Song Yifei, Zhang Yuanyuan, Liu Junfeng, Zhang Chenglong, Liu Chengtang, Liu Pengfei, Mu Yujing
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Environ Sci (China). 2022 Apr;114:126-135. doi: 10.1016/j.jes.2021.08.015. Epub 2022 Jan 15.
Tropospheric ozone (O) pollution is increasing in the Beijing-Tianjin-Hebei (BTH) region despite a significant decline in atmospheric fine aerosol particles (PM) in recent years. However, the intrinsic reason for the elevation of the regional O is still unclear. In this study, we analyzed the spatio-temporal variations of tropospheric O and relevant pollutants (PM, NO, and CO) in the BTH region based on monitoring data from the China Ministry of Ecology and Environment during the period of 2014-2019. The results showed that summertime O concentrations were constant in Beijing (BJ, 0.06 µg/(m•year)) but increased significantly in Tianjin (TJ, 9.09 µg/(m•year)) and Hebei (HB, 6.06 µg/(m•year)). Distinct O trends between Beijing and other cities in BTH could not be attributed to the significant decrease in PM (from -5.08 to -6.32 µg/(m•year)) and CO (from -0.053 to -0.090 mg/(m•year)) because their decreasing rates were approximately the same in all the cities. The relatively stable O concentrations during the investigating period in BJ may be attributed to a faster decreasing rate of NO (BJ: -2.55 µg/(m•year); TJ: -1.16 µg/(m•year); HB: -1.34 µg/(m•year)), indicating that the continued reduction of NO will be an effective mitigation strategy for reducing regional O pollution. Significant positive correlations were found between daily maximum 8 hr average (MDA8) O concentrations and vehicle population and highway freight transportation in HB. Therefore, we speculate that the increase in rural NO emissions due to the increase in vehicle emissions in the vast rural areas around HB greatly accelerates regional O formation, accounting for the significant increasing trends of O in HB.
尽管近年来京津冀地区大气细颗粒物（PM）显著下降，但对流层臭氧（O₃）污染仍在增加。然而，该地区臭氧升高的内在原因仍不清楚。在本研究中，我们基于中国生态环境部2014 - 2019年期间的监测数据，分析了京津冀地区对流层臭氧及相关污染物（PM、NO和CO）的时空变化。结果表明，夏季北京（BJ，0.06 μg/(m³•年)）的臭氧浓度保持稳定，但天津（TJ，9.09 μg/(m³•年)）和河北（HB，6.06 μg/(m³•年)）的臭氧浓度显著增加。京津冀地区北京与其他城市之间明显的臭氧变化趋势不能归因于PM（从 -5.08降至 -6.32 μg/(m³•年)）和CO（从 -0.053降至 -0.090 mg/(m³•年)）的显著下降，因为它们在所有城市的下降速率大致相同。在研究期间北京臭氧浓度相对稳定可能归因于NO下降速率更快（BJ：-2.55 μg/(m³•年)；TJ：-1.16 μg/(m³•年)；HB：-1.34 μg/(m³•年)），这表明持续降低NO将是减少区域臭氧污染的有效缓解策略。在河北，日最大8小时平均（MDA8）臭氧浓度与车辆保有量和公路货运量之间存在显著正相关。因此，我们推测，河北周边广大农村地区车辆排放增加导致农村NO排放增加，极大地加速了区域臭氧形成，这是河北臭氧显著增加趋势的原因。
