> Is there anything good samaritan citizens can do locally (on a standard residential lot) to improve the particulate pollution levels outdoors around their house? (and possibly their neighbors' too?).

I would say electrifying your home would be a good first step. For example, we could replace following at home starting with:

Gas Furnace & AC -- Heat pump

Gas cooktop -- Electric cooktop

Gas Blowers, Mowers -- Electric versions of same