Are Candles Bad for Indoor Air? Beeswax, Soy, and Paraffin Candles Compared

Are candles bad for indoor air, and are beeswax candles healthier? All burning candles release fine and ultrafine particles and some gases, and in Danish homes that burned candles they accounted for almost 60 percent of residents’ ultrafine particle exposure. Normal, occasional use is not considered a known health risk for most people, but frequent use in small, closed rooms adds to indoor pollution. Beeswax and soy candles may produce less soot than some paraffin candles, though research comparing them directly is limited.

Candles are a holiday tradition and a comfort ritual for many households, and natural beeswax candles are often marketed as a cleaner, healthier choice. At the same time, air quality researchers have shown that candles can be one of the largest sources of tiny airborne particles inside homes, especially in winter when windows stay closed. The real picture sits between “candles are toxic” and “natural candles are harmless.” This article explains what candles release, what studies of people exposed to candle smoke show, how wax types, wicks, and fragrance compare, and how to enjoy candles while keeping indoor air cleaner.

What Do Burning Candles Release?

A candle flame burns wax vapor, and incomplete combustion produces fine particles (PM2.5), ultrafine particles smaller than 0.1 micrometers, soot made of black carbon, and small amounts of gases such as nitrogen dioxide, carbon monoxide, and volatile organic compounds. Scented candles also release fragrance chemicals, some of which can react with ozone indoors to form additional particles and formaldehyde. Emissions rise sharply when a flame flickers or smokes, which happens when wicks are too long, candles burn in a draft, or wax tunnels unevenly. A steady, calm flame produces far fewer particles than a sooty, flickering one.

How Much Do Candles Add to Indoor Pollution?

More than many people expect. A 2013 study in Environmental Science & Technology by Gabriel Bekö and colleagues continuously measured ultrafine particles for about 45 hours in 56 homes of nonsmokers in Copenhagen, Denmark. Activities such as candle burning, cooking, and toasting were responsible for most residential exposure. Candles were burned in half the homes, and in those homes they accounted for almost 60 percent of the residents’ integrated ultrafine particle exposure. Concentrations were highest when people were home and awake and lowest when homes were empty or occupants were asleep, showing how strongly daily activities shape indoor air.

Do Candles Harm Health?

The evidence points to small, short-term effects at most for typical use. A 2014 risk assessment in Regulatory Toxicology and Pharmacology by Thomas Petry and colleagues measured emissions from scented candles in test chambers and modeled concentrations in a typical European home. They concluded that under normal conditions of use, scented candles do not pose known health risks to consumers. The analysis relied partly on an exposure model developed by the fragrance industry’s research institute, which is worth keeping in mind. A 2014 randomized, sham-controlled exposure study by Vanessa Soppa and colleagues exposed 55 healthy volunteers to particles from burning candles, toasting bread, and frying sausages for two hours. Overall comparisons showed no clear effect, but in adjusted analyses, higher fine particle levels from candles were associated with small decreases in lung function four hours later. A 2026 double-blind crossover study in the Journal of Breath Research by Laursen and colleagues exposed 17 young adults with mild asthma to emissions from two candle types for five hours and found exhaled breath markers suggesting short-term airway inflammation, particularly after the higher-emitting candle.

Why Were Lead Wicks Banned?

Some candles once used wicks with a metal core, sometimes containing lead, to keep the wick upright. A 2002 study in Science of the Total Environment by Shirley Wasson and colleagues at the EPA found that burning a single candle with a lead-core wick could raise lead concentrations in a room above the EPA’s outdoor air standard, and burning several could exceed workplace exposure limits. Because lead is especially harmful to children’s developing brains, the U.S. Consumer Product Safety Commission banned the sale of candles with lead-cored wicks in 2003. Today most candles use cotton, paper, or wooden wicks, though imported or very old candles may still be worth checking; a wick with a shiny metal core that leaves a gray mark on paper may contain metal.

Are Beeswax Candles Healthier Than Paraffin?

