A breath of fresh air, a cool breeze, the smells of pine, jasmine, roses, and wisteria… all excellent reasons to tear open the shutters and let a bit of the outside move through your home. Many of us instinctively appreciate the way things just feel better when there’s a cleansing draft moving through the house—especially in warmer weather—but thanks to the miracle of modern air conditioning and central heating, many of us find ourselves keeping the windows closed and letting the HVAC system regulate the temperature. But did you know that it’s actually good to open the windows once a day for more than just the sensations and smells of the great outdoors?

We hear about smog and pollution, smoke warnings, and lots of hemming and hawing about outdoor air quality. But did you know there’s such a thing as indoor air quality—known as IAQ in environmental studies circles? Not only is it a real thing, but the Environmental Protection Agency explains that poor air quality inside of your house or office is one of the top five environmental health concerns and can have health major impacts even years after exposure (yikes!). Many things play a role in the quality of your home’s IAQ, from tobacco smoke, mold, and pet dander to harsh chemical cleaning products and air fresheners, even household stoves, heaters, and fireplaces.

And what about those chilly winter months? We know you don’t want to lose that precious heat, but most home heating systems don’t bring any fresh air into the house and evidence that suggests that lack of proper ventilation and poor indoor air quality causes sensory irritation, invokes subtle effects on the central and peripheral nervous system, triggers respiratory disease, asthma, and/or allergies, and has other nasty effects.

Sobered by that knowledge, you might be inclined to never close the windows again, but a even little bit of fresh air does a world of good. How, then, to keep your IAQ A-OK? Prevailing wisdom is that at least 5 minutes—and ideally 15 to 20 minutes—a day of ventilation significantly improves indoor air quality. For a strong ventilation, open the front and back door, along with windows on the path in between, to get the baddies out. Opening the windows also lets the outdoor microbiome mingle with your indoor one, diversifying the good bacteria in your home to help strengthen your immune system, says Justin Sonnenburg, Ph.D., associate professor of microbiology and immunology at Stanford University.

You can also minimize exposure to many of these risk factors by cleaning the house regularly with safe, nontoxic cleaners like Aunt Fannie’s and avoiding harmful chemical household cleaners—especially for daily use—as well as investing in a HEPA air filter, vacuuming often with a HEPA filter-equipped vacuum, and even keeping a few air-cleaning plants around.

So go ahead, shout it from the windows, “I want healthy indoor air quality and I don’t care who knows it!” Actually, maybe don’t shout it, but do open those windows!

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