In the summer, many of us can’t bear to live without it, but even so, cool air is a modern luxury that sometimes seems to freak people out. “We had forms of heating for a very long time before we ever had air conditioning,” says Dr. Stan Cox, senior scientist at The Land Institute in Salina, Kansas, and author of Losing Our Cool: Uncomfortable Truths About Our Air-Conditioned World. Cox points out that as recently as the 1960s, only 12 percent of Americans had some kind of AC in their homes. While heat was an absolute necessity for people to live in cold climates, Cox says, air conditioning is more of a newcomer on the climate-controlled front. And research suggests that a little freaking out is warranted. “If you have a badly maintained or badly designed AC system, whether it’s in your home or office or vehicle, it can become contaminated and potentially harmful,” says Dr. Mark Mendell, an epidemiologist with the California Department of Public Health. Mendell studied the health effects of air conditioning systems while with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory.

He says worsening asthma problems and allergies are two health issues that can stem from contaminated AC units. He also mentions an ominous-sounding phenomenon: sick building syndrome. “We started seeing it in the 70s and 80s,” Mendell says. “People in office buildings started saying the building was making them sick.” He says sick building syndrome was associated with a range of seemingly unrelated symptoms: nasal congestion, breathing problems, headaches, fatigue and irritated skin. His own research has linked AC systems in office buildings to many of those same symptoms. “The most likely explanation is that there may be some microorganisms growing in the system that may have some subtle effect on certain people,” Mendell says. “But it’s not clear how many people are sensitive to this or how big of a problem it is.” Unlike heating systems, the process of cooling hot air creates a lot of moisture and condensation, which must be channeled away, Mendell explains.

If your AC system does a bad job of this, whether due to poor maintenance, damage or shoddy design, it can become a breeding ground for bacteria and fungi. To protect yourself, he says, your best defense is a well-maintained and routinely serviced AC unit. hidden ac unit(HVAC repairmen, you owe this guy!)air conditioner window unit not cooling But Mendell is also quick to point out that AC has been firmly linked to many health benefits. are carrier central ac units good“Outdoor air pollution is common in urban environments, and especially in heavy traffic,” he says as just one example. “AC filters out the particles in outdoor pollutants.” Exposure to airborne pollution particles can raise your risk for hospital admissions and premature death due to cardiovascular issues, says Dr. Michelle Bell, a professor of environmental health at Yale University.

Bell’s research found the use of well-maintained AC use lowered a person’s risk for these health complications. “Use of central air conditioning causes less outdoor air pollution to penetrate indoors compared to open windows,” she says. Both Bell and Mendell also say that during intense heat waves, AC saves lives. If this seesawing between AC’s benefits and risks feels disorienting, you’re not alone. “Anyone who does research on these systems will admit there’s still a lot of things we don’t know,” Mendell says. What isn’t in doubt, though, is air conditioning’s very real and harmful impact on the planet. “The headline issue is its contribution to greenhouse warming,” says Cox, the Land Institute environmental researcher. Indoor heating has long been a bigger contributor than AC to the accumulation of harmful greenhouse gasses, Cox says. But the U.S. population’s southward shift has allowed AC to catch up—and maybe draw even. Despite his concern for the planet, Cox says that AC can be life saving and beneficial.

But he takes issue with what he calls our “lavish” use of any climate control conveniences. Setting our thermostats a bit higher in summer and a little lower in winter would benefit the environment without affecting anyone’s health, he says. In fact, a little thermal discomfort could be good for you. People tend to eat more and gain more weight when the temperature is perfectly cozy, Cox says. “When we’re a little cold or a little warm, our metabolism runs faster,” he says. Research backs him up: One recent study found exposure to cold temps—enough to make you shiver—may increase your body’s stores of healthy, energy-burning brown fat. Cox adds that your body can adapt to a range of temperatures. (This is why you break out the shorts and T-shirts on that first 65-degree spring day, but the same thermostat reading in autumn sends you hunting for jeans and sweaters.) So if you can cut out the heat or cold for a week or two, your body will often acclimate to temperatures you found unpleasant at first—and easing up a bit on the AC will make the planet thank you, too.

The weather in Northeast Ohio seems more an more unpredictable - at times even extreme - with each passing season. During the summer months, the need for central air conditioning has become almost mandatory in most areas. Despite the relief it brings on a hot day, there are some health considerations you should be aware of before keeping that air conditioning running 24/7, as you may be tempted to do. Besides the concerns of high utility bills that result from excessive use, you might ask yourself, "Does air conditioning overuse pose any health risks?" While overexposure to air conditioning itself is not linked to actual illness, constant exposure can contribute to indoor discomfort for various reasons. Here are some common health issues associated with the overuse of central air conditioning. Indoor Air Pollution -- Studies indicate that indoor air pollution can sometimes be far greater than outdoor air pollution. If your home's air is poorly circulated or contains allergens, you may start to suffer from nasal issues, itchy eyes, headaches, dizziness or difficulty breathing, according to the United States Consumer Product Safety Commission.

In extreme cases, asthma attacks and pneumonia may develop.  If the pollution within the home is allowed to persist for years, your symptoms may become severe or more serious conditions may develop. Dry Skin and Nasal Passages -- Long hours of being exposed to central air conditioning can dry out the skin. Keeping the skin adequately cared for with moisturizers can help reduce flaky, often itchy, skin. Since air conditioned air is usually lower in humidity, it contributes to indoor comfort in the summer, but will also lead to drier skin and air passages. Colds and Other Respiratory Illnesses -- Not only will your skin dry out from air conditioning overuse, but your mucus membranes will also dry out, which can leave you vulnerable to upper respiratory infections, fatigue and other illnesses, according to Global News. Having a humidifier professionally installed will help to balance the humidity in the home. Heat Intolerance -- Spending long hours in an air conditioned home may cause you to suffer heat intolerance when you go outside.

You may feel exhausted from exposure to the heat of the outdoors. Often, dizziness, headaches, difficulty breathing and even heat stroke may occur to a person who has spent long amounts of time in an air conditioned space. Worsened Allergies & Ear Irritations -- If you suffer from allergies during the summer months, running your air conditioning constantly can worsen your symptoms if your system has not been regularly maintained. In addition, if mold is circulating in the air, it can accumulate in the folds of a person's ears, causing them to dry out and possibly bleed. The constant noise generated by some less-efficient central air conditioning systems may also potentially contribute to hearing damage. What are the Common Causes? Dirty filters, uncleaned ductwork and vents and poor overall maintenance can cause your air conditioning system to release mold and other contaminants into the air you breathe. Safe Use of Your Air Conditioning System The causes of indoor air pollution and the other discomfort discussed here are typically a dirty system and dirty filters that are used without maintenance for a long period of time.