How to make your indoor air quality safe

Surprisingly, the air inside our homes may be more hazardous than the air outside. Here’s how to make sure your indoor space is healthy.

Natural gas–powered stoves are popular around the world, including in the European Union, where they’re used by almost one quarter of the population. But experts have recently raised concerns: Unlike electric and induction types, gas stoves give off nitrogen dioxide (NO2) when ignited—and often at levels that exceed the safety limit set by the World Health Organization.

When the stoves are in use, the NO2 can cause coughing and wheezing. People with asthma and chronic obstructive pulmonary disease may experience inflamed airways as well.

To protect your family, turn on the extractor fan every time you cook; they’re designed to remove smoke, grease and pollutants that are released during cooking. But less than 20 per cent of people use them consistently, says Brady Seals, a co-author of the study and a manager with the US-based environmental think tank RMI. “Use the back burners, as they’re closer to the exhaust intake, and open a window—even for just five minutes.”

VOCs, including benzene and formaldehyde, are sometimes found in household items like paint, carpeting and detergents. While most VOCs do not pose a significant health risk, a 2005 study published in the Journal of Occupational Health found prolonged, concentrated exposure in workplaces, such as industrial factories or nail salons, to be associated with cancer, liver damage and neurological problems.

To reduce your exposure, choose paint and furnishings that are certified as low or no VOC. When you’re using cleaning products, especially those with bleach, ventilation is key, says Trevor VandenBoer, an environmental chemistry researcher at York University in Toronto. “Use an exhaust fan, open a window and give the room time to air out—ideally an hour.”

Many VOCs stick to other particles, such as dust, skin flakes and lint, so VandenBoer recommends an activated carbon filter air purifier. Make sure it can capture particulates less than 2.5 microns in diameter (about one-30th the width of a human hair) because that size can be inhaled deep into your lungs. And vacuum often with a high-efficiency particulate air (HEPA) filter that traps small particles.

An invisible, odourless gas that comes from the breakdown of uranium in soil, radon leaches in from cracks and joints in the foundation (whether you have a basement or not) and can waft up several levels. Inhaling high levels of radon, especially over many years, can cause malignant cell growth in the lungs, making radon one of the leading causes of lung cancer worldwide.

Across Europe, standards vary for what are deemed safe levels of radon, but it’s a good idea to find out what level is safe in your area—and then check your home. Indeed, one of the 12 recommendations of the European Commission’s Code Against Cancer advises citizens to “Find out if you are exposed to radiation from naturally high radon levels in your home. Take action to reduce high radon levels.”

Experts say a radon test kit should be as essential as smoke and carbon monoxide detectors. Called a dosimeter, it must be placed in your home’s lowest occupied level for at least three months, since radon levels can vary. If your dosimeter indicates unsafe levels, a radon-mitigation expert can fix the problem by installing a ventilation pipe in your home’s foundation.

Common household moulds like aspergillus, penicillium and cladosporium are present in approximately 13 per cent of European homes. They’re mostly harmless, but when damp indoor conditions encourage growth, they can release dust-like spores. This can trigger eye, nose and throat irritation, sneezing, coughing and asthma attacks.

Patches of black or green specks can appear on walls or tiles, along with a musty odour. It can be cleaned with vinegar or dish detergent. For patches larger than a bath towel, call a mould-removal specialist. Mould hides in the walls, so it’s best to mitigate the growth.

As a habit, turn on an exhaust fan in the bathroom and run a dehumidifier to keep humidity levels below 50 per cent. Most have a hygrometer to measure humidity; home-humidity meters are also widely available.