Are you a particularly not-so-DIY type? This video from the Family Handyman Youtube channel can walk you through the process for a basic window unit (though you can remove the filters on most units while they’re installed as well):

Cole Goldklang, founder of Breasy, which rents and and installs AC units in New York City, also suggested paying attention to a bit of routine AC maintenance many people ignore: Rinse your AC filter with water, and change it every four to six weeks. He said that every few years you should get a new filter from a hardware store or online.

Most window ACs primarily recirculate indoor air — but some units have fresh-air vents or outdoor air dampers. That’s usually a small lever on the side. You’ll want to check for it as the air quality index in the city remained “moderate” or “unhealthy for sensitive groups” Friday, and might get worse again .

First up, the EPA advises that you keep windows and doors closed — and says using the AC instead of bringing in fresh air is a generally good idea.

We’re barely out of a heatwave, and still blasting the AC. HVAC experts and government agencies suggest a few ways to keep the indoor air seeming more like…something you’d want to breathe.

The air has been hazy. The sun was hanging red in the sky. New Yorkers have been searching for respite from the Canadian wildfire smoke that’s been invading our lungs — but getting inside isn’t always enough.

Goldklang said if your AC is making weird noises, if it’s not cooling as well as it should or if your electricity bills seem unexpectedly high, it’s time to check the filters. Most AC systems have a light or other alert mechanism to remind you.

Don’t assume that just because an AC is aging, it’s no good, he said. But “you want to make sure that there are absolutely no gaps if you're looking to minimize any sort of risk of air coming into an apartment,” he said.

Goldklang noted windows ACs have “accordion arms,” those side panels used to fill the gaps between the unit and a window frame. He suggested buying foam and putting it on the indoor part of that space to insulate it better, and have less air coming from outside. The EPA also suggests being mindful of any gaps around your windows that could let outside air in.

That’s not a bad idea for keeping your utility bills under control, too. It’ll make your AC less noisy, less warm air will make its way inside during the summer, and less cold air can get inside if your AC is still in place during the winter.

What about central AC?

If you have central air conditioning, maintenance can be a little trickier. If you’re a renter, you have to hope (or insist) that the landlord has checked the air filters.

"You're kind of at your landlord's mercy in terms of them cleaning their systems," said Goldklang.

William Bahnfleth, professor and director of architectural engineering at Penn State University, was skeptical many New York City central air conditioning systems were ready for the wildfire smoke.

"On short notice and the way this kind of emergency has popped up, I would doubt that most systems are prepared to deal with it," he said.

Anything special to know about portable ACs?

The EPA says if you have a portable air conditioner with a single hose vented out of a window, you should use it as little as is practical, because it may draw more smoke inside.

If your portable AC has two hoses, you want to make sure the seal to the window is as tight as possible.

What won’t the AC do?

Goldklang and Bahnfleth both said you shouldn’t rely on an air conditioner to clean the air once it’s inside — that’s the job of an air purifier or other air cleaner.

“[The AC] may keep your apartment or your room cool, but it's not the device that you want to use to try to ensure that you've got good air quality,” he said.

Bahnfleth said that he arrived Thursday vacation in Minnesota for a — where the Air Quality Index was over 400. That places the air quality in the worst possible range, “hazardous” — far worse than New York City has experienced this week, and more like what we saw when the skies turned orange in 2023.

The EPA has a guide to picking out an effective air cleaner system here.

It says any portable air cleaner should be placed where people spend the most time, and run on the highest fan speed.

And if you don’t have any kind of air cleaner, you can DIY one with a few filters, a fan and some crafting spirit.

How else can I protect my home (or myself)?

Don’t make things worse. The EPA points out you’re not doing yourself any favors smoking or vaping indoors when you’re trying to keep the air clean.

Using gas, propane or wood-burning stoves and furnaces won’t help either. Neither will spraying aerosol products, frying foods or burning candles.

And if you don’t love housework, this is a great excuse to avoid vacuuming (unless you’ve got a HEPA filter).

Beyond that, consider taking a break from strenuous activity to avoid inhaling more smoke than strictly necessary.