I use this [0] GVR mask when working around concrete dust, and I've found it to be very comfortable and effective. That doesn't directly answer your question a

I use this [0] GVR mask when working around concrete dust, and I've found it to be very comfortable and effective. That doesn't directly answer your question about urban particulates and PM 2.5, but if you read its specs and it sounds appropriate, I can recommend the product. [0] https://www.amazon.com/Respirator-replaceable-reusable-filters-included/dp/B0FD8XCBHN https://www.amazon.com/Respirator-replaceable-reusable-filte...