How to keep the air in your home cleaner this winter, and why it's so important

We'll all be spending a lot more time at home this winter, and if making your environment ideal is a priority, don't overlook your home's air quality while thinking about other improvements.

After all, air-quality issues can impact our everyday well-being, and short- and long-term health. "Air pollutants are known to cause adverse health effects," said Parisa Ariya, an atmospheric chemistry professor at McGill University. According to HealthLink BC, we spend up to 90 per cent of our time indoors, and poor air quality "may cause headaches, tiredness, coughing, sneezing, sinus congestion, shortness of breath, dizziness and nausea," as well as cause irritation and exacerbate asthma and allergy symptoms.

According to Health Canada, the major sources of pollutants in your home include activities that involve burning, such as smoking, cooking, and heating a building; the use of household items from cleaners to candles, personal care products, building and hobby materials; dampness and water leaks; and poor ventilation. Plus, during the colder months in Canada, atmospheric changes that can trap pollutants, coupled with our use of heating sources, can mean more particles in the air both outdoors and indoors, explained Ariya.

While you can't control or eliminate all of these factors, here are three things you can do to keep the air in your home as fresh as possible this winter.

Reduce or eliminate common indoor air contaminants

"The first thing you should always try for any indoor air-quality problem is getting rid of the source," said Jeffrey Siegel, a professor at the University of Toronto's department of civil & mineral engineering. He noted dealing with the source is preferred to trying to purify polluted air.

The list of common indoor air contaminants is long and includes pets, smoking, dust, certain cleaning products and even gas stoves if you don't have a proper exhaust fan or range hood. Reducing the use and prevalence of these culprits can make a huge difference. 

Some of the worst offenders may surprise you. "Scented candles are horrible for indoor air quality," said Siegel. "Soy and beeswax are better than paraffin; paraffin is much better than any scented candles; [and] unleaded wicks are much better than wicks with lead in them. But any candle is a surprisingly large particle source." 

Misting humidifiers and essential-oil diffusers are two other common particle-generators in homes. "Essential-oil diffusers [can] generate just so many really hazardous particles," said Siegel. With an ultrasonic or misting humidifier, he recommends the use of distilled water to avoid having the minerals in tap water disperse into the air. 

Improve air circulation and ventilation 

One of the most simple yet very effective ways to enjoy fresher air indoors is to improve air circulation. "When you want to clear your home, leave the door and windows open to get the exchange of air and a dilution effect," said Ariya. 

You can also run your bathroom and kitchen fans (and portable fans, when it's not too cold) to encourage ventilation and reduce odours and pollutants.  

HVAC filters can also help with air quality. Of course, furnaces and HVAC systems don't run 24/7, and their filters only work when they do. Over a year, the central air system in the typical Canadian house is only running about 18 per cent of the time, noted Siegel.

Invest in a portable air cleaner 

A portable air cleaner or purifier is another reliable way to improve the air quality in your home. There are four main types, said Siegel, although some may have overlapping features: ones that use a fan and filter, ionization, photocatalytic oxidation or ultraviolet light. He recommends the classic fan-and-filter option, which represents the bulk of the models on the market. 

"[Ionization units] cannot actually clean that much air" said Siegel, adding "some of them produce ozone as a by-product of their operation. Ozone is a respiratory hazard." And he said devices that use photocatalytic oxidation are not as effective as fan-and-filter and can create by-products too. As for UV-light air cleaning machines? "To my knowledge, none have been demonstrated to be useful in indoor environments," he said. 

To find the right air cleaner for you, Siegel suggests researching the top-rated air cleaners on independent product-review sites such as Consumer Reports and Wirecutter. Ideally, it should be effective and not produce any ozone. "Those are the two big red flags," he said. Then, think about what you're trying to address in your home. Is it respiratory issues or allergy season stuffiness or cannabis smells from a neighbour, for example? 

"It's important to have a really good sense of what you're trying to do with the air cleaner," Siegel said. "There's no one magic air cleaner that does everything." For dealing with pet odours, as an example, he recommends looking for a purifier with an activated-carbon filter layer. And you may want to try out air cleaners in person to hear how noisy they are, if possible, or at least research online reviews that address noise. "Good air cleaners are noisy, and that's because moving air is noisy," he said.

Don't worry about the efficiency percentage rates advertised by many air cleaners, said Siegel, because that number doesn't necessarily indicate how much air they can move and treat. "All you should care about is the mathematical product of the flow rate and the efficiency, which in the portable air-cleaner world, we call the clean-air delivery rate, or CADR," he said. "That's the sole thing I tell people to buy air cleaners on." A machine's CADR will also tell you what size room it's appropriate for treating too. 

Whichever air purifier you go for, be sure to follow the manufacturer's instructions and recommended maintenance schedule. "This is very important," said Ariya. "People buy these instruments, and they never change the filter, or they never wash it." And be sure to pick one that is powerful enough for the space you'll be using it in. "[Don't use an] air cleaner that is undersized for the space that you're trying to clean; that won't [make] very much difference," said Siegel.

Truc Nguyen is a Toronto-based writer, editor and stylist. Follow her at @trucnguyen.