@Article{Liu2022,
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 SO2 and NOx mixing ratios from 2004 to 2016 at a background  site in the North China Plain",
journal="Atmos. Chem. Phys.",
year="2022",
month="Jun",
day="01",
publisher="Copernicus Publications",
volume="22",
number="10",
pages="7071--7085",
issn="1680-7324",
doi="10.5194/acp-22-7071-2022",
url="https://acp.copernicus.org/articles/22/7071/2022/",
url="https://acp.copernicus.org/articles/22/7071/2022/acp-22-7071-2022.pdf",
url="https://doi.org/10.5194/acp-22-7071-2022"
}