亚硝酸
化学
亚硝酸盐
相对湿度
亚硫酸盐
二氧化氮
氨
微量气体
反应性(心理学)
二氧化硫
羟基自由基
氧化还原
环境化学
无机化学
激进的
气象学
硝酸盐
有机化学
病理
替代医学
物理
医学
作者
Qingxia Ma,Tao Wang,Chang Liu,Hong He,Zhe Wang,Weihao Wang,Yutong Liang
标识
DOI:10.1021/acs.est.6b05724
摘要
Nitrous acid (HONO) is an important source of hydroxyl radical (OH) that determines the fate of many chemically active and climate relevant trace gases. However, the sources and the formation mechanisms of HONO remain poorly understood. In this study, the effect of SO2 on the heterogeneous reactions of NO2 on MgO as a mineral dust surrogate was investigated. The reactivity of MgO to NO2 is weak, while coexisting SO2 can increase the uptake coefficients of NO2 on MgO by 2-3 orders of magnitude. The uptake coefficients of NO2 on SO2-aged MgO are independent of NO2 concentrations in the range of 20-160 ppbv and relative humidity (0-70%RH). The reaction mechanism was demonstrated to be a redox reaction between NO2 and surface sulfite. In the presence of SO2, NO2 was reduced to nitrite under dry conditions, which could be further converted to gas-phase HONO in humid conditions. These results suggest that the reductive effect of SO2 on the heterogeneous conversion of NO2 to HONO may have a significant contribution to the unknown sources of HONO observed in polluted areas (for example, in China).
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