%0 Journal Article %T Measurement report: Variations in surface SO2 and NOx mixing ratios from 2004 to 2016 at a background site in the North China Plain %A Liu, X. %A Ran, L. %A Lin, W. %A Xu, X. %A Ma, Z. %A Dong, F. %A He, D. %A Zhou, L. %A Shi, Q. %A Wang, Y. %J Atmos. Chem. Phys. %D 2022 %8 June 01 %V 22 %N 10 %I Copernicus Publications %@ 1680-7324 %F Liu2022 %R 10.5194/acp-22-7071-2022 %U https://acp.copernicus.org/articles/22/7071/2022/ %U https://acp.copernicus.org/articles/22/7071/2022/acp-22-7071-2022.pdf %U https://doi.org/10.5194/acp-22-7071-2022 %P 7071-7085