Insights into Ammonium Particle-to-Gas Conversion: Non-sulfate Ammonium Coupling with Nitrate and Chloride
Insights into Ammonium Particle-to-Gas Conversion: Non-sulfate Ammonium Coupling with Nitrate and Chloride
复制标题
深入了解铵颗粒到气体的转化：非硫酸铵与硝酸盐和氯化物的偶联
DOI：
10.4209/aaqr.2010.04.0034
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发表时间：
2010-12-01
影响因子：
4
通讯作者：
Ma, Yonglin
中科院分区：
文献类型：
--
作者：
Du, Huanhuan;Kong, Lingdong;Ma, Yonglin
摘要在城市污染空气中发现了大量的氨、硝酸和盐酸作为铵粒子前体。为了进一步了解硝酸铵和氯化铵的形成和解离过程，采用在线气溶胶和环境空气气体监测分析仪，以1小时分辨率测量了气溶胶中硫酸盐、硝酸盐和氯化物以及相关气体前体的浓度。2009年6月12日至14日，上海PM10中硫酸盐、硝酸盐、氯化物和铵的总小时平均值最高达177.7 μg/m3, 7月1日至3日，PM2.5最高达101.2 μg/m3。硝酸铵和氯化铵在气溶胶中普遍存在，非硫酸盐铵（ns-NH4+）与硝酸盐（或硝酸盐加氯化物）之间存在很强的线性相关性。由于气溶胶的贫铵性，铵的当量浓度始终小于硫酸盐、硝酸盐和氯化物的总和，而大气在气相中是富铵的。在PM10和PM2.5中，气态硝酸与总硝酸盐的比值小于盐酸与总氯的比值，说明硝酸铵比氯化铵更容易形成。
ABSTRACTSignificant amounts of ammonia, nitric acid and hydrochloric acid as ammonium particle precursors have been found in urban polluted air. In order to advance understanding the formation and dissociation of ammonium nitrate and ammonium chloride, an on-line analyzer for monitoring aerosols and gases in the ambient air was employed to measure the concentrations of sulfate, nitrate and chloride in aerosols as well as related gaseous precursors at one hour resolution. The highest levels of summed hourly-averaged sulfate, nitrate, chloride and ammonium reached up to 177.7 μg/m3 in PM10 from 12 to 14 June, and 101.2 μg/m3 in PM2.5 from 1 to 3 July, 2009 in Shanghai. Ammonium nitrate and ammonium chloride were popular in aerosols with a strong linear correlation between non-sulfate ammonium (ns-NH4+) and nitrate (or nitrate plus chloride). Ammonium equivalent concentration was always less than the sum of sulfate, nitrate and chloride due to ammonium-poor aerosols, whereas the atmosphere was ammonia-rich in gas phase. The ratio of gaseous nitric acid to total nitrate less than that of hydrochloric acid to total chloride both in PM10 and PM2.5 indicated that ammonium nitrate was more favored to be formed than ammonium chloride.