2015—2021年京津冀地区空气污染物的时空变化特征

Spatiotemporal Variations of Air Pollutants in the Beijing-Tianjin-Hebei Region from 2015 to 2021

自改革开放以来,中国经济持续快速发展,与此同时环境也面临着挑战。在过去一段时间,全国城市普遍受到空气污染的严重影响,尤其是颗粒物(particulate matter,PM)污染和近期的臭氧(O_(3))污染。京津冀地区作为中国发展的关键板块,其环境问题更是引起了广泛的关注。在本文中,我们系统地研究了京津冀地区六种空气污染物(CO、NO_(2)、O_(3)、PM_(10)、PM_(2.5)和SO_(2))的时空变化特征。在2015—2021年,京津冀地区的CO、PM_(10)、PM_(2.5)和SO_(2)年浓度整体呈下降趋势,平均浓度分别降低0.11 mg/m^(3)、7.7 mg/m^(3)、5.4 mg/m^(3)和4.2 mg/m^(3),而NO_(2)和O_(3)-8h年平均浓度呈现先增后减的趋势。其中京津冀中南部地区SO_(2)、CO和NO_(2)的浓度较高,而京津冀北部地区的CO、NO_(2)和PM浓度较低;然而O_(3)受到空间变化的影响较小。在3月,京津冀地区几乎所有城市的PM_(10)呈上升趋势,特别是靠近内蒙古的张家口市。这可能是受到来自中国西北地区沙尘的影响。O_(3)的季节特征显示,O_(3)浓度在夏季到达高峰;其昼夜变化特征表明,O_(3)浓度在下午到达高峰。虽然京津冀地区的PM污染得到了有效改善,但污染物浓度仍高于中国环境空气质量(China national ambient air quality,CNAAQ)标准,并且该地区的O_(3)污染正不断恶化,未来需协同控制PM和O_(3)污染,以改善该地区的环境空气质量。

During a past time period,China has been widely affected by severe air pollution,particularly particulate matter(PM)and recent ozone pollution.As a key sector of China’s development,the Beijing-Tianjin-Hebei(BTH)region’s environmental problems are worthy attention.In this study,we systematically studied the spatiotemporal variations of six air pollutants(CO,NO_(2),ozone,PM_(10),PM_(2.5) and SO_(2))in the BTH region.From 2015 to 2021,the annual average concentrations of CO,PM_(10),PM_(2.5) and SO_(2) in the BTH region decreased at a rate of 0.11 mg/m^(3),7.7 mg/m^(3),5.4 mg/m^(3) and 4.2mg/m^(3) respectively,while the average concentrations of NO_(2) and O_(3)-8h showed a trend of initially increasing and later decreasing.The concentration of SO_(2),CO and NO_(2) was higher in the central and southern BTH region,while CO,NO_(2) and PM levels in the northern BTH region were lower.It was worthy noting that ozone was less affected by spatial changes.For almost all cities in the BTH region,monthly changes in PM_(10) showed an upward trend in March,especially in Zhangjiakou,near Inner Mongolia Autonomous Region,which may be caused by wind-blowing dust from northwest China.The concentration peaks of ozone’s seasonal and diurnal patterns appeared in summer and afternoon,which was in contrast with other pollutants.Although the PM pollution in the BTH region decreased,the overall concentration was still above guideline.In contrast,ozone pollution in the BTH region is deteriorating,and it is necessary to jointly control PM and ozone pollution to improve the ambient air quality in the future.