基于随机森林模型评估冬奥会期间太原市大气氨的气象和排放影响  

Assessing Impacts of the 2022 Winter Olympic Games on Meteorology and of Atmospheric Ammonia Emissions in Taiyuan City Using a Random Forest Model

作　　者：任明权 崔阳 郭利利 何秋生 吉东生[3] 王跃思[3] REN Mingquan;CUI Yang;GUO Lili;HE Qiusheng;JI Dongsheng;WANG Yuesi(School of Environment and Resources,Taiyuan University of Science and Technology,Taiyuan 030024,China;Shanxi Polytechnic College,Department of Materials Environmental Engineering,Taiyuan 030006,China;State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beiing 100029,China)

机构地区：[1]太原科技大学环境与资源学院,太原030024 [2]山西职业技术学院材料环境工程系,太原030006 [3]中国科学院大气物理研究所大气边界层物理和大气化学国家重点实验室,北京100029

出　　处：《地球与环境》2025年第1期64-73,共10页Earth and Environment

基　　金：国家重点研发计划资助(2023YFC3709500);国家自然科学基金项目(42077201、22076135);太原市细颗粒物和臭氧污染协同防控“一市一策”驻点跟踪研究项目(DQGG202107);山西省基础研究计划项目(202103021223300);山西省研究生优秀创新项目(2022Y687、2021Y686)。

摘　　要：为保障第24届冬季奥林匹克运动会期间(2022年2月4日至20日)的空气质量,太原市实施了一系列人为管控(机动车限行和工业企业减产)措施。为评估短期控制措施对城市大气NH_(3)的影响,本研究使用MARGA仪器于2022年1月1日至2月20日期间在太原市一城市站点对小时分辨率的气态NH_(3)及水溶性离子进行了在线观测,分析了其污染特征并采用随机森林模型评估了气象和排放的影响。研究结果表明冬奥会管控期C2(1月30日至2月20日)NH_(3)浓度(5.4±3.3μg/m^(3))低于管控前时段C1(1月1日至1月29日;8.4±3.9μg/m^(3))36.0%。与C1期间相比,C2期间更高的风速(1.8±0.8 m/s)和大气边界层高度(508.1±636.7 m)有利于污染物扩散,而C2期间酸性气体NO_(2)(47.8%)和SO_(2)浓度(33.2%)的显著降低会通过气相分配提升NH_(3)浓度,表明气象和化学因素会干扰排放变化对NH_(3)影响评估。随机森林模型分析结果显示C2期间NH_(3)、NH_(4)^(+)和TNHx(NH_(3)+NH_(4)^(+))气象归一化浓度较C1时期分别下降25.2%、21.3%和20.3%。TNHx由于综合考虑人为排放和二次转化的影响能更好地反映人为排放造成NH_(3)的真实变化。C2期间人为减排和气象因素对TNHx下降的贡献分别为39.5%和60.5%,表明在有利的气象条件影响下人为减排进一步降低了TNHx浓度。研究结果可为其他区域评估管控措施对环境空气质量的影响提供一定的科学参考。To ensure improvement of air quality during the 24th Winter Olympic Games(Beijing 2022),held from 4th to 20th February 2022,a series of anthropogenic control measures(motor vehicle restrictions and industrial production curbs)were implemented in Taiyuan city.In order to assess the impacts of the short-term control measures on urban atmospheric ammonia(NH_(3)),online observations of hourlyresolved gaseous NH_(3)and water-soluble ions were monitored using MARGA at an urban site in Taiyuan city from 1 January to 20th February,2022.The pollution was characterized and,in parallel,the influence on meteorology and NH_(3)emissions were assessed using a random forest model.The results showed that the NH_(3)concentration(5.4±3.3μg/m^(3))during the control period of the Winter Olympic Games(C2:30th January to 20th February)was 36.0%lower than the pre-control period(C1:1st to 29th January;8.4±3.9μg/m^(3)).Compared with the C1 period,higher wind speed(1.8±0.8 m/s)and the atmospheric boundary layer height(508.1±636.7 m)favored pollutant dispersion during the C2 period,whereas obvious decline in acidic gas concentrations(NO_(2),47.8%,and SO_(2),33.2%)during the C2 period could have elevated NH_(3)concentration through gas-particle partitioning of NH_(3),suggesting that meteorological and chemical factors could have interfered with the assessment of NH_(3)impact from emission changes.The results of the random forest model showed that meteorological normalized concentrations of NH_(3),NH_(4)^(+)and TNHx(NH_(3)+NH_(4)^(+))decreased by 25.2%,21.3%and 20.3%during C2,respectively,compared with C1.Due to the combination of the effects of anthropogenic emissions and secondary conversion,TNHx could better assess the real changes of NH_(3)caused by anthropogenic emissions.The contributions of anthropogenic emission reduction and meteorological factors to the decrease in TNHx during C2 were 39.5%and 60.5%,respectively,indicating that the reduction of anthropogenic emissions further lowered TNHx concentration under favorable meteorol

关 键 词：氨气 气粒转化 随机森林模型 冬奥会 

分 类 号：X51[环境科学与工程—环境工程]