observation datasets,the continuing heavy air pollution characteristics and causes in Nanjing were analyzed during the early December in 201 3.The results showed that the pollution was heavy,long lasting and characterized by a large proportion of fine particulate mat-ter.The highest daily average concentration of PM2.5 was up to 327 μg /m3 with the exceeding rate of 3.36.The chemical composition of SNA proportion was as high as 53.8% and as pollution aggravated,it showed an in-creasing trend.With an average OC /EC ratio of 3.7,the secondary pollution characteristics were significant.In-ferential studies showed that,the pollution was on one hand precipitated by weak cold air intensity and atmos-pheric static stability which were against pollutants diffusion.On the other hand,the cumulated influence of the local pollution and inter-regional transportation caused fine particles to accumulate and form a continuous heavily polluted weather.