In the summer of 2023, an eerie and lingering haze blanked skies all across the East Coast following a record wildfire season in Quebec. New York City’s Air Quality Index reached a hazardous level of 465 as the smoke eventually drifted into cities like Boston, Washington, D.C., and Philadelphia. More than 350 million people were exposed to record levels of unhealthy air before it finally cleared.

Canada is fighting hundreds of wildfires again this year. Shifting winds are steering wildfire smoke across the U.S. once more, triggering alerts in cities outside the regions typically associated with wildfire risk. Minneapolis, Chicago, and Detroit (where I live) each rank among the most impacted cities right now.

If you’re like me and you deal with sinus pressure and allergies, you can feel the effects of these air quality alerts, even indoors. When you have to be out and about during an alert, here are three tricks I use to minimize the impact of poor air quality in my vehicle.

Check the Air Quality Index

Try to get everything done in one trip if possible

The EPA’s AirNow tool pulls readings from official monitoring stations across the country and turns them into a simple, color-coded score for your zip code. It functions as a website at airnow.gov and as a free app for iPhone and Android.

In the case of the screenshot above, I know that in Detroit right now, where I live, it is exceptionally bad. If where you live has a similar alert and you are able, try running your errands at another time. In the interest of better fuel economy, I combine my errands and grocery shopping in one trip, but I find that strategy also helps when air quality alerts are in the forecast.

Several states also have their own air quality trackers, often with monitoring specific to a given location and even at the neighborhood level. For example, the Texas Commission on Environmental Quality publishes a daily outlook for metro areas across the Lone Star state, as does the New York Department of Environmental Conservation.

You can also search for “[your state] air quality,” which should turn up a more local option if one exists.

Check your cabin air filter

Look for a “MERV-13 equivalent” rating

Nearly every vehicle sold in the last two decades has a cabin air filter, tucked behind the glove box or under the hood, that traps dust, pollen, and other particles before they reach the vents. Lingering wildfire smoke, in addition to a normal day of dust and pollen, can shorten the usable life of your cabin air filter.

In the dash camera footage above, you can see me driving around the Detroit metro, including merging onto I-696. The sky is hazy and gray, and you can feel it in your lungs the moment you step outside, even if it’s only a short walk to your car.

If your cabin air filter hasn’t been replaced in a year or more, or you cannot remember when you last changed it, now is a good time. You can DIY it at home, or have your mechanic replace it the next time you are in for an oil change.

Your home wages the same battle against wildfire smoke as your car does, though it uses a filter rating system different from that of automobiles. MERV, or Minimum Efficiency Reporting Value, measures how well a home HVAC filter captures particles by size, with a range of 1 to 16 (the higher the number, the smaller the particles it filters out). The EPA recommends a rating of 13 or higher for filtering wildfire smoke indoors.

Some aftermarket automotive brands advertise higher-end cabin filters as “MERV-13 equivalent” for comparison, using electrostatic, multi-layer designs to trap fine particulates.

Switch to recirculate mode

Vary the cycle on longer trips

Credit: Carl Anthony | How-To Geek

Here in Detroit, I like to cruise main roads like Telegraph and Woodward with my windows down and my sunroof open, but when there are air quality alerts in the forecast, I just crank the AC.

The HVAC system in your car draws air from two sources, either outside the vehicle or from inside the cabin. In most cars, the recirculate button is indicated by a small curved arrow or loop with the silhouette of a vehicle. Pressing it stops the system from drawing in outside air and instead recycles what is already inside.

Recirculate mode does not heat or cool the air on its own; it only changes where that air comes from. Paired with the air conditioning, though, I find it often cools the interior just as fast as pulling in outside air, even on a hot day.

Some newer vehicles are equipped with air quality sensors that detect pollution and switch to recirculate mode on their own.

One final tip while driving

Air quality alerts usually ease once a weather system moves through and clears away the smoke, though the timeline varies from one event to the next. Until then, the tips above can help keep the air inside your car a little cleaner and fresher than the air outside.

As a final tip, be mindful that recirculate mode traps your exhaled carbon dioxide inside the cabin. On longer drives, that could leave you feeling drowsy. If you have a long road trip on your schedule, try to alternate between regular mode and recirculation periodically.