Possibly somewhat cleaner, but the evidence is thin. Paraffin wax is made from petroleum, while beeswax comes from honeycomb and soy and other vegetable waxes from plant oils. Some laboratory comparisons and manufacturer tests have reported lower soot from beeswax and soy candles, and beeswax burns at a higher temperature and more slowly. However, independent, peer-reviewed studies directly comparing health-relevant emissions across wax types are limited, and studies show that wick design, flame stability, and additives often matter as much as the wax itself. Claims that beeswax candles “purify” the air by releasing negative ions are not supported by evidence; any burning candle adds particles rather than removing them.

Do Scented Candles Cause Problems?

For some people, yes. Fragrance compounds can trigger headaches, sneezing, or breathing symptoms in sensitive individuals, including some people with asthma or migraine. Terpenes such as limonene, common in citrus and pine scents, react with indoor ozone to form fine particles and formaldehyde. Unscented candles avoid these extra emissions. People who notice symptoms around scented candles, air fresheners, or incense can switch to unscented candles, use them less often, or choose flameless alternatives such as LED candles for ambiance.

Why Does Long-Term Particle Exposure Matter?

Fine particles are linked to heart and lung disease when exposure is sustained. A landmark 2002 study in JAMA by C. Arden Pope and colleagues followed about 500,000 American adults and found that each 10-microgram increase in long-term outdoor fine particle levels was associated with roughly 4, 6, and 8 percent higher risks of death from all causes, heart and lung disease, and lung cancer, respectively. That research concerned outdoor air over many years, not occasional candle use, but it explains why air scientists pay attention to indoor sources that add to total particle exposure, particularly for people who spend most of their time at home, children, older adults, and those with asthma or heart disease.

Are Incense and Candles Similar?

Incense generally produces much more smoke and particles than candles. A 2019 study in Environment International by Dan Norbäck and colleagues surveyed 39,782 preschool children in seven Chinese cities and found that burning incense at home was associated with more current wheeze and rhinitis, and burning mosquito coils with more asthma and eczema, alongside other indoor and outdoor pollution sources. Families with young children or anyone with asthma may want to limit incense and other smoky sources, use them in well-ventilated spaces, or choose alternatives.

How Do Candle Choices Compare?

How Can You Burn Candles More Cleanly?

A few habits make a large difference. Trim the wick to about a quarter inch before each use, because long wicks produce larger flames and more soot. Keep candles away from drafts, fans, and open windows that make flames flicker. Burn candles long enough for the wax to melt evenly across the top to prevent tunneling, but extinguish them when the flame becomes tall or smoky. Snuff candles rather than blowing them out to reduce the burst of smoke. Ventilate the room by cracking a window or running a kitchen or bathroom fan, and avoid burning many candles at once in small, closed spaces such as bedrooms.

How Do Candles Compare With Cooking and Other Indoor Sources?

Candles are one of several everyday sources. In the Danish study, cooking, toasting, and other activities together with candles accounted for most residential ultrafine particle exposure, and gas stoves, frying, and toasters can produce large bursts of particles. Fireplaces and wood stoves release far more particles than candles, and tobacco smoke remains the most harmful common indoor source. Outdoor pollution also enters homes. Seeing candles as one piece of overall indoor air quality helps put them in perspective: running a range hood while cooking, avoiding indoor smoking, maintaining heating systems, and ventilating regularly often matter more than switching wax types.

Does Winter Make Candle Pollution Worse?

Often, yes. During cold months, homes are sealed more tightly, windows stay closed, and people spend more time indoors, so pollutants from candles, cooking, and heating build up more easily. Holidays also bring more candles, incense, fireplaces, and baking. Newer energy-efficient homes with low air exchange rates can trap particles longer unless they have mechanical ventilation. Briefly opening windows, using exhaust fans, and running a HEPA air purifier during and after candle use help keep winter indoor air cleaner without giving up seasonal traditions.

What Should You Know About Wicks Today?

