西安地区夏季臭氧的模拟研究  

Simulations of summertime ozone in Xi'an and surrounding areas

作　　者：贝耐芳[1] 冯添[2] 吴佳睿 李国辉[2,3] 

机构地区：[1]西安交通大学人居环境与建筑工程学院,西安710054 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710061 [3]中国科学院气溶胶化学与物理重点实验室,西安710061

出　　处：《地球环境学报》2017年第6期552-567,共16页Journal of Earth Environment

基　　金：国家自然科学基金项目(41275101;41275153;41430424);中央高校基本科研业务费专项资金(2013jdhz25;zdyf2017001)~~

摘　　要：本文利用WRF-CHEM模式对关中地区2015年7月25日至30日的一次O_3污染事件进行了数值模拟。通过与地面观测数据对比发现,WRF-CHEM模式基本上可以合理模拟西安和咸阳城市群O_3和NO_2的质量浓度的时空分布。敏感性试验表明,在臭氧生成的峰值期(12:00—18:00 LT),交通源是城市重要的O_3源,无论在高浓度臭氧条件下还是低浓度臭氧条件下,贡献量都高于15μg?m^(-3),平均贡献量均高于24μg?m^(-3);工业源仅在臭氧峰值生成时期贡献明显;生物源无论在高浓度还是低浓度臭氧的条件下,平均贡献都在16μg?m^(-3)以上;居民源的贡献基本低于10μg?m^(-3);能源生产源有降低O_3质量浓度的作用,但在臭氧生成的峰值时期,能源生产源可以增加O_3质量浓度。随着交通源排放量的增加,O_3的质量浓度逐渐增加,尤其在臭氧的峰值期。在臭氧生成峰值期,当氮氧化物(NOx)减少50%时,除城市中心臭氧浓度略增加,其他地区臭氧质量浓度均在下降;当挥发性有机物(VOCs)减少50%时,城市群内臭氧质量浓度都在下降;当NO_x和VOCs同时减少50%时,臭氧质量浓度都呈现下降趋势,减少量可达20μg?m^(-3)以上。在整个研究区域内,H_2O_2/HNO_3比值均在0.6以上,这表明西安和咸阳城市群属于NO_x控制区。Background, aim, and scope Ozone （O3） is a key species in the atmosphere due to its role in controlling the photochemistry in the stratosphere and troposphere since O3 and its photochemical derivative, OH, are the major oxidants for most reduced gases. High levels of surface O3 exert deleterious impacts on ecosystems and human health and O3 is one of the criteria pollutants regulated by the environmental agencies in many countries, such as the US Environmental Protection Agency （US EPA） and China’s Ministry of Environmental Protection （China MEP）. The objective of this study is to simulate summertime O3 concentration in Xi’an and its surrounding areas and examine the main infuence factors and precursor contributors. Materials and methods We simulate an O3 pollution event during the period from 25 to 30 July 2015 in the Guanzhong region, China using the WRF-CHEM model. Statistics including mean bias, root mean square error, and index of agreement is used to evaluate the model performance. Results Compared with the ground-based measurements, the model generally reasonably reproduces the spatiotemporal patterns of O3 and NO2 concentrations over the city clusters including Xi’an and Xianyang. Sensitivity studies show that transportation emission contributes the most to urban O3 levels during peak episodes （12：00 - 18：00 LT） and the contribution is higher than 15 μg ·m-3 during both high- and low-level O3 episodes with an average of 〉24 μg · m-3; biological emission contributes 〉16 μg ·m-3 during both high- and low-level O3 episodes; the contribution from industrial emission is remarkable only at O3 peak time; the contribution from residential sources is 〈10 μg · m-3. Discussion The emissions from power plants generally suppress O3 production but enhance O3 formation during peak periods. O3 concentration is increased along with the increasing emission from transportation, particularly at O3 peak time. If the emitted nitrogen oxides（NOx） were reduced by 50%, in general,

关 键 词：O3 NOx WRF-CHEM 西安 

分 类 号：X515[环境科学与工程—环境工程]