Do kitchen exhaust fans really work?

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Estoy de Acuerdo / I agree

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Many of us never think to turn on our kitchen exhaust fans until something starts
smelling too strongly or burning. However, the exhaust fan is one of our most useful tools for improving indoor air quality and can have a larger impact on your health than you may think.

I’m sure most of us heard of the controversy surrounding gas stoves recently. If you have a good kitchen exhaust system, then using it will certainly help reduce indoor air pollution associated with gas stoves. But even if you don’t own a gas stove, just the act of cooking produces many unwanted air pollutants that can be quite dangerous to your health over time. Fine particulate matter and gasses like nitrogen dioxide and formaldehyde can contaminate your air as a result of cooking. That is why restaurants are required to purchase large and expensive exhaust systems meant to protect their employees from cooking related air pollutants (and accidental cooking fires). For better or worse, there is no such requirement in the building codes of private homes. That means some of us may not even have a kitchen exhaust system. If you don’t have an exhaust system, opening doors and windows during cooking can help. And if you are lucky enough to have a good exhaust system, here are some tips for how to use it.

1) Exhaust fans connected to a duct which leads to the exterior of your building are the best option for keeping your indoor air clean. However, many apartments and other small buildings simply rely on a fan (often in the microwave or oven hood) which lightly filters and then recirculates the air without pumping it outside. These fans are better than nothing, so long as you remember to clean the filter frequently and consider opening a door or window to add in some extra ventilation.

2) Turn on the exhaust fan every time you cook, and use its highest setting. The noise of the fan can be annoying, but it is better than inhaling dangerous gasses and particles.

3) Cook on the back burners to increase the distance between you and any air pollutants coming off of your cooking, and to increase the chances that they get pulled into the exhaust fan.

4) Keep your exhaust vent on for about 15 minutes after you are done cooking. This helps to ensure that any remaining cooking related pollutants have a chance to be pulled out of your indoor air.

At the end of the day, air pollutants from cooking and gas stovetops are certainly not the most pressing threat to our health. However, if you can reduce them with a simple flick of a switch then why not?

"" This elegant kitchen has a nicely designed hood for filtering heat, smoke, grease and moisture.

Quick Image/Construction Photography/Avalon/Getty Images

Kitchen exhaust fans aren't just for when you accidentally burn the liver and onions. They're vital tools for improving indoor air quality, and by extension, protecting human health. But to see the benefits of these fans, you must actually use them, and regularly, even if your local building codes, like most, don't require them.

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Yes, exhaust fans help remove moisture, odors and oils that originate with cooking. But they do far more than that.

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You've undoubtedly seen ominous smog that hangs over heavily polluted metropolitan areas. Now, imagine that your kitchen stovetop might create more pollution than some places that have famously filthy air – for example, in one study more than half of California homes featuring gas stoves had pollutant levels exceeding limits for outdoor pollution. That's because cooking over high heat produces carbon monoxide, nitrogen dioxide, formaldehyde, fine particulate matter and other potentially dangerous byproducts. (Electric stoves don’t produce carbon monoxide and only small amounts of nitrogen dioxide, though they do produce fine particulate matter.)

Ducted hoods are the best solution to this problem, as they suck in contaminated air and then vent it to the building's exterior. For people with health issues or allergies, ducted versions by far the best option.

But in many millions of homes (like crowded apartment buildings), kitchen ductwork is structurally difficult or impossible. So instead, these spaces rely on simple fans, which capture grease and some particulates in a filter but otherwise do very little to remove pollutants. In fact, they simply recirculate the air in the room.

So, what are the best ways to combat kitchen smog?

• Be sure the hood is installed between 24 and 30 inches (61 and 76 centimeters) from the stovetop. If you're tall, you may have to make it higher to avoid head-bumping, but don't go above 36 inches (91 centimeters). Many hoods are simply installed too high and this drastically reduces their effectiveness.

• Turn on your exhaust fan every time you cook. If you use a recirculating fan, replace or clean the filter regularly. And realize that although these filters are good for capturing grease, they really aren't accomplishing much in terms of air pollution. In those situations, opening a kitchen window is your best bet.

• Cook on the back burners , which gives your hood and fans a better chance at grabbing and eliminating contaminants.

• Use the high-speed fan settings to maximize air flow. The downside of high fan speeds is, of course, that they tend to drown out conversation, but realize that the health benefits are worth the hiccups in chitchat.

Now That's Interesting

Wondering why that exhaust fan is so noisy? "The process of moving air makes noise," said Jennifer Gilmer of Jennifer Gilmer Kitchen and Bath in Chevy Chase, Maryland in the Chicago Tribune in 2010.

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