Winter brings shorter days and colder temperatures, and as a result, we spend a lot more time inside. To make our homes warm and cozy, we might crank up the heat, light a fire or burn candles, but doing so can negatively affect the air quality in the home.
While we tend to hear more about the risks of outdoor air pollution, indoor air quality can also be detrimental to our health. In fact, concentrations of indoor pollutants can be two to five times higher than outdoor concentrations. For some, this poor air quality causes headaches, fatigue, asthma attacks and more.
“People spend more than 90 percent of their day indoors in the United States, and that’s even higher in the winter,” says UNC Health pediatric allergist and immunologist David Peden, MD.
We talked to Dr. Peden about winter-specific air quality hazards and the steps to take to keep indoor air as clean as possible.
Indoor Air Quality Hazards During the Winter
“Winter is associated with an increased use of fuel,” Dr. Peden says. “Any fuel source will produce pollutants known as particulate matter, which are associated with many health problems.”
Particulate matter is a mixture of very small particles of ash, dust, pollen and chemicals. These particles linger in the air for long periods, particularly in winter when windows stay closed and they have nowhere to go.
Wood-burning stoves and fireplaces can produce significant amounts of particulate matter, but switching to a gas fireplace doesn’t eliminate the risk. Any gas appliance also requires fuel, so gas fireplaces and cooking ranges produce particulate matter as well as pollutants such as carbon dioxide, methane and nitrogen oxide. As you’re home more in the winter, you’ll increase use of many appliances, from stoves to heating units, all resulting in more pollutants in the air.
If you love to light a candle on a cold night, Dr. Peden says the occasional candle is fine. “Just remember that whenever you’re burning anything, there will be a byproduct,” he says. “A candle causes indoor smoke, same as a wood fire.”
Space heaters pose another risk.
“Every year, we see tragic headlines because people rely on heaters that are not designed to be used indoors,” Dr. Peden says. “Carbon monoxide is deadly, so extreme caution needs to be used with kerosene or gas-based heaters. Electric heaters are safer but still need to be used carefully.”
Mold can also be an issue during the winter months.
“Basement areas are particularly a problem,” Dr. Peden says. If you use a humidifier, clean its water tank regularly; dirty humidifiers can grow mold and bacteria.
Winter Indoor Air Quality and the Effect on Health
Particulate matter is linked with many health concerns, including heart disease, stroke, asthma, lung cancer and premature birth.
“Particulate matter is associated with an increased risk of heart attack,” Dr. Peden says. “It also causes vascular disease, so any organ served by those blood vessels will be affected.”
The particles can irritate the eyes, nose and throat, and they are problematic for people with existing lung issues, such as asthma or chronic obstructive pulmonary disease. While particulate matter aggravates everyone in different degrees, any irritation in the lungs can make cold and flu season more difficult.
“Particulate matter and air pollution can affect the way you respond to viral infections,” Dr. Peden says. “Winter is a robust time for viral infections that affect the lungs, and the severity of these infections can be compounded by airborne pollution.”
What You Can Do About Winter Indoor Air Quality
It’s not realistic to stop using appliances or never turn on the heat, but Dr. Peden says that careful and mindful use of fuel-burning units can help.
The first step is regular maintenance.
“Make sure chimneys, central heating units and other devices are being regularly serviced or cleaned,” Dr. Peden says. “We tend not to think about these things when it’s not cold, and then when it’s cold again, we start using them without checking the condition.”
Next, exercise caution about when you light a fire; some nights, an extra blanket or sweater can be just as cozy.
“If you’re going to burn a fire, wait until it’s especially cold outside,” Dr. Peden says. “The heat differential makes it more likely that the smoke will go out the chimney. Always make sure that a fireplace is well-attended. If a fire is still smoldering when you go to bed, you may not be aware of smoke causing indoor air issues.”
Anything that produces smoke or gases, from candles to a gas stove, should be monitored while in use. If possible, crack a window and use ventilation for stoves.
Dr. Peden says that HEPA filters can provide some help in cleaning indoor air, but they’re not a cure-all. More important, he says, is being mindful about when to use a fireplace or stove.
“Don’t be cold or uncomfortable, but just know that if you can smell smoke, you’re smelling particulate matter,” Dr. Peden says. “Be prudent and use common sense, and never use heating devices outside of their instructions of use.”
If you’re concerned that indoor air quality is affecting your health, talk to your doctor. Need a doctor? Find one near you.