We don’t always think of the quality of the air as part of a climate control system, but one of the most important improvements in the internal atmosphere of vehicles in recent years comes from the dust filters that clean the air passed through the heating,

air-conditioning and ventilation system. The most obvious benefits are a reduction in road dust in the passenger compartment, making life more comfortable for almost everyone, but particularly for those who have allergies or who drive in very dusty places.

The filters do more than that, however. You’ve probably tried to clean air conditioner evaporators and heater cores by spraying various chemicals through the ductwork. If there is much growth of mold at all, it’s a pretty thankless task, unlikely to work for long. With a dust filter, however, it is possible to prevent that problem from arising at all. If the mold spores stop on the accordion-fold paper, you can remove them with the old insert.

Besides what the cabin filter does for the driver and passengers in terms of the comfort level from a cleaner air to breathe, it also has a safety function. Most people are relatively careful about keeping the outside of the windshield clean, so they can see what is coming down the road. It’s much less common, however, for car owners to clean the inside of the windshield. Besides being less convenient to clean, the buildup of dust and grime is much more gradual, so there isn’t the kind of perception of the vision-obstructing layer there is from road spray or bugs.

The cabin filter can’t eliminate that problem, but it can reduce it substantially. The amount of dust and small particulates that used to collect on the inside of the windshield is much lower, so the need to clean the glass from the inside is proportionately reduced.