Air Purification near you

Each technology targets something different, and none does everything. Portable units simply plug in; the in-duct options are installed by an HVAC technician as part of the forced-air system.

A portable HEPA unit concentrates its cleaning on one room, which makes it the go-to for bedrooms, home offices and smoke events. An in-duct upgrade reaches every room the ductwork serves, but only while the blower runs and only as far as the system's airflow allows. Homes heated by baseboards, radiators or ductless heat pumps have no central ducts to filter, so portable units are the practical choice there.

Furnace filters are rated on efficiency scales, the most common being MERV (minimum efficiency reporting value): the higher the rating, the finer the particles a filter catches, but a denser filter can also choke airflow. Health Canada advises using the highest quality filter your ventilation system can handle, based on the manufacturer's recommendations, so ask your HVAC technician what your blower and ducts will tolerate before upgrading. Many homes combine the two: a better furnace filter plus a portable unit in the room where people sleep.

Some devices sold as air cleaners work by producing ozone on purpose. Health Canada advises against using ozone generators in homes: the level of ozone they produce may harm your health, and they also create other dangerous chemicals. It lists coughing, irritation of the eyes, nose and throat, chest discomfort, shortness of breath and decreased lung function among the effects of ozone.

Other electronic cleaners can release ozone as a side effect. Health Canada's advice for any air cleaner is to avoid devices that produce ozone, and it points to the list kept by California's air regulator of air cleaners that have passed testing for ozone emissions.

Germ-killing claims bring rules of their own. Health Canada says certain UV radiation-emitting and ozone-generating devices must be registered by its Pest Management Regulatory Agency before they can be sold or used in Canada, and registered devices appear in its Pesticide Product Information Database. It also warns that exposure to UV light from these devices may cause serious injuries, including severe burns to the skin and eyes, one more reason an in-duct lamp is installed by a technician and switched off before anyone opens the panel.

Wildfire smoke contains fine particles (PM2.5), the kind portable air cleaners are designed to filter. Health Canada's advice during smoke events is to keep windows and doors closed as much as possible, use the highest quality filter your ventilation system can handle, run a certified portable air cleaner that can filter fine particles, and limit exhaust fans such as bathroom fans. It adds that filters should be changed regularly during smoke events, since clogged filters aren't effective at removing smoke, and that keeping cool comes first when extreme heat and poor air quality arrive together.

A practical way to put that advice to work is to choose one room, often a bedroom, where the household can spend the smokiest hours: close its window, run a portable air cleaner sized for it and keep the door shut. If you can't keep the air clean indoors, Health Canada suggests seeking out local cleaner air spaces.

Health Canada suggests choosing by the clean air delivery rate (CADR), which describes how well a unit reduces tobacco smoke, dust and pollen, and picking the highest tobacco smoke CADR that fits your budget for the size of the room. Packaging usually lists the CADR and the room size the unit suits. A small unit in a large, open living area will barely make a dent.

A filter only works until it's loaded. Health Canada advises cleaning or replacing an air cleaner's filter as the manufacturer recommends, and more often during smoke events.

Health Canada says the best ways to improve indoor air are to remove the source of contaminants and to ventilate with clean outdoor air. Before buying equipment, look at what is putting pollutants into the air, and whether the house brings in enough fresh air to dilute them.