@Article{acp-22-7071-2022,
AUTHOR = {Liu, X. and Ran, L. and Lin, W. and Xu, X. and Ma, Z. and Dong, F. and He, D. and Zhou, L. and Shi, Q. and Wang, Y.},
TITLE = {Measurement report: Variations in surface SO$_2$ and NO$_x$ mixing ratios from 2004 to 2016 at a background site in the North China Plain},
JOURNAL = {Atmospheric Chemistry and Physics},
VOLUME = {22},
YEAR = {2022},
NUMBER = {10},
PAGES = {7071--7085},
URL = {https://acp.copernicus.org/articles/22/7071/2022/},
DOI = {10.5194/acp-22-7071-2022}
}