Just a few weekends ago, we drove home early from Tahoe because the smoke from wildfires was so bad. The morning we left, the Air Quality Index was 398.

Because we had family with us, we took two cars instead of one: a Ford Excursion and a 2011 BMW X5.

The kids love to ride in the Ford because it has an entertainment system, so they can watch movies on the way home. But it’s not equipped with a cabin filter. When we were about to leave, there was literally smoke inside the car. Luckily, we had the BMW, which is equipped with a two-part cabin filter system. One set of the cabin filters cleans the air coming directly into the car and the other set cleans the air recirculating in the vehicle.

Because I love to test things, I sat in the BMW while it was idling for about five minutes. While sitting in the BMW, I could not even smell smoke. In the Ford, I had to wear an N95 and put a cloth mask over it. Without the masks, it was unbearable.

I have always touted how well cabin filters work, but I had no idea they could work this well. The wildfire smoke was a perfect example. This also got me thinking about how this would affect the engine’s air filter. Interestingly enough, I had replaced the Ford’s air filter approximately 4,000 miles ago. I usually replace that air filter between 15,000 and 20,000 miles, depending on how I use the car.

The primary purpose of the engine’s air filter is to stop bugs, dirt, sand and anything else floating around in the air from getting into the engine’s intake. Internal combustion engines are actually big air pumps. Yes, gasoline is the catalyst that makes the engine operate, but air flow is what gives the engine power – hence, the use of turbochargers and superchargers. The more air one can put through the engine, the more power the engine will create.

The less air flowing into the intake has the opposite effect. Dirty and damaged air filters can cause numerous problems with an engine. Obviously, the dirtier the air filter, the less air flow and less power.

Modern computer control cars need the air to flow correctly into the intake. If the air flow is incorrect, it can cause the engine to idle erratically and cut out on harder accelerations. This also causes the engine to be less fuel efficient. If the air filter is damaged and debris gets into the motor, it will scar and damage the cylinder walls. In extreme cases, it will cause the engine to lock up and fail.

Once I got back to the shop, I checked the Ford’s air filter and found that it was excessively dirty for a filter with only 4,000 miles on it. This proved to me how well the air filter was working. It also showed me the importance of using high-quality/factory air filters.

One should always take into account what environment you are driving in. If you have been driving in or around smoky areas, dirt roads or the beach, please check your air filters more often.

Matt Pataky owns Sunnyvale Foreign Car Service, 15 Pioneer Way, Mountain View. For more information, call 960-6988, email sfcsmv@gmail.com or visit sunnyvaleforeigncar.com.