Indoor Air Pollution and Your Health Free Information from EHSO

Candles and Indoor Air Quality

Candles add to the warmth & atmosphere of a home, but some candles can contribute to an indoor air pollution problem by emitting particulate matter (candle soot) into the air. Candle pollution not only discolors the walls, ceilings and contents of a home it can also contaminate the ventilation system's ductwork. This is especially true of ducts constructed from fiberglass "duct-board". It appears that petroleum-based (paraffin) candles and scented and/or aromatic candles are the worst offenders. Most candles on the market today are made from paraffin wax or a blend of paraffin and other waxes. Paraffin is a derivative of petroleum. When burned they release carcinogenic toxins such as benzene, toluene, formaldehyde, acetaldehyde, acrolein and soot into the air. The emissions from paraffin candles contain many of the same toxins produced by burning diesel fuel. It is like starting up a diesel engine inside you home!

Scented candles may trigger allergic reactions. The symptoms include itchy and watery eyes, sore throat, blocked nasal passages, headaches, hives, skin irritations and asthma-like conditions. People with asthma and respiratory allergies may experience more severe reactions.

If the light colored fabrics in your home begin to look rather dingy or gray, if plastic items in the house begin to accumulate a dark film, if your electronic equipment has discolorations especially around vents (ie. computers, disc drives, etc...), if the television or computer monitor screen is covered with a thin dark residue that wipes off with a clean cloth (this film will appear darker than regular household dust on a clean cloth) you could have an IAQ (Indoor Air Quality) problem resulting from candle soot.

Gel candles are also petroleum-based. Although there are urban myths circulating on the internet that claim they explode; that is not really a problem. The glass container can shatter from excessive heat (but not explode) and they can emit the same toxins as paraffin candles.

Safer, natural alternatives to paraffin based candles

Soy candles generally last 30% longer than petroleum-based candles. Soy candles burn slower and cooler, are non-toxic, less likely to trigger allergies, clean up with soap and water, and produce very little soot. This tends to make them more animal and child-friendly than traditional candles. Soy candles are labeled explicitly, so if it does not say Soy on the label, it isn't. Soy candles have a more opaque appearance and usually have with a whitish film.

Beeswax is returning to popularity. Beeswax is less likely to trigger allergies. It generally does not produce toxins or soot when burned. It tends to be more expensive than paraffin candles but also burns longer. Do read the labels, as some manufacturers may have added paraffin.


In addition to airborne pollution, candles present a substantial fire safety issue. See this page from the National Fire Protection Association for facts and figures about candle-caused fires and safety tips. The NFPA also has an executive summary of the research into home candle fires. Their magazine (free) also has an article about candle safety, too.

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  • Switch to Beeswax or Soy candles.
    bulletWatch out for shiny metal wire inside the wicks of candles. Those made outside of the United States often contain zinc, or worse, lead. Look for those made in the U.S. or for pure paper or cotton instead.
    bulletKeep wicks trimmed to one-quarter inch for more complete combustion
    bulletKeep candles out of drafts. Wind causes incomplete burning, burns the candle faster and puts more pollution into the air.
    bulletBeware of candles advertised as slow-burning. Some (not all) may have additives that are more dangerous. The candles can often be recognized by the greasy feel to the touch. Stick to all natural or manufacturers that use safe natural additives.
    bulletIf you want a scent or aromatherapy, put a few drops of scented oil in a defuser, which is a tray made to fit on a light bulb, or simply put the drops into some boiling water. these avoids burning the oil.
  • Candles in jars deprive the wick of oxygen and produce more soot. Don't use candles in jars when the wick is below the level of the top of the jar or when the candle leaves a soot ring on the jar's lip. The soot may also be an indication of lead dust from a metal wick.
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If you suspect a problem:

1) Stop burning candles immediately!

2) Check and/or change the filter in your heating/cooling system, save the filter if it is more

3) Continue to change the filter more frequently than usual, you should observe a

4) Depending on the extent of property damage you may want to contact your

5) You may also want to seek the advice of an Indoor Air Quality or Building

6) If evidence is compelling towards candles causing the problems, you may want to stop using them or switch to safer alternatives

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For other sources of information about candle pollution and safety, see

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