研究论文
宿文康,鲍晓磊,孟琛琛,倪爽英.冬季PM2.5中无机水溶性离子与大气相对湿度的相关性[J].环境科学学报,2021,41(5):1734-1740
冬季PM2.5中无机水溶性离子与大气相对湿度的相关性
- Correlation analysis on inorganic water soluble ions in PM2.5 and relative humidity of atmosphere in winter
- 基金项目：国家重点研发计划课题（No.2017YFC0213006）；国家重点研发计划课题（No.2017YFC0213002）
- 作者
- 单位
- 宿文康
- 河北省生态环境科学研究院, 石家庄 050037
- 鲍晓磊
- 河北省生态环境科学研究院, 石家庄 050037
- 孟琛琛
- 河北省生态环境科学研究院, 石家庄 050037
- 倪爽英
- 河北省生态环境科学研究院, 石家庄 050037
- 摘要：依托河北省灰霾污染防治重点实验室，对2019年11月26日—12月31日石家庄市大气PM2.5中的NO3-和SO42-进行连续在线观测，研究NO3-和SO42-与环境空气相对湿度的相关性，解析冬季发生PM2.5重污染天气的RH阈值.观测期间，RH为10%~60%时，NO3-的浓度与RH呈显著正相关，为PM2.5中浓度最高的无机水溶性离子.RH超过70%后，NO3-与RH呈负相关，NO3-浓度和NOR开始下降.SO42-浓度与RH在整个湿度区间均呈正相关.RH低于50%时，SO2向SO42-的转化以气相反应为主.RH高于50%以后，颗粒物达到潮解点，SO2的主要反应转入液相，转化速率加快，SO2液相反应贡献逐渐增加至64.6%.RH超过70%后，SO42-成为PM2.5中浓度最高的无机水溶性离子.RH超过PM2.5潮解点以后，NO3-和SO42-大量合成，推高PM2.5环境浓度，易于形成重污染天气.
- Abstract：The mass concentration of NO3- and SO42- in PM2.5 was continuously observed on-line from November 26 to December 31, 2019 at Hebei Key Laboratory of Haze Pollution Prevention and Control in Shijiazhuang. The quantitative relationship between the relative humidity (RH) of ambient air and the concentration of NO3- and SO42- was analyzed, and the RH threshold of heavy pollution of PM2.5 in winter was determined. When RH was in the range of 10%~60%, NO3- was the most abundant inorganic water-soluble ion in PM2.5, and the concentration of NO3- was significantly positively related to RH. When RH was over 70%, NO3- was negatively correlated with RH. The concentration of SO42- was positively correlated with RH in the whole humidity range. When RH was below 50%, the transformation from SO2 to SO42- was dominated by gas phase reaction route. When RH exceeded 50%, the particles reached the deliquescence point, which made the main reaction route of SO2 transferring to liquid phase, and the reaction rate was accelerated. The contribution of liquid phase reaction to SO42- formation was gradually increased to 64.6%. When RH was over 70%, SO42- became the most abundant inorganic water-soluble ion in PM2.5. When RH exceeded the deliquescence point of PM2.5, NO3- and SO42- formation were enhanced, increasing the concentration of PM2.5 to the heavy pollution level.
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