How scented Christmas candles can increase the risk of heart disease, lung cancer

Your pomegranate, peppermint, and pine-scented holiday candles may spark cheer in your home, but they may also raise your risk of heart disease and certain cancers, a new study finds.

“Our research shows that some household fragrance products can be harmful 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 irritating particles released into the air when scented candles are burned—and how they can harm your health.

Volatile organic compounds

Burning 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 persistent headaches, liver and kidney damage, an increased risk of lung cancer and worse asthma symptoms.

CNN reports that paraffin wax, a cheap petroleum derivative and the most popular candle fuel, is often the culprit for VOCs associated with candles.

A particularly carcinogenic VOC is benzene, which has been linked to the development of leukemia with long-term and significant exposure. Formaldehyde, another VOC, is considered a “human carcinogen” because it has been shown to cause nasopharyngeal cancer and leukemia in high amounts.

“In poorly ventilated rooms, we have observed that the concentration of pollutants such as formaldehyde reaches levels that can cause irritation of the upper respiratory tract,” Mishra and Coggins write.

Many artificial fragrances used in candles also contain phthalates, which are semi-volatile organic compounds that do not evaporate easily.

“The main concern is that 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 for Parade. “One example is phthalates, which are endocrine disruptors and have been linked to ADHD, asthma and even breast cancer.”

Toxic gases

VOCs aren’t the only potentially harmful gases associated with candles. Small amounts of carbon monoxide, sulfur dioxide and nitrogen oxide can be emitted when candles burn – and they can become particularly problematic in poorly ventilated spaces.

Carbon monoxide impairs the delivery of oxygen to tissues. Carbon monoxide poisoning can manifest as headaches, dizziness, nausea, fatigue and confusion. High exposure to the colorless and odorless gas can severely damage the heart and brain, potentially leading to death.

In turn, sulfur dioxide and nitrous oxide can irritate the nose and throat, causing coughing and difficulty breathing and worsening asthma and heart disease.

Particulate pollution

Burning candles also release particles into the air, mainly in the form of soot that can irritate the lungs. Exposure to fine particle pollution has been shown to increase the risk of heart disease and stroke.

Scented candles tend to produce more fine particles than unscented candles, Mishra and Coggins noted.

“For example, when using scented candles, peak concentrations of fine particles can increase up to 15 times the limits prescribed by the World Health Organization,” they wrote. “These levels took some time to return to normal levels in unventilated rooms.”

How to burn candles safely

Mishra and Coggins have identified three main ways to reduce exposure to potentially harmful chemicals in scented candles.

• Use these products in large spaces, such as the living room.
• Be sure to open the windows and check that the interior vents are not blocked.
• Blow out the candles outside because most of the smoke is released when the candle is blown out.