Can Air Conditioning Make You Sick? Here's What Science Has to Say

Is your unseasonable summer cold the result of your decadent new air conditioner?

With their ability to recreate cold-weather conditions similar to the winter tundra, air conditioners can produce the same kind of climatic environment one normally experiences in the winter cold and flu season. Some draw a line between these chilly conditions and summertime sickness, reasoning the technology that keeps us from overheating may actually be subjecting us to more traditionally wintry illnesses. But how much truth is there to that claim?

As it turns out, the question is more complicated than it sounds. While anecdotal evidence may lead you to believe air-conditioning can make you sick, the science is clear: There is no reason to believe it's behind your midyear cold.

Common trends: The most common claims that air conditioners can cause a cold stem from some alarming trends associating their use with symptoms ranging from mucous membrane irritation to headaches and difficulty breathing. Studies have linked air conditioning use to increased sickness in office workers and more frequent visits to ear, nose and throat specialists. 

However, scientists haven't yet been able to nail down a specific cause of this correlation, partially because a variety of models make assessing the data more complicated. Things are further muddled by the wide range of people who use air conditioners and the fact that the minor symptoms reported could not explain incidents like hospital visits.

Figuring this out: According to WebMD, "The most common cold-causing viruses survive better when humidity is low — the colder months of the year. Cold weather also may make the inside lining of your nose drier and more vulnerable to viral infection."

While air conditioners cannot account for the lower humidity aspect of the cold-causing viruses, as the New York Times reports, air conditioners can dehydrate the mucous membranes of the nostrils, which could make the nose a more attractive environment for viral reproduction. So perhaps blasting your air conditioner can make your body somewhat more susceptible to infection.

While that explanation seems clean and simple, there may not be any real science to back it up. Common Cold Centre director Ron Eccles told Mic via email, "One could speculate that chilling and drying of the nose weakens defenses to infection, but there are no experimental studies on this published to my knowledge."

However, that's not to say air conditioners' effects on air can't play some role in exacerbating problems.

"I think it's fair to say that changes in air quality, and that can include particulate matter ... can cause people who who have lung problems to have flare-ups," American Lung Association senior medical advisor Dr. Al Rizzo told Mic, adding that poorly maintained units with dirty filters or pooling water could "promote aerosolized bacteria and mold and sometimes be detrimental."

In general, though, since indoor air pollution is surprisingly widespread in American homes, the American Lung Association actually recommends people with asthma use air conditioners to promote air circulation.

"If it's kept in working order and kept clean, it can be helpful," Rizzo concluded. "In general, patients with lung disease do better with temperature control that is colder rather than hotter."

So why the connection? While the science is more than out on the matter, it's possible some people may be incorrectly associating summer symptoms of allergies with the indoor temperature changes caused by air conditioning, which could explain some of the persistence of anecdotal reports of air conditioning-induced respiratory illness. And while poorly maintained units with dirty or grime could cause infection or illnesses, there's nothing inherently armful about the systems themselves.

Until scientists are able to pin down more evidence tying air conditioners to colds, your primary concern with rampant air conditioner use should be the environmental cost associated with making temperatures more pleasant for humans.