A Breath of Fresh AirAir Quality

Canadians spend about 90 percent of their time inside and, despite rising pollution, air quality is often worse indoors than out. Although air purifiers don't affect pollutants trapped in furniture and carpets, they can improve air quality in your home by reducing and removing airborne pollutants, such as dust and dust-mite feces, mould spores, pet dander and pollen. These contaminants can trigger allergies, lung infections and other respiratory illnesses.

Several types of stand-alone room air purifiers are available, from mechanical filters and ultraviolet light to ionic generators and hybrid units that combine more than one system.

Problem: pollen and other allergens

Solution: A simple and inexpensive solution to capturing indoor allergens is using a high-efficiency filter in your furnace and changing it every 90 days. Choose one with electrostatically charged fibres, which are more efficient than fibreglass ones. There are endless options from Filtrete's Micro Allergen to Elite Allergen furnace filters, which capture more than 90 percent of large air pollutants while still providing proper air flow. Filtrete's Smog Reduction filters also reduce smoke, mould and ground-level ozone.

The Asthma Society of Canada recommends HEPA-filtered air purifiers to capture pollen. HEPA, which stands for High Efficiency Particulate Arrestor, is a mechanical purifier with a mat-like filter that traps pollutants. It removes about 99.9 percent of particles as small as 0.3 microns in the room, but doesn't eliminate chemical fumes, cigarette smoke or odours. HEPAs trap allergens efficiently and don't create harmful by-products such as ozone.

Portable, stand-alone ionic generators are quiet and effective in eliminating pollen and other fine particles but don't eliminate odours or kill germs. They use static charges to trap particles on a collector plate. They're also controversial as some emit ozone as a by-product, which can negatively affect people with asthma and allergies. Consumer Reports Magazine has given some ionic systems low clean-air delivery ratings.

And take note: Health Canada has warned against using ozone purifiers. Ozone is a key component of smog. Exposure to higher levels of ozone poses possible health issues and it's believed ozone purifiers do little to remove indoor air pollution.

Problem: gases, chemicals and VOCs

Solution: carbon air purifiers are useful for trapping odours and absorbing chemicals and gases, such as volatile organic compounds (VOCs) found in paints and furniture, which can pass through other particle filters, but they don't remove larger particles. As carbon filters fill with dirt, they need to be replaced in order to work effectively.

Problem: air-borne viruses, bacteria, and mould

Solution: Along with trapping dust mites, pollen and chemical gases, Ultraviolet light systems use electromagnetic radiation or UV light to sterilize viruses, bacteria and mould spores that enter the purifier. In order to be effective, the lamp must be kept clean as dust and other film that might coat the light bulb can lower UV output.

When looking for a unit, make sure it has the seal of approval from The Association of Home Appliance Manufacturers (AHAM). It gives each product a clean air delivery rate (CADR), which denotes the volume of filtered air output when the device is working at its highest speed. Higher CADR numbers equal more powerful units.