Yes, significantly, and almost entirely a result of individuals no longer using their cars.

Note these studies took place at various different times during the lockdown, and focus on different scopes of data:

https://pcc.uw.edu/blog/research/how-did-covid-19-affect-our...

https://www.nature.com/articles/s41558-020-0797-x

https://earth.stanford.edu/news/covid-lockdown-causes-record...