摘要
HONO作为羟基自由基(·OH)的主要前体物而受到广泛关注,近几十年开展了大量观测,但高空观测较为稀缺,尤其在珠三角地区尚未开展.本研究于2020年8月在广州塔450m平台开展了HONO及相关参数的测量,结果表明:450m高空HONO平均浓度为(1.32±0.63)μg·m^(-3),呈日间低、夜间高的日变化特征.日间地面相关来源(机动车排放、NO_(2)非均相转化)在传输过程中光解损耗,约有56%到达高空.此外,均相反应、气溶胶表面的非均相转化、硝酸盐光解等原位反应也都无法解释观测到的HONO浓度.因此,还需要其他来源来平衡HONO收支.高空450 m处HONO对·OH的贡献在上午远大于O_(3),对光化学过程的启动具有重要作用,在全天对·OH的贡献也与O_(3)相当.可见,城市地区HONO对大气氧化性的影响不局限于地面,而可能贯穿下半个边界层.
Nitrous acid(HONO)has attracted widespread attention as a major precursor of atmospheric OH radicals,with numerous field observations conducted in the past several decades.However,high-altitude observations remain scarce,especially in the Pearl River Delta region.This study conducted measurements of HONO and affiliated parameters at the 450 m platform of the Canton Tower in August 2020.The results showed that the average concentration of HONO at 450 m was(1.32±0.63)μg·m^(-3),which showed the diurnal pattern of low concentrations during the daytime and high concentrations during nighttime.During the daytime,ground-related sources(i.e.vehicle emissions,heterogeneous conversion of NO_(2) on ground surface)underwent a loss due to photolysis during upward transmission,with an average of 56%reaching the 450 m platform.In addition,in-situ reactions,such as homogeneous reaction,heterogeneous conversion on aerosol surfaces and photolysis of nitrate were unable to explain the observed HONO concentrations.Therefore,another unknown source is required to balance the HONO budget.The contribution of HONO to·OH during the morning was significantly higher than that of O_(3) at 450 m,initiating daytime photochemical processes,while comparable with O_(3) throughout the day.These findings suggest that of the impact of HONO on atmospheric oxidizing capacity in urban areas is not limited to the surface but may extend throughout the lower boundary layer.
作者
龚育诚
程鹏
杨闻达
韩宝彬
余毅航
李小兵
袁斌
裴成磊
沈劲
GONG Yucheng;CHENG Peng;YANG Wenda;HAN Baobin;YU Yihang;LI Xiaobing;YUAN Bin;PEI Chenglei;SHEN Jin(Institute of Mass Spectrometer and Atmospheric Environment,Jinan University,Guangzhou 510632;Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution,Jinan University,Guangzhou 510632;Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation for Environmental Quality,Guangzhou 511443;Institute for Environmental and Climate Research,Jinan University,Guangzhou 511443;Guangzhou Ecological and Environmental Monitoring Center of Guangdong Province,Guangzhou 510006;Guangdong Environmental Monitoring Center,Guangzhou 510308)
出处
《环境科学学报》
CAS
CSCD
北大核心
2024年第2期330-342,共13页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.42121004)
国家重点研发计划项目(No.2017YFC0210104,2018YFC0213904)。
