霾天气南京市大气PM_(2.5)中水溶性离子污染特征

为了讨论南京市大气细颗粒物(PM2.5)及水溶性组分在霾天气下的污染水平和污染特征,2007年6月10日至2008年5月29日对南京市大气细粒子PM2.5进行了采样,用PM2.5在线监测浓度、离子色谱法等分别测得PM2.5的质量浓度、水溶性离子组成,初步研究了南京市大气细粒子(PM2.5)及水溶性组分在霾天气下的污染水平和污染特征。结果表明,南京市大气细颗粒物污染严重,霾天气下PM2.5中总水溶性离子质量浓度为54.28μg/m3,为非霾天气的1.6倍。分析的6种离子中SO42-、NO3-、NH4+是PM2.5的主要组成成分。灰霾期间PM2.5与NO3-、SO42-、NH4+的相关性较高,PM2.5中颗粒物的主要存在形式可能为NH4Cl、NH4NO3,(NH)42SO4或NH4HSO4。对比不同季节不同天气下的SOR(SO2转化率)和NOR(NOx转化率),发现霾天气下SO2和NOX转化率高于正常天气,表明SO2、NO2在霾天气更容易转化为二次粒子。

Pollution Characteristics of Nanjing Water-soluble Ions in Air Fine Particles under Haze Days

To discuss the pollution level and pollution characteristics of Nanjing air fine particles (PM2.5)and water-soluble ions under haze days,PM2.5 was sampled during June 10,2007 to May 29,2008 in Nanjing. The concentration of PM2.5 was monitored online,and the quality concentration of PM2.5 was monitored by ions chromatography. Results showed that the fine particles pollution was severe,total water-soluble ions quality concentration of PM2.5 under haze days was 54.28μg/m3,1.6 times than that under non-haze days. SO42-,NO3and NH4+ are main components in the analyzed 6 ions. During haze days, PM2.5 and NO3-,SO42has strong relativity. The fine particles in PM2.5 exists likely in the form of NH4Cl,NH4NO3,(NH4)2SO4 or NH4HSO4. Compared SO2 conversion rate and NOx conversion rate under different seasons and different weather,SO2 conversion rate and NOx conversion rate in haze days was found higher than that in normal days,which showed SO2 and NO2 under haze days was easier to convert secondary particles.