三明市大气PM_(2.5)浓度及3种水溶性阴离子组成特征

Concentration of PM_(2.5) and the composition of three kinds of water-soluble anions in atmosphere in Sanming City

目的了解三明市不同周边环境大气中PM_(2.5)浓度及3种水溶性阴离子SO_4^(2-)、NO_3^-、Cl^-的浓度。方法选择A(周围有居民区、工厂、建筑工地及铁路、公路)、B(周围主要为居民区)两个采样点,2015年每月10~16日每天采样20h。用中流量采样器采样,重量法检测PM_(2.5)浓度,离子色谱法检测SO_4^(2-)、NO_3^-和Cl^-水溶性阴离子浓度。结果采样期间,A、B两点的大气中PM_(2.5)浓度均值分别为67.0μg/m^3与59.8μg/m^3,且冬季>秋季>春季>夏季;SO_4^(2-)、NO_3^-、Cl^-水溶性阴离子浓度均值分别为9.98、4.04、0.34μg/m^3。结论 SO_4^(2-)、NO_3^-、Cl-是采样点大气中PM_(2.5)的重要组成成分。NO_3^-与SO_4^(2-)浓度有相关性,NO_3^-/SO_4^(2-)的比值为0.41,说明采样点大气中PM_(2.5)主要来自固定排放源(燃煤)。

Objective To investigate the concentration of PM2.5 and three kinds of water-soluble anionsSO42- ,NO3- ,Cl-） in atmosphere of different environments in Sanming City. Methods Two sampling sites,A（surrounded by residential areas, factories, construction sites and railways and roads）and B（around residential areas mainly）were selected and the air samples were detected from the 10th to the 16th per month for 20 hours/day in 2015.Sampling with medium flow sampler,PM2.5 concentration was detected by gravimetric method and concentrations of three kinds of anions were detected by ion chromatography. Results During the sampling days,mean concentrations of PM2.5 in atmosphereat A and B were 67.0 μg/m3 and 59.8μg/m3 respectively, and winter〉 autumn〉 spring〉 summer. The mean concentrations of the three kinds of anions were 9.98,4.04,0.34μg/m3. Conclusion SO42- ,NO3- and Cl are important components of PM2.5 at sampling sites.NO3- concentrations are correlated with SO42- concentrations, and the ratio of NO3-/SO4 2- is 0.41. It has been proved that PM2.5 in atmosphere is mainly from stationary sources（coal combustion）.