Wick choice affects how cleanly a candle burns. Most modern wicks are braided cotton or paper, sometimes with a thin zinc or tin core to keep them upright in container candles; these metals are not considered a lead-like hazard at the amounts used. Wooden wicks give a crackling sound and a wide flame and can burn cleanly when properly sized. A wick that is too large for the candle’s diameter produces a tall, smoky flame and more soot, while one that is too small drowns in wax and tunnels. Reputable candle makers test wick sizes for each product. If a candle consistently smokes even after trimming, the wick may be mismatched, and it is better to switch products than to keep burning it.

Do Essential Oil Candles Burn Differently?

Candles scented with essential oils rather than synthetic fragrance are often marketed as healthier, but essential oils are complex mixtures of volatile compounds, including terpenes such as limonene and pinene, which react with ozone indoors just like synthetic fragrance ingredients. Some essential oils are also common skin and respiratory irritants. “Natural” scent does not mean fewer emissions, and heavily scented candles of any kind add more volatile compounds to the air than unscented ones.

Are Soy Candles a Good Middle Ground?

Soy and other vegetable wax candles are popular as a renewable, lower-cost alternative to beeswax. They tend to burn at a lower temperature than paraffin and are often marketed as producing less soot, although, as with beeswax, robust independent comparisons are limited. Many “soy” candles are blends that include paraffin, and soy wax is frequently heavily scented, which can offset any advantage in particle emissions. Reading labels for full ingredient disclosure and choosing lightly scented or unscented products makes more difference than the wax category alone.

Who Should Be Most Careful With Candles?

People with asthma, chronic lung disease, or heart disease are most likely to notice effects from added indoor particles, as are infants and young children, whose lungs are still developing and who breathe more air per pound of body weight. Pet birds are especially sensitive to airborne fumes and smoke, and veterinarians often advise keeping them away from candles, incense, and cooking fumes. Pregnant people may also choose to limit smoky indoor sources. For these households, unscented candles used occasionally in ventilated rooms, or flameless alternatives, are sensible choices.

Can an Air Purifier Help?

Portable air cleaners with true HEPA filters effectively remove fine and ultrafine particles from room air, including candle and cooking smoke, when they are sized for the room and run continuously. They do not remove all gases, though models with activated carbon filters can reduce some odors and volatile compounds. Avoid air cleaners that intentionally generate ozone, which can react with fragrance chemicals to form additional pollutants. Ventilation and source control, burning fewer candles and keeping flames steady, remain the first steps; purifiers are a useful addition, particularly in winter.

How Can You Choose a Good Beeswax Candle?

If you prefer beeswax, look for products labeled 100 percent beeswax, since many candles described as “beeswax” are blends with paraffin or other waxes. Natural beeswax ranges from creamy white to deep gold and has a mild honey scent without added fragrance. Cotton or paper wicks of an appropriate size for the candle’s diameter help it burn evenly. Buying from local beekeepers or producers who disclose ingredients supports transparency. Keep in mind that beeswax is a by-product of honey production, so supply and price vary, and that even pure beeswax candles produce some particles when burned.

What About Fire Safety During the Holidays?

Candle fires are a well-known holiday hazard, with December typically the peak month for home candle fires in the United States according to fire safety organizations. Never leave a burning candle unattended or burn it while sleeping, keep candles at least 12 inches from anything that can burn, including curtains, decorations, and trees, use sturdy holders on stable surfaces, and keep candles out of reach of children and pets. LED candles offer the look without the fire risk, which makes them a good choice for windows, trees, and children’s rooms.

Common Myths

“Beeswax candles clean the air.” Any burning candle adds particles; claims of air purification are not supported.

“Candles are as harmful as smoking.” Typical candle use produces far less pollution than tobacco smoke.

“Natural wax means no emissions.” All waxes produce particles when burned; flame stability matters a lot.

“Lead wicks are still common.” Lead-core wicks have been banned in the U.S. since 2003.

“Scented candles are always dangerous.” Normal use is not considered a known risk for most people, though some are sensitive to fragrance.

Key Terms

PM2.5: Fine particles 2.5 micrometers or smaller that can reach deep into the lungs.

