一种在线测量大气中气态氨和颗粒相铵离子浓度的方法

An On-Line Method of Measuring Gaseous Ammonia and Ammonium in Aerosol in Atmosphere

自主研制了氨检测模块并应用于测量大气中气态氨和大气气溶胶中铵离子。该模块与气体-气溶胶收集系统(GAC)联用,可实现气态氨和铵离子的在线测量。重点介绍了氨检测模块的组成结构和运行流程,以及对氨检测模块的条件测试。该模块已于2006年应用于广州市空气质量的外场观测,观测结果与颗粒物-液体转换采集系统(PILS)测量的数据比对的线性相关系数(R)为0.8207,夜间观测结果的相关系数为0.9703。估计白天温度的波动会对检测模块的测量造成影响。氨检测模块获得的PM2.5中的NH4+浓度是PILS测得的PM10中NH4+的92%,且具有良好的相关性,证实了铵离子主要集中在细粒子PM2.5中。

An ammonium detection module was developed to measure the concentration of ammonia in gas phase and ammonium in aerosols. Connecting with gas ＆ aerosol collector （GAC） system, the module could perform online measurements. This paper introduced the configuration and the running procedure of the module and showed the result of condition experiments. The module was applied to the observation of air quality in Guangzhou and compared with PILS system. The correlation coefficient（ R ） between the module and PILS was 0.820 7. If just night data was analyzed, the coefficient was 0.970 3. Possiblely the measurement was interfered by temperature. The NH^＋4 concentration in PM2.5 which was measured by the module was 92% of that in PM10 which is measured by PILS. It illustrated that ammonium was mainly in fine particles.