Health alert. A lot of oil change shops and vehicle owners do not know their vehicles have a Cabin Air Filter. Changing out the filter is very important. When driving your car a lot of harmful elements-mold spores, allergens, road dust , and so much more enters your automobile through the vent. When they enter your car, it becomes more concentrated than the outside air. That means, breathing all these harmful substances can endanger your health, as well as your passengers with asthma, allergies, or lung problems.