However, depending on the type, they may not prevent engine gases such as carbon monoxide and nitrogen oxides from being emitted. Improper use and maintenance can lead to engine problems. Vehicles not equipped with the devices would still be a potential engine exhaust source. Re-circulating overhead air filtration units can save on heating costs. Properly positioned, they can do an effective job of removing airborne particulate.
Special filters can remove some air borne combustion gases.
Knowing when filters are no longer effective, and properly replacing them can be a problem. Ensure that the annual Right to Know training required in Massachusetts includes the potential hazards of engine exhaust fumes within fire stations and other enclosed spaces.