Many people are asking themselves this question in recent weeks. The quick answer is this: I’m not sure. I’m not a scientist of that sort, but chances are the air in your vehicle is being filtered. Starting around the early 2000 model-years, most vehicles were equipped with a cabin air filter, also referred to a pollen filter. These filters clean the outside air before it enters the inside of the car, and can also filter the air as it’s recirculated around the cabin, if that option is selected by the occupant. The filters come in several different price points, with quality being measured at filtration ability in parts-per-million (ppm). Some of highest quality filters use charcoal to help filter out particulates and pollens. The filters are changed at scheduled intervals when the vehicle is serviced during scheduled maintenance. The filter can be changed more often at a relative low cost. Many people aren’t aware that a filter can be plugged more than 20-25%, and still look completely clean. Particles measured in PPM are very small!
If the option is available to you, I recommend driving with the windows up, the air conditioning on, and the “recirc” setting selected. The recirc button may look like this:
How it works is like this: The blower fan for the heat and air conditioning can either pull air in from outside or inside the car. By selecting the recirc option, the car closes a flap inside the air flow ducting, forcing the blower to recirculate the air inside the cabin instead of drawing “fresh” air from outside. Coincidentally, the recirc option makes your AC work much better, as the system is now cooling air which has already been cooled, instead of continuously trying to cool much hotter air from outside. So, keep all the windows and flaps closed while we struggle through the season of smoke, and after it’s all done, call and schedule your vehicle for scheduled maintenance and/or engine and cabin air filter changes. Thanks to all the brave people fighting fires to keep us safe this fire season. Drive on!