Are your scented candles killing you?

The allure of scented candles has taken the globe by storm. Once confined to religious ceremonies or emergency lighting, these fragrant flames have evolved into the must-have decorative and "self-care" items, particularly in the aftermath of the pandemic.

A 2018 French study, which replicated realistic use, found that the most concerning substances released by scented candles include formaldehyde, acrolein, and particulate matter. As a result, the scientists suggest that people should not overuse scented candles, avoid direct inhalation of smoke and ventilate the room after use for safety.

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A common indoor air pollutant, formaldehyde can irritate your eyes, nose, throat, or lungs and trigger asthma attacks even at low concentrations. Prolonged exposure can cause cancer, according to the California Air Resources Board. It's also released by carpets, furniture, building materials, body and hair washes, and nail polish.

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The wellness trend, the COVID-19 pandemic, and even the war in Ukraine are fueling a boom in candles, particularly the scented variety. According to market analysis, people spent $12.88 billion on candles in 2022 and the market is expected to grow 5.7% per year until 2030.

According to a 2015 study published in the Journal of Hazardous Materials, scented candles are potent sources of volatile organic compound (VOC) emissions. This includes when they are burning and when they are unlit.

For some, their candle passion knows no bounds – or budgets. There are those who, with money to spare, don't blink an eye before shelling out as much as $2,500 for a single luminary, like the Lalique Épines Platinum Edition Scented Candle. And it's not just a solitary brand; several command prices ranging from hundreds to thousands of dollars.

For just $75, you could also buy the infamous Gwenyth Paltrow Goop label scented candle called "THIS SMELLS LIKE MY V A G I N A." While it did sell out fast, it's back in stock.

A 2021 study in 'Environment International' found that scented candles released more VOCs like benzaldehyde and limonene than unscented candles Mostly, the pollution didn't break air safety guidelines, but for benzo[a]pyrene and acrolein, long-term concentrations were exceeded with some candles.

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Burn scented candles in a small room, no matter how much they cost, and you will likely notice soot build up on the walls over time. That's because burning candles releases particulate matter, including soot, into the air, and these fine particles can penetrate the lungs and have serious health effects depending on the exposure. One 2016 study found scented candles emit more soot than unscented candles.

A U.S. mom discovered her baby's nose was full of soot after she had left two scented candles burning for around six hours the night before. This is what she said his nostrils looked like even after cleaning them out.

Image: CBS New York, 'The Dangers of Scented Candles' / YouTube

She later checked the candles, and they advised users not to burn them for more than three hours at a time. A New York doctor said that "patients come in all the time" with similar problems.

Image: CBS New York, 'The Dangers of Scented Candles' / YouTube

Like limiting burn times, the National Candle Association gives other little-known facts about how to reduce soot. They include "trimming the wick to a quarter inch before every use to promote proper flame height and keeping the candle away from drafty areas to avoid flame flickering."

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There has been a lot of debate about the type of wax burned, but a limited number of scientific studies. One from 2002 found that paraffin candles produced more soot, and little to none was observed from soy wax candles. However, another study found the three waxes to be similar. Paraffin wax is made from petroleum byproducts, so it's considered less environmentally sustainable.

What's really in many scented candles and other household products can be a mystery, and its ingredients are often just listed as generic terms like "fragrance" or "essential oils" even though they can be mixtures of several hundreds of chemicals. According to a 2017 study in 'Building in Environment,' no country legally requires full fragrance disclosure.

A 2019 paper in 'Cancer Prevention Research' suggests that scented candles emit hazardous chemicals that could be risk factors for bladder cancer. The researchers say the link hasn't been proven, but more studies are needed and consumers should be warned about risks, the chemical composition of candles, and how to use them properly.

A 2023 study in Saudi Arabia found that scented candles were commonly used among university students, particularly women. However, those who were exposed to burning candles for more than one hour showed higher occurrences of headache, sneezing, and wheezing.

Perhaps the most dangerous type of scented candles is those with lead wicks, as they can emit relatively large amounts of lead into the air when burned, which is especially dangerous for children. In the U.S., lead wicks were banned in 2003, so check local regulations and chuck old candles just in case.

U.S. Firefighters respond to an average of 7,400 home structure fires each year that were started by candles. On average, they cause 90 deaths, 670 injuries, and $291 million in property damage per year, according to the National Fire Protection Association.

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Overall, experts say burning scented candles in large rooms that are properly ventilated (i.e. not bathrooms) for a limited amount of time with properly trimmed wicks is generally safe. However, when it comes to air quality, no candle will be better than a regular candle, and evidence suggests regular candles are generally better than scented ones. But there are other considerations when it comes to making the decision like mood and a relaxing fragrance.

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According to Swiss technology company IQAIR, truly clean air smells like nothing at all. But if you are comforted by fragrance, fragrant flowers, the use of essential oils in a diffuser, simmering spices on the stove, or creating potpourri are safer alternatives than scented candles.

Flameless candles are another great alternative to capture the warm ambiance of a candle flame without harming the air you breathe at home. But nothing is perfect, and one 2013 study found that 8% of batteries ingested by children came from flameless candles.