Pollution characteristics and potential sources of nitrous acid (HONO) in early autumn 2018 of Beijing
Pollution characteristics and potential sources of nitrous acid (HONO) in early autumn 2018 of Beijing
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DOI：
10.1016/j.scitotenv.2020.139317
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发表时间：
2020-09-15
影响因子：
9.8
通讯作者：
Ge, Maofa
中科院分区：
文献类型：
--
作者：
Jia, Chenhui;Tong, Shengrui;Ge, Maofa
亚硝酸（HONO）是羟基自由基（OH）的重要前体物，对臭氧（O-3）和二次有机气溶胶（SOA）的形成有重要影响。在初秋北京市区进行了大气中HONO浓度的测定。本研究调查了白天和夜间HONO的污染特征和潜在来源。最高小时HONO水平达到5.16 ppb，平均为1.23 ppb。HONO浓度具有典型的日变化特征，夜间最大，白天最小。北京市大气污染的潜在来源主要包括机动车排放、NO2在气溶胶表面的非均相反应（白天为光增强）和颗粒物硝酸盐（NO3-）的光解作用。机动车排放是HONO的重要来源，尤其是在早高峰时段，HONO浓度较低。模拟结果表明，HONO的主要贡献是NO2在气溶胶表面的非均相反应。NO3-的光解也是白天HONO的重要来源，尤其是在污染期间。主要损失途径为HONO的光解和昼夜干沉降。
Nitrous Acid (HONO) is an important precursor of hydroxyl radical (OH) and has significant impacts on the formation of Ozone (O-3) and Secondary Organic Aerosol (SOA). The atmospheric concentrations of HONO were measured during early autumn in downtown, Beijing (China). This study investigated HONO pollution characteristics and potential sources during day and night. The maximum hourly HONO levels reached 5.16 ppb, with 1.23 ppb on average. HONO concentration exhibited typical diurnal variation characteristics, with maximum at nighttime and minimum at daytime. The potential sources mainly included vehicle emission, heterogeneous reaction of NO2 on aerosol surfaces (Photo-enhanced at the daytime) and photolysis of particulate nitrate (NO3-) in Beijing. Vehicle emission was an important HONO source, particular at the morning rush period and lower HONO concentration. The simulated results highlighted that the main contribution of HONO was NO2 heterogeneous reaction on aerosol surfaces. The photolysis of particulate NO3- was also an important daytime HONO source, particularly in the pollution period. The main loss routine was the photolysis of HONO and dry deposition at day and night, respectively.