Ultrafine particles: Particles smaller than 0.1 micrometers, produced in large numbers by flames.

Soot: Black carbon particles from incomplete combustion.

Volatile organic compounds (VOCs): Carbon-based chemicals that evaporate into the air, including many fragrance ingredients.

HEPA filter: A high-efficiency filter that captures most airborne particles.

The Bottom Line

Burning candles adds fine and ultrafine particles to indoor air, and in homes that burn them, candles can be the largest source of ultrafine particle exposure. For most people, occasional candle use is not considered a known health risk, though controlled studies show small, short-term effects on the lungs and airways, especially in people with asthma. Beeswax and soy candles may produce less soot than some paraffin candles, but evidence is limited, and wick care, steady flames, ventilation, and avoiding heavy fragrance matter at least as much as wax type. Lead-core wicks have been banned since 2003.

Frequently Asked Questions

Are candles bad for your health?

Occasional candle use is not considered a known health risk for most people, but candles release fine and ultrafine particles and some gases. In Danish homes that burned candles, they accounted for almost 60 percent of ultrafine particle exposure. People with asthma or heart and lung disease, infants, and pet birds are most sensitive, so ventilation and limited use are wise.

Are beeswax candles healthier than paraffin?

Beeswax candles may produce less soot than some paraffin candles, but independent studies comparing wax types are limited, and wick design and flame stability strongly affect emissions. Claims that beeswax purifies the air are not supported. If you choose beeswax, look for 100 percent beeswax with a cotton or paper wick.

Are scented candles toxic?

A risk assessment found scented candles do not pose known health risks under normal use, though it relied partly on an industry exposure model. Fragrance compounds can trigger headaches or breathing symptoms in sensitive people and can react with ozone to form particles and formaldehyde. Unscented candles avoid these added emissions.

Do candles still contain lead?

Candles with lead-core wicks were banned in the United States in 2003 after research showed they could raise indoor lead levels above outdoor air standards. Most candles today use cotton, paper, or wooden wicks. Very old or unregulated imported candles with metal-core wicks are worth avoiding.

How can I reduce candle smoke indoors?

Trim wicks to about a quarter inch, keep candles away from drafts, extinguish them if the flame becomes tall or smoky, snuff rather than blow them out, and ventilate the room with an open window or exhaust fan. A HEPA air purifier can remove remaining particles. Flameless LED candles eliminate emissions entirely.

References

1. Bekö G, Weschler CJ, Wierzbicka A, et al. Ultrafine particles: exposure and source apportionment in 56 Danish homes. Environmental Science & Technology. 2013;47(18):10240–10248. PMID 23957328
2. Petry T, Vitale D, Joachim FJ, et al. Human health risk evaluation of selected VOC, SVOC and particulate emissions from scented candles. Regulatory Toxicology and Pharmacology. 2014;69(1):55–70. PMID 24582651
3. Soppa VJ, Schins RP, Hennig F, et al. Respiratory effects of fine and ultrafine particles from indoor sources: a randomized sham-controlled exposure study of healthy volunteers. International Journal of Environmental Research and Public Health. 2014;11(7):6871–6889. PMID 25000149
4. Laursen KR, Woodland T, Schaber C, et al. Investigating short-term lung inflammation using exhaled breath VOCs from exposure to candles: a randomized controlled crossover study. Journal of Breath Research. 2026;20(2). PMID 42055014
5. Wasson SJ, Guo Z, McBrian JA, et al. Lead in candle emissions. Science of the Total Environment. 2002;296(1–3):159–174. PMID 12398334
6. Pope CA 3rd, Burnett RT, Thun MJ, et al. Lung cancer, cardiopulmonary mortality, and long-term exposure to fine particulate air pollution. JAMA. 2002;287(9):1132–1141. PMID 11879110
7. Norbäck D, Lu C, Zhang Y, et al. Sources of indoor particulate matter (PM) and outdoor air pollution in China in relation to asthma, wheeze, rhinitis and eczema among pre-school children. Environment International. 2019;125:252–260. PMID 30731375

Last updated: October 10, 2026