Scented candles create indoor pollution ‘worse than diesel engines’, research shows

Be selective about where you burn your favourite candle

You may want to rethink rushing out to buy your favourite candle. Researchers believe making your home smell like cinnamon could potentially increase your risk of heart disease.

While a jasmine or vanilla-scented candle or wax melt may make your house feel more relaxing, there’s a chance they could potentially come with health consequences.

Many air pollutants can increase our risk of heart disease and lung cancer, and some scented products may actually make the air quality in our homes worse.

Researchers from the University of Galway and University College Cork published a report on the home fragrance products that may be "detrimental to indoor air quality”.

So which parts of scented products are to blame?

Volatile organic compounds

While not all volatile organic compounds are dangerous, some can ‘ irritate the eyes, nose and throat and cause dizziness, drowsiness, nausea and loss of coordination’, per the New York Post.

These carbon-based substances are often found in paint, varnish and cleaning products, and can be generated and inhaled when candles are burned. Prolonged exposure can cause headaches, damage to the liver and kidneys, worsened asthma symptoms and increase the risk of lung cancer.

The researchers in Ireland were particularly concerned about the inhalation of formaldehyde – a volatile organic compound that has been linked to nasopharyngeal cancer and leukaemia. “In poorly ventilated rooms, we have observed that concentration of pollutants like formaldehyde reach levels that can cause upper airway irritation."

A new study from Purdue University has also flagged terpenes as a concern when burning wax melts. 

Published in Environmental Science & Technology Letters, the researchers discovered that the chemical compounds found in scented wax can cause "significant" indoor air pollution".

The team said the rate of pollution is “comparable to those emitted by combustion-based scented candles, gas stoves, diesel engines, and natural gas engines”.

Published in Environmental Science & Technology Letters, the researchers found that the chemical compounds found in scented wax can cause "significant" indoor air pollution". Image: Pexels

American pain management specialist Dr Kunal Sood also highlighted that many artificial fragrances used in candles contain semi-volatile organic compounds that don’t easily evaporate.

Speaking to Parade, he said “The main concern is some scented candles contain synthetic fragrance and dye, which can potentially release harmful chemicals when burned. An example is phthalates, which are endocrine disruptors and have been linked to ADHD, asthma and even breast cancer.”

Toxic gases

You’ve probably heard of the dangers of carbon monoxide poisoning from running cars in garages. 

However according to the researchers, “Burning candles or incense sticks produces a complex mix of chemicals and particulate matter, including toxic gases like carbon monoxide, sulphur dioxide and oxides of nitrogen.”

Symptoms of carbon monoxide poisoning include headaches, dizziness, nausea, fatigue and confusion, but exposure to high levels of the gas can damage your brain and heart. 

Meanwhile, sulphur dioxide and nitrous oxide ‘can irritate the nose and throat, triggering coughing and breathing difficulties and aggravating asthma and heart disease’, as per the New York Post.

Light candles in larger spaces like living rooms, and open windows. Image: iStock

Particulate matter pollution

Lit candles can release particle matter, like soot, into the air. Exposure to fine particle matter pollution could irritate our lungs and increase the risk of heart disease and stroke.

Coggins and Mishra noted that scented candles can give off more fine particle matter than unscented ones. They said, “while using scented candles, for example, peak fine particle concentrations could increase to 15 times the limits prescribed by the World Health Organization.”

“These levels took a while to return to normal levels in underventilated rooms.”

The safest ways to burn scented candles

The researchers from Ireland suggested changing the way we burn our candles to limit our exposure to chemicals that could be harmful.

Their top tips include:

• Light candles in larger spaces like living rooms, and open windows
• Make sure your home’s vents aren’t blocked
• Try to blow out your candles outdoors, as the majority of the smoke is emitted when they’re extinguished.

Originally published as Scented candles create indoor pollution ‘worse than diesel engines’, research shows