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Your holiday candles that smell of pomegranate, peppermint and pine may spark joy in your home, but they can also fuel your risk of heart disease and certain cancers, a new study finds.
“Our research shows that some home fragrance products may be detrimental to indoor air quality,” Asit Kumar Mishra and Marie Coggins, researchers from Ireland, wrote last week in the Conversation.
Here’s a look at the toxic gases and the irritating particulate matter released into the air when scented candles are burned — and how they can harm your health.
Volatile organic compounds
Firing up a candle can generate volatile organic compounds (VOCs), carbon-based substances that easily enter the air we breathe.
Not all VOCs are considered dangerous — but some can irritate the eyes, nose and throat and cause dizziness, drowsiness, nausea and loss of coordination.
Prolonged exposure to VOCs — which are also found in paint, varnish and cleaning supplies — can lead to constant headaches, liver and kidney damage, an increased risk of lung cancer and worse asthma symptoms.
CNN reports that paraffin wax, a cheap derivative of petroleum and the most popular candle fuel, is often the culprit for candle-related VOCs.
One particularly carcinogenic VOC is benzene, which has been linked to leukemia development with long-term, significant exposure. Formaldehyde, another VOC, has been deemed “carcinogenic to humans” because it’s been shown to cause nasopharyngeal cancer and leukemia in high amounts.
“In poorly ventilated rooms, we have observed that concentration of pollutants like formaldehyde reach levels that can cause upper airway irritation,” Mishra and Coggins wrote.
Many artificial fragrances used in candles also contain phthalates, which are semi-volatile organic compounds that don’t easily evaporate.
“The main concern is some scented candles contain synthetic fragrance and dye, which can potentially release harmful chemicals when burned,” Dr. Kunal Sood, a pain management specialist in Maryland, recently told Parade. “An example is phthalates, which are endocrine disruptors and have been linked to ADHD, asthma and even breast cancer.”
Toxic gases
VOCs are not the only potentially harmful gases associated with candles. Small amounts of carbon monoxide, sulfur dioxide and nitrous oxide can be emitted when candles are burned — and they can become particularly problematic in poorly ventilated spaces.
Carbon monoxide impairs oxygen delivery to tissues. Carbon monoxide poisoning can manifest as headaches, dizziness, nausea, fatigue and confusion. High exposure to the colorless, odorless gas can severely damage the heart and brain, potentially even leading to death.
For their part, sulfur dioxide and nitrous oxide can irritate the nose and throat, triggering coughing and breathing difficulties and aggravating asthma and heart disease.
Particulate matter pollution
Ignited candles also release particulate matter into the air, mostly in the form of soot that can irritate the lungs. Exposure to fine particulate matter pollution has been shown to increase the risk of heart disease and stroke.
Scented candles tend to produce more fine particulate matter than unscented candles, Mishra and Coggins noted.
“While using scented candles, for example, peak fine particle concentrations could increase to 15 times the limits prescribed by the World Health Organization,” they wrote. “These levels took a while to return to normal levels in underventilated rooms.”
How to safely burn candles
Mishra and Coggins have identified three major ways to reduce exposure to potentially harmful chemicals in scented candles.
- Use these products in large spaces, such as the living room.
- Make sure to open windows and check that interior vents aren’t blocked.
- Extinguish candles outside because most of the smoke is emitted when the candle is blown out.
