The American Lung Association recommends three steps to protect yourself indoors:
Use a heat recovery ventilator or an energy recovery ventilator to quietly provide the fresh filtered air you need while quietly removing stale polluted air.
Seal leaks in the building shell to block entry of unfiltered outdoor air during the heating and air conditioning seasons. NOTE: Sealing leaks also blocks entry of dust and insects.
Use space and water heating systems that cannot put combustion gasses into the building interior.