中国西部人为源NO2污染的时空分布及影响因素研究

利用臭氧监测仪卫星遥感反演获得对流层NO_2柱浓度数据,分析了2005—2016年中国西部地区NO_2污染的时空演变特征及影响因素.首先,根据NO_2污染的季节特性,剔除了自然源NO_2后得到人为源NO_2柱浓度信息;然后,利用小波变换分解方法对西部地区NO_2柱浓度的长期趋势和季节特性进行提取,并对比了东西部的NO_2增长情况;最后,结合经济社会数据分析了西部各省NO_2污染的主要驱动因素.结果发现,西部地区的NO_2浓度在2005—2012年期间呈快速增长趋势,西北各省份的增速均超过了10%a~(-1).然而,2012年之后,西部各省的NO_2浓度开始下降.结合"十二五"计划中的各省氮氧化物减排目标,发现大多数西部省份都较好地完成了减排任务.此外,煤炭消费是西部各省NO_2污染的最主要因素.然而,对于云南和四川而言,虽然水电发展替代了部分火电,使得煤炭消费增速减缓,但交通排放成为这两个省份NO_2污染的最主要驱动因素.西部地区是国家"一带一路"新战略的重要区域,本研究结果将为政府制定有效的控制排放政策,以及促进西部区域可持续发展提供重要的科学参考.

Spatio-temporal variations and influential factors of anthropogenic NO2 pollution over Western China

Using the tropospheric NO₂ columns observed by the satellite-based Ozone Monitoring Instrument (OMI), we analyzed the spatio-temporal variations and influential factors of NO₂ pollution over Western China from 2005 to 2016. First, the anthropogenic NO₂ columns were estimated dependent on the seasonal characteristics of NO₂ pollution, excluding the source of natural NO₂. The long-term trend and seasonal characteristics of NO₂ columns over Western China were then extracted by the wavelet transform method. We compared the changes of NO₂ columns over Western China and Eastern China. Finally, combined with economic and social data, the main drivers of NO₂ pollution over Western China were analyzed. The results showed that the NO₂ columns over Western China showed a rapidly increasing trend from 2005 to 2012. Specifically, the growth rate of northwestern provinces exceeded 10% a^-1. After 2012, the NO₂ columns over Western China began to decrease. We observed that most western provinces had completed the emission reduction targets of the "12^th Five-Year Plan". In addition, coal consumption is the most important factor of NO₂ pollution. Although part of thermal power in Yunnan and Sichuan Provinces has been replaced with hydropower and the growth rate of coal consumption has slowed down, traffic emissions have already become the main source of local NO₂ pollution in the two provinces. As one of the key regions of the national "One Belt, One Road Initiative" new strategy, the results of this study will provide an important scientific basis for the Chinese government to formulate effective emission control policies and promote regional balance and sustainable development.