Except for the fact that the Bay Area has some of the worst air pollution in the country [1], and air pollution exposure is positively associated with loss of white matter [2].

So I would say maybe it's a wash?

1 - https://www.lung.org/our-initiatives/healthy-air/sota/city-r...

2 - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132565/