Luo Hongyan, Tang Xiao, Wu Huangjian, Kong Lei, Wu Qian, Cao Kai, Song Yating, Luo Xuechun, Wang Yao, Zhu Jiang, Wang Zifa
LAPC & ICCES, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029 China.
University of Chinese Academy of Sciences, Beijing, 100049 China.
Adv Atmos Sci. 2022;39(10):1709-1720. doi: 10.1007/s00376-022-1346-5. Epub 2022 May 29.
China national air quality monitoring network has become the core data source for air quality assessment and management in China. However, during network construction, the significant change in numbers of monitoring sites with time is easily ignored, which brings uncertainty to air quality assessments. This study aims to analyze the impact of change in numbers of stations on national and regional air quality assessments in China during 2013-18. The results indicate that the change in numbers of stations has different impacts on fine particulate matter (PM) and ozone concentration assessments. The increasing number of sites makes the estimated national and regional PM concentration slightly lower by 0.6-2.2 µg m and 1.4-6.0 µg m respectively from 2013 to 2018. The main reason is that over time, the monitoring network expands from the urban centers to the suburban areas with low population densities and pollutant emissions. For ozone, the increasing number of stations affects the long-term trends of the estimated concentration, especially the national trends, which changed from a slight upward trend to a downward trend in 2014-15. Besides, the impact of the increasing number of sites on ozone assessment exhibits a seasonal difference at the 0.05 significance level in that the added sites make the estimated concentration higher in winter and lower in summer. These results suggest that the change in numbers of monitoring sites is an important uncertainty factor in national and regional air quality assessments, that needs to be considered in long-term concentration assessment, trend analysis, and trend driving force analysis.
中国国家空气质量监测网络已成为中国空气质量评估和管理的核心数据来源。然而，在网络建设过程中，监测站点数量随时间的显著变化很容易被忽视，这给空气质量评估带来了不确定性。本研究旨在分析2013 - 2018年期间站点数量变化对中国全国及区域空气质量评估的影响。结果表明，站点数量变化对细颗粒物（PM）和臭氧浓度评估有不同影响。2013年至2018年，站点数量增加使全国和区域PM浓度估计值分别略有降低，降幅为0.6 - 2.2微克/立方米和1.4 - 6.0微克/立方米。主要原因是随着时间推移，监测网络从城市中心扩展到人口密度和污染物排放较低的郊区。对于臭氧，站点数量增加影响了估计浓度的长期趋势，特别是全国趋势，该趋势在2014 - 2015年从略有上升变为下降。此外，站点数量增加对臭氧评估的影响在0.05显著性水平上呈现出季节差异，即新增站点使冬季估计浓度升高，夏季降低。这些结果表明，监测站点数量变化是全国和区域空气质量评估中的一个重要不确定性因素，在长期浓度评估、趋势分析和趋势驱动力分析中需要加以考虑。
