How to test and improve the indoor air quality in your home

Types of indoor air pollutants

Dust mites and pet dander

Dust mites – and pet dander, if you own pets – are both notorious for worsening indoor air quality. Both can aggravate hay fever, eczema, and nasal inflammations. They can be found everywhere in your home, from the air to hard surfaces to soft furnishings, but are particularly embedded in soft furnishings like bedding and carpet.

Mould

Mould – a type of fungus that grows and spreads on damp, poorly ventilated areas – has airborne reproductive spores that can float around indoors. Mould spores can cause serious respiratory infections, worsen asthma, and irritate your eyes, nose and skin.

Read more on how to prevent mould in your home, and how to buy the best dehumidifier to help prevent mould.

Combustion particles (smoke, soot, ash, gas)

Combustion particles include smoke, ash and gases (e.g. carbon monoxide). These particles are so tiny that they are very easily breathed in. They can aggravate asthma, irritate your throat, nose and eyes, and contribute to lung cancer and chronic respiratory disease.

Combustion particles can be produced by gas cooking appliances (one reason why many Victorians are switching to induction cooktops), fireplaces, heaters that burn gas, coal, wood or kerosene, car exhaust from enclosed garages, and bushfires.

“A licensed gas plumber can check your gas appliances and piping for any leaks that may pose a risk to air quality as well as fire,” says Head of RACV Trades, Kieran Davies.

Volatile organic compounds (VOCs)

Volatile organic compounds (VOCs) are chemicals like formaldehyde that contain carbon and evaporate at room temperature. These chemicals can enter your airways, causing headaches and irritation to the throat, nose and eyes.

VOCs can be present in many household products: paint, varnish, adhesives, cleaning agents, scented products, synthetic fabrics, and more. Off-gassing – when VOCs evaporate into the surrounding air – mostly occurs when the products are new or freshly installed, or with higher temperatures.

Lead and asbestos

Older buildings may contain lead or asbestos, which are toxic products.

Lead is typically found in pre-1970s homes, in products such as paint, electric cabling, plastic pipes, and flashings. Stripping old paint in pre-1970s homes is one way you could come into contact with toxic lead.

Asbestos can be found in many pre-1990 homes, in products like vinyl flooring, cement sheets, pipe lagging, roofing sheets, and fire-resistant boards. While asbestos was once widely used for its strength and fire-resistance, its fibres can be released into the air, inhaled, and damage lung tissue. It has also been found to cause various cancers. Thankfully, asbestos has been completely banned in Australia since December 2003.

Mould can be very harmful to your health. Image: Getty

How to test your home’s indoor air quality

You can quickly check the indoor air quality in your home with an indoor air quality monitor. These are often built into air purifiers, which ‘read’ the surrounding air quality and display the results on their screens or related app.

Air quality monitors will often give PM2.5 readings. ‘PM’ stands for particulate matter and ‘2.5’ for particulates that are 2.5 micrometres or less in diameter. These are particulates that can easily be breathed in. The higher the PM2.5 reading, the worse your indoor air quality.

Regularly clean your home to keep it freer from pollutants. Image: Getty

Top tips to improve indoor air quality

Regularly clean your home

The simplest way to improve and maintain your indoor air quality is to regularly clean your home. Here are some cleaning tips to best improve your indoor air quality:

• Use microfibre cloths to dust surfaces. They are electrostatic: their fibres rub together to attract and catch the dust mites. Other cloths and dusters tend to stir the dust particles up into the air. Don’t forget spots like skirting boards and windowsills.

• Wash your towels and bedding at least once a week. These fabrics collect all types of allergens like dust mites, plus dead skin (which dust mites feed on) very quickly. Using a hot wash cycle is best, if possible. Pillows and cushions should also be regularly replaced.

• Invest in a high-quality vacuum cleaner. Look for the term ‘HEPA filter’ (high-efficiency particulate air filter) when purchasing. These vacuum cleaners can capture tiny particulates, removing them from the air.

• Maintain air conditioning filters. “Cleaning the filters of central or split system air conditioners can not only help remove dust from your home but also keep them working efficiently," Kieran says. “If your system is old, needs a service or is hard to access, a professional tradie can help.”

