Occurrence of atmospheric nitrous acid in the urban area of Beijing (China).
Occurrence of atmospheric nitrous acid in the urban area of Beijing (China).
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DOI：
10.1016/j.scitotenv.2012.12.065
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发表时间：
2013-03
期刊：
影响因子：
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通讯作者：
F. Spataro;A. Ianniello;G. Esposito;I. Allegrini;T. Zhu;Min Hu
中科院分区：
文献类型：
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作者：
F. Spataro;A. Ianniello;G. Esposito;I. Allegrini;T. Zhu;Min Hu
在2007年冬、夏两个季节对北京大气中亚硝酸浓度进行了观测。从时间和日变化以及气象影响的角度对结果进行了讨论。日平均HONO浓度在0.03-2.91ppb之间，冬夏季变化不大。时间趋势似乎主要受气象条件的影响。HONO浓度在冬季和夏季都表现出非常典型的日变化。氮氧化物是HONO形成的关键前体物，HONO/NO2值高于直接排放的值（<1%），表明两个时期直接排放的二次化学HONO形成普遍存在。我们使用了伪稳态方法（PSS），其中包括均相和非均相反应和直接排放，平均约83%和48%的观测到的HONO水平在密集的冬季和夏季期间，分别解释。夏季白天未知的HONO平均产量为2.58ppbh− 1。HNO 3和细颗粒物NO3−光解作为HONO源的贡献较弱。在PSS计算中包括这些源，我们解释了约53%的观测到的HONO水平。结果表明，在夏季观测期间，HONO的来源是气溶胶和地面上依赖于JNO 2的非均匀过程，其中NO2是HONO的前体。
The atmospheric concentrations of nitrous acid (HONO) have been measured during two field campaigns in the winter and summer of 2007 at Beijing (China). The results were discussed from the standpoint of temporal and diurnal variations and meteorological effects. The daily average HONO concentrations were in the range of 0.03–2.91ppb and didn't show temporal variation between the winter and summer periods. The temporal trends seemed to be largely affected by meteorological conditions. HONO concentrations showed very typical diurnal variations during intensive winter and summer periods. Nitrogen oxides were key precursors of HONO formation and the HONO/NO2values were higher than those reported for direct emission (<1%), indicating the prevalence of secondary chemical HONO formation on direct emission during both periods. We used a pseudo steady state approach (PSS), which included homogeneous and heterogeneous reactions and direct emission, explaining on average about 83% and 48% of the observed HONO levels during the intensive winter and summer periods, respectively. The daytime unknown HONO production was on average 2.58ppbh−1during the summer period. The HNO3and fine particulate NO3−photolysis contributed weakly as HONO source. Including these sources in the PSS calculation, we explained about 53% of the observed HONO levels. The results showed that heterogeneous JNO2dependent processes on aerosol and ground surfaces, involving NO2as HONO precursor, were HONO sources during the summer measurements.