What impact did the COVID-19 lockdown in spring 2020 have on the exchange of ultrafine particles between the city and ground-level atmosphere? In a recent paper in the journal Science of the Total Environment, we have investigated this question and can show how strongly the turbulent flux of ultrafine particles was influenced by the decreases in traffic activity during the lockdown.
Straaten, A., Meier, F., Scherer, D. and Weber, S., 2022. Significant reduction of ultrafine particle emission fluxes to the urban atmosphere during the COVID-19 lockdown. Science of The Total Environment: 156516. https://www.sciencedirect.com/science/article/pii/S0048969722036130