• Choose hard floors over carpets. Carpet traps dust and other pollutants within its fibres. People with allergies, crawling babies and young children playing on the floor are particularly affected by carpeted areas. If possible, replace carpets with smooth flooring, like polished wood, vinyl linoleum, or ceramic tiles. Remember to clear off any dust from the floors before mopping, which will otherwise spread the dust around. If you can’t replace your carpets, vacuum them regularly with a high-quality vacuum cleaner.

• Clean kitchen exhaust fans and range hoods regularly. Even if your kitchen vents to the outside, fat droplets and other pollutants can catch on the range hood and inside the vent. Clean the exhaust fans and rangehood as per the manufacturer’s instructions to prevent a build-up of bacteria. Similarly, you should regularly clean the filters in vacuums and extractor fans.

Make sure your heating and cooling system vents outdoors. Image: Getty

Ensure proper ventilation throughout your home

Adequate ventilation helps remove contaminated air from your property and introduces fresh air indoors. Air rooms whenever possible by opening doors and windows – just remember to close and lock them before you leave the house to help prevent burglary. 

The exception to this advice is during bushfires, nearby construction, or other events that could bring polluted air into your home. During these times, keep your doors and windows closed and use air filters and purifiers.

Vent air pollutants outside and reduce indoor humidity (which can cause mould) by regularly cleaning exhaust fans, rangehoods, flues and chimneys. Kitchens, bathrooms and laundries all require adequate ventilation. Keep in mind that extractor fans must be installed by a licensed electrician.

In addition, make sure your heating and cooking appliances are regularly serviced to ensure they don’t leak gases into your home.

Finally, keep doors connecting to garages tightly sealed and don’t keep vehicles running inside the garage.

Purchase an air purifier

Electronic air purifiers can effectively filter out air pollutants to improve your indoor air quality. They will either use a HEPA filter to collect and store pollutants from the air, or they will release negatively charged ions to make pollutants stick to surrounding surfaces for easy cleaning.

Smart air purifiers can even adjust their fan speeds according to the indoor air quality, so that they function more strongly in more polluted air.

Place the air purifier in your bedroom for best results, since you likely spend the most time in your house asleep in bed. If you’re housebound or work from home, placing the air purifier in your living room or office during the day is preferable.

Swap out the air filters every three to six months, or earlier if they become clogged. If your model has a washable pre-filter, dust it off and wash it regularly to keep your air filters cleaner for longer.

Install a carbon monoxide alarm

Carbon monoxide is an air pollutant that can be deadly if inhaled. It can be a by-product of home appliances like fireplaces, grills and stoves.

Since it can’t be seen, smelled or tasted, you may not be able to detect a carbon monoxide leak in your home. Having a professional install a carbon monoxide alarm on each level of your home can alert you and prevent carbon monoxide poisoning.

Make sure any indoor plants are not toxic to your pets. Image: Getty

Invest in indoor plants

Indoor plants can help to remove air pollutants, especially carbon dioxide. Here are the best indoor plants for air purification, including the snake plant, the spider plant and the rubber plant.

If you have pets, make sure that any plants you bring indoors are non-toxic. Read more on pet-friendly flowers and houseplants.

Minimise products with VOCs

Volatile organic compounds (VOCs) can be present in many construction, renovation and furnishing materials. VOCs are often detectable because they give off an odour – for example, fresh paint or carpet adhesive.

Read product labels for details on VOCs. You can also ask the company for the product’s material safety data sheet (MSDS). Products certified by Good Environmental Choice Australia, or rated E1 or E0 by European Emission Standards are generally good choices.

When painting or carpeting, keep rooms fully ventilated until their odours disappear.

You should also avoid fragranced cleaners, which most likely contain VOCs.

Use natural, non-fragranced products when cleaning to help avoid VOCs in your home. Image: Matt Harvey

Seek professional help when renovating

If you plan to renovate your home, it’s a good idea to seek professional help – particularly if your home was built pre-1990s. These homes may be at risk of exposing you to lead and/or asbestos if you start renovating.

Even if your home is new, contact a professional to remove any existing paint. Sanding down dried paint releases lots of fine particles into the air. Professional painters can capture the dust before it spreads throughout your home.