摘要
基于太原市2013年5、6、12月和2014年1月大气中SO_2、NO_2及PM_(2.5)中水溶性离子SO_4^(2-)、NO_3^-浓度,分析了大气中硫和氮的转化率(Fs、Fn),并探讨了其影响因素.结果表明,大气中SO_2、NO_2的浓度夏季(5、6月)分别为89.98、64.73μg·m-3,由于燃煤供热冬季(12、1月)SO_2显著升高,SO_2和NO_2分别为119.09、63.92μg·m-3.PM_(2.5)中水溶性离子SO_4^(2-)、NO_3^-夏季分别为16.54、6.87μg·m-3,冬季显著降低,分别为12.79、5.53μg·m-3.参照硫和氮气固两相转化模型,Fs夏季(0.13)高于冬季(0.07),Fn变化较小,夏、冬季分别为0.08、0.06,与南方城市相比,Fs较高,Fn较低.硫、氮转化受多种因素共同影响,且不同季节主导因素不同.温度和O_3浓度对整个采样期间的硫转化起主要作用,冬季SO_4^(2-)与PM_(2.5)和湿度呈现一定的相关关系,显示SO_4^(2-)主要来源于均相气相反应,冬季部分源于非均相反应.夏季相对湿度和O_3浓度可明显促进氮转化,而冬季NO_3^-生成还与PM_(2.5)和温度有关,说明夏季氮转化以均相液相反应为主,而冬季NO_3^-主要源于非均相反应.此外,NH+4与SO_4^(2-)、NO_3^-的线性分析表明,大气氨有助于气相中的硫、氮向颗粒相转移并转化.
The conversion ratios of sulfur and nitrogen（ Fsand Fn） from air to particle in Taiyuan were discussed,based on the atmospheric SO2 and NO2and the water soluble ions（ SO4（2-）and NO3-）in PM（2.5）during two period of May—June 2013（ summer） and December 2013—January 2014（ winter）.As the results showed,the SO2 and NO2 contents in summer were 89. 98 μg·m-3and64.73 μg·m-3,respectively,while in winter NO2 level was constant,but SO2 increased to 119. 09μg·m-3due to higher coal combustion for heating. The SO4（2-）and NO3-levels in PM（2.5）were 16.54 and6.87 μg·m-3in summer,and decreased to 12.79 μg·m-3and 5.53 μg·m-3in winter,respectively.By using the modified forms of the gas-particle distribution,Fsand Fnwere 0. 13 and 0. 08 in summer,and 0.07 and 0.06 in winter,respectively. Both Fsand Fnwere affected by multiple factorssimultaneously,and the main factors varied seasonally. Higher temperature and ozone（ O3） level contributed primarily to higher sulfur conversion, showing that SO4（2-）mainly came from the homogeneous gas-phase reaction. However SO4（2-）partially came from heterogeneous reactions in the winter because of a correlation between SO4（2-）,PM（2.5）and relative humidity（ RH,%）. Fnincreased with relative humidity and O3 level in the summer,but in the winter NO3-was partially affected by temperature and PM（2.5）level. These indicated the homogeneous liquid-phase reaction played an important role in the process of nitrogen conversion in summer,but the heterogeneous reaction dominated in winter. Furthermore,NH4＋ in PM（2.5）was well correlated with SO4（2-）and NO3-,which indicated atmospheric NH3 may enhance the gas to particle sulfur and nitrogen migration and conversion.
出处
《环境化学》
CAS
CSCD
北大核心
2016年第1期11-17,共7页
Environmental Chemistry
基金
国家自然基金(41172316)
国家教育部重点项目(211026)
山西省青年科技研究基金(2011021025-2)
山西省回国留学人员科研项目(2011080)资助~~
关键词
太原
硫酸盐
硝酸盐
气象因素
转化率
气溶胶
Taiyuan
sulfate
nitrate
meteorological factors
conversion ratio
aerosol
