Scented candles can make your room feel pleasant and relaxing but they can also be bad for indoor air quality. Studies have found mass produced scented candles contain chemicals that are harmful. The problem ingredients are found in the wax, wick and fragrance when the candle is burned and even when they are not lit.
The paraffin wax is a by product of petroleum and when burned it released bad chemicals called VOCs or volatile organic compounds like the ones found in diesel fuel smoke. The chemical names are benzene, toluene, acetone and soot. These candles can be like a small diesel engine producing dangerous chemicals into your home and can cause respiratory problems, allergies, skin problems and even cancer. The chemicals used in the fragrance and color dye can release VOCs like limonene, formaldehyde, petroleum distillates and esters even when they are not lit. These chemicals are known to cause headaches, allergies, respiratory issues and cancer.
The “cored wick” used in many candles have a metallic core wrapped in cotton to keep the wick from falling over. The tin and zinc metals used in the core can release trace amounts of lead particles. Imported candles could possibly have lead core wicks which has been banned from US manufactures.
So that attractive, festive and relaxing candle flickering on the counter is really just a diesel engine spewing toxic smoke into your home for you and your family to breath. I would suggest making some potpourri, or some wassail of simmer spices, or some essential oil in a diffuser.