Physical and chemical characterization of urban grime: An impact on the NO2 uptake coefficients and N-containing product compounds.
Physical and chemical characterization of urban grime: An impact on the NO2 uptake coefficients and N-containing product compounds.
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城市污垢的物理和化学特征：对 NO2 吸收系数和含氮产物化合物的影响。
DOI：
10.1016/j.scitotenv.2022.155973
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
S. Gligorovski
中科院分区：
文献类型：
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作者：
Jiangping Liu;Huifan Deng;Runqi Zhang;Wei Song;Xue Li;Yongming Luo;Xinming Wang;S. Gligorovski
城市污垢是城市环境中异质反应的重要环境表面。在这里，我们评估了连续6个月在广州市中心收集的城市灰尘的物理和化学性质，中国。城市灰尘对NO2的吸收系数随相对湿度(RH)的变化有很大差异。在没有水分子(0%RH)的情况下，6个月采集的城市污垢样品对NO2的光诱导吸收系数的大小顺序为≈10−6。在RH为80%时，不同采样月份NO2的光诱导吸收系数可达到比0%RH时高一个数量级(1.5×10−5，RH为80%)。在RH浓度为80%时，测定的NO2吸入量与城市灰尘中的水溶性碳、可溶性阴离子、多环芳烃和正构烷烃的浓度之间存在很强的相关性。这些相关性表明，城市污垢表面吸附的水对NO2的吸收起着重要的作用。在相对湿度为60%的太阳光照射下(68W m−2，30 0 nm<；λ<；4 0 0 nm)，NO2在2个月龄的城市尘埃上的异相转化导致了前所未有的4.7×10 10分子cm−2s−1的HONO面通量，高于所有观测到的HONO通量，从而影响了城市大气的氧化能力。在NO2与城市烟尘的非均相化学过程中，气相中释放出不饱和的含氮有机物，影响城市环境的空气质量。
Urban grime represents an important environmental surface for heterogeneous reactions in urban environment. Here, we assess the physical and chemical properties of urban grime collected during six consecutive months in downtown of Guangzhou, China. There is a significant variation of the uptake coefficients of NO2on the urban grime as a function of the relative humidity (RH). In absence of water molecules (0% RH), the light-induced uptake coefficients of NO2on urban grime samples collected during six months are very similar in order of ≈10−6. At 80% RH, depending on the sampling month the light-induced uptake coefficient of NO2can reach one order of magnitude higher values (1.5 × 10−5, at 80% RH) compared to those uptakes at 0% RH. In presence of 80% RH, there are strong correlations between the measured NO2uptakes and the concentrations of the water soluble carbon, soluble anions, polycyclic aromatic hydrocarbons and n-alkanes depicted in the urban grime. These correlations, demonstrate that surface adsorbed water on urban grime play an important role for the uptakes of NO2. The heterogeneous conversion of NO2on two-month old urban grime under sunlight irradiation (68 W m−2, 300 nm < λ < 400 nm) at 60% RH leads to the formation of unprecedented HONO surface flux of 4.7 × 1010molecules cm−2s−1which is higher than all previously observed HONO fluxes, thereby affecting the oxidation capacity of the urban atmosphere. During the heterogeneous chemistry of NO2with urban grime, the unsaturated and N-containing organic compounds are released in the gas phase which can affect the air quality in the urban environment.