Try these tips to enjoy candles without polluting your indoor air:
• Support your local beekeeper. Paraffin candles release chemicals because of improper combustion: The flame doesn't get hot enough to burn the oil completely, and chemicals are released as a result, Massoudi writes in his study. Beeswax candles burn at lower temperatures and don't have that problem. They also smell sweet without any added chemical fragrances, and some people believe that the negative ions in the wax actually improve your indoor air quality as the candles burn.
• Don't burn GMOs or rain forests. Massoudi compared the paraffin wax candles in his study to soybean wax candles, which didn't emit any of the pollutants that the petroleum-based paraffin did. However, many soy candles are made from genetically modified (GMO) soybeans, which decrease biodiversity and can contaminate organic soybean crops. Palm oil, another vegetable wax used in candles, comes from palm tree plantations, for which rain forests were burned or clear-cut.
• Buy the right kind of oils. In this case, essential oils. Even beeswax and plant wax candles can be scented with synthetic fragrances, which can contain phthalates that can interfere with your hormone system. Phthalates can also build up in household dust and linger for long periods. So if you're going for scented candles, look for ones that are scented with essential oils rather than chemical fragrances.
• Trim the wicks, and use your common sense. Keeping wicks trimmed to about ¼" will cut down on any soot that may come from candles, soy wax, beeswax or otherwise. Also, keep candles out of drafty windows where drapes may come in contact with the flame, and don't leave them unattended.
• Use outdoor air to improve indoor air. If you're burning candles to improve the smell of your home, you're going about it the wrong way. "Some people just don't open the door and get fresh air in their homes," says Massoudi. That's a lot more effective at freshening up a space than polluting candles can be.