@Article{acp-24-9515-2024,
AUTHOR = {Rowell, A. and Brean, J. and Beddows, D. C. S. and Pet\"aj\"a, T. and V\"or\"osmarty, M. and Salma, I. and Niemi, J. V. and Manninen, H. E. and van Pinxteren, D. and Tuch, T. and Weinhold, K. and Shi, Z. and Harrison, R. M.},
TITLE = {Insights into the sources of ultrafine particle numbers at six European
urban sites obtained by investigating COVID-19 lockdowns},
JOURNAL = {Atmospheric Chemistry and Physics},
VOLUME = {24},
YEAR = {2024},
NUMBER = {16},
PAGES = {9515--9531},
URL = {https://acp.copernicus.org/articles/24/9515/2024/},
DOI = {10.5194/acp-24-9515-2024}
}