A soak in a steamy tub, surrounded by candles sure seems like a great way to unwind. But new research suggests that burning certain kinds of candles may generate indoor air pollutants.
Researchers at South Carolina State University studied petroleum-based and vegetable-source candles to determine their emissions. They let candles from different manufacturers burn for up to six hours in a small box (8 inches x 8 inches x 26 inches), and then collected and analyzed substances released into the air.
They found that paraffin-based candles -- the most popular kind -- emitted toxic chemicals like toluene and benzene. Soybean candles did not, according to the study, which was presented this week at the American Chemical Society meeting in Washington, D.C. Candles made of beeswax or soybean tend to make mention of that ingredient on their label; paraffin candles may not.
The researchers say that lighting a paraffin candle once in a while is unlikely to pose a health threat. However, frequently lighting many candles in an unventilated space could lead to problems, and may aggravate asthma, cause allergy-like symptoms, or irritate the respiratory tract. Health.com: 10 ways to fight indoor mold
However, whether some candles are safer than others is still debatable, according to one expert. "I think there's some controversy out there as to which candles are better than others," says George Thurston, Ph.D., an associate professor of environmental medicine at the New York University School of Medicine.
Thurston urges people to be prudent about lighting any kind of candle -- whether it's paraffin, beeswax, or soybean -- in an enclosed space. "Just lighting a match to start a candle creates sulfur pollution in the air," he adds. "It's one of the big sources of sulfur in the indoor environment, so using a lighter would probably be cleaner." Health.com: Why belly fat is bad for your lungs
While you aren't putting your life on the line by lighting a candle, he says you should exercise at least some caution. "You ought to try to minimize your exposure to paraffin wax candles," says Thurston. "And when you light any kind of candle, you might turn on the exhaust fan; even if it ruins the mood, it vents out the fumes. People just need to use common sense."
Candles are only one potential source of indoor air pollution.