摘要
国内外针对沙漠地区臭氧浓度演变特征研究存在较大空白。阿拉善左旗属于我国西部典型的荒漠城市,在人为活动强度较低的情况下,具有较高的臭氧(O_(3))背景浓度。2015~2022年O_(3)浓度日最大8 h平均值(MDA8 O_(3))年增长约为2μg m^(−3),春、夏、秋、冬季节平均MDA8 O_(3)分别为111.3μg m^(−3)、132.3μg m^(−3)、101.8μg m^(−3)和82.9μg m^(−3)。由于高温强辐射的有利条件促进O_(3)的大气光化学反应,增强O_(3)的二次生成,因此O_(3)污染主要出现于夏季。夏季夜间在NO滴定效应影响下,阿拉善左旗各监测站O_(3)浓度仍然可以达到93~106μg m^(−3),且观测站点距地面越高,O_(3)浓度越高,表明西部沙漠地区受到高O_(3)背景浓度控制。观测发现近地面人为排放对三个距离地面不同高度站点的O_(3)浓度产生不同的影响。以距地面22 m的环保局新楼站O_(3)浓度为参考,距地面15 m的蒙二幼站夜间O_(3)浓度低5~25μg m^(−3),日间O_(3)浓度高5μg m^(−3);距地面12 m西花园站站点夜间O_(3)浓度低10~25μg m^(−3),日间O_(3)浓度高5μg m^(−3)。对于城区夜晚越靠近地面NO滴定效应越强,白天随着对流扩散和近地面快速的O_(3)光化学反应影响,越靠近地面O_(3)浓度越高,说明弱人为活动对O_(3)浓度的影响,反映沙漠城市O_(3)垂直分布特征。
There are large gaps in the domestic and international research on the characteristics of ozone(O_(3))concentration evolution in desert areas.Alxa Left Banner is a typical desert city in western China;it has high background O_(3)concentrations because of the low intensity of anthropogenic activities.From 2015 to 2022,the annual growth of daily maximum 8-h average ozone(MDA8 O_(3))was approximately 2μg m^(−3).The average MDA8 O_(3)values in spring,summer,autumn,and winter were 111.3μg m^(−3),132.3μg m^(−3),101.8μg m^(−3),and 82.9μg m^(−3),respectively.The existence of favorable conditions,namely,high temperature and strong radiation,promotes the atmospheric photochemical reaction of O_(3)and enhances the secondary production of O_(3);therefore,O_(3)pollution incidents mainly occur in the summer.The O_(3)concentrations in Alashan Left Banner were 93–106μg m^(−3)on summer nights under the influence of the NO titration effect,indicating that this region featured a high background O_(3)level.The greater the distance from the observation point to the ground,the higher the O_(3)concentration.The observations showed that the near-surface anthropogenic emissions have a direct and significant influence on the vertical O_(3)concentrations at three stations(Huanbaojuxinlou,Mengeryou,and Xihuayuan stations)with different heights over the ground surface.The O_(3)concentration at Huanbaojuxinlou station(22 m above the ground)was set as a criterion.The O_(3)concentration at Mengeryou station,15 m above the ground,was lower by 5–25μg m^(−3)during the night and higher by 5μg m^(−3)at noon.The O_(3)concentration at Xihuayuan station,12 m above the ground,was lower by 10–25μg m^(−3)during the night and higher by 5μg m^(−3)at noon.A strong NO titration effect was observed in the near-ground atmosphere in the urban areas at night.However,high O_(3)concentrations were observed in the near-ground atmosphere because of convective diffusion and rapid photochemical reactions.Thus,the weak effect of human activities on O_(3)concentration was illustrated,and the vertical distribution characteristics of O_(3)in desert cities were captured.
作者
张少亭
吴八一
王芳
武红
任鑫冰
马永敬
吴方堃
孙扬
周兴军
田永莉
辛金元
ZHANG Shaoting;WU Bayi;WANG Fang;WU Hong;REN Xinbing;MA Yongjing;WU Fangkun;SUN Yang;ZHOU Xingjun;TIAN Yongli;XIN Jinyuan(State Key Laboratory of Atmospheric Environment and Extreme Meteorology,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;Alashan Substation,Inner Mongolia Environmental Monitoring Center Station,Alax Left Banner 750300;Inner Mongolia Environmental Monitoring Center Station,Hohhot 010011;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049)
出处
《大气科学》
北大核心
2025年第6期1663-1674,共12页
Chinese Journal of Atmospheric Sciences
基金
国家重点研发计划项目2022YFF0802501
内蒙古自治区科技计划项目2021GG0100。
关键词
臭氧污染
滴定效应
光化学过程
西部荒漠
阿拉善左旗
Ozone pollution
Titration effect
Photochemical processes
Western desert
Alxa Left Banner
