There are two effects here:
- Some pollutants increase simply because higher temperatures cause the reactions which form them to run faster
- Getting rid of combustion prevents the emission of pollutants which don't have a meaningful climate impact in addition to preventing the emission of CO2, which does. This is a co-benefit of electrification, and doing something like moving to e-fuels would mean seeing the same problems for human health.
I wish the article did a better job of explaining this, which is why I didn't post it when first published.