Do Candles Cause Indoor Air Pollution? What You Should Know

Candles add a warm glow and comforting scent to any room, making them a popular choice for relaxation and home décor. But as candles burn, they can release harmful chemicals into the indoor air, raising concerns about indoor air pollution. Research shows that scented candles, especially those made from paraffin wax, may emit volatile organic compounds (VOCs), fine particles, and other air pollutants that affect indoor air quality.

While they create a pleasant atmosphere, they may also pose health risks, particularly in poorly ventilated spaces. So, how do candles impact your indoor environment, and what does the scientific literature say about their safety?

When candles burn, the flame causes a chemical reaction that releases volatile organic compounds (VOCs), soot, and other fine particles into the indoor air. These air pollutants can linger in the indoor environment, especially in rooms with poor ventilation.

Some studies have found that burning paraffin wax candles may release small amounts of chemicals like toluene and benzene, though the EPA has not made formal conclusions about their health effects at common indoor exposure levels. Even small amounts of these compounds may contribute to indoor air pollution over time, especially if multiple candles are used often.

The type of wax used in candles plays a major role in how much air pollution they produce. Paraffin wax, made from petroleum, is the most common and also the most polluting. It releases more VOCs and fine particles compared to natural alternatives. Soy, beeswax, coconut, and olive wax candles burn cleaner and produce fewer harmful emissions. These options are often considered better for indoor air quality.

Candle wicks and containers can impact how cleanly a candle burns. Wicks with a metal core—especially older ones with lead—can release heavy metals into the air. Although lead-core wicks are now banned in the U.S., imported or older candles may still contain them.

Burning candles in drafty rooms or containers with poor airflow can lead to incomplete combustion. This causes more soot and increases the number of fine particles in the air, reducing overall indoor air quality.

Labels like “natural” or “eco-friendly” don’t always mean a candle is safe. Many scented candles still contain synthetic fragrances and chemicals that release VOCs when burned. Some companies use greenwashing to make their products seem cleaner than they are.

Even candles with essential oils may include additives or dyes that contribute to indoor air pollutants. Without clear ingredient lists, knowing what you’re breathing in is hard.

Exposure to pollutants from burning candles may affect indoor air quality, which could potentially impact health, especially in sensitive individuals. These effects are more noticeable in people who spend a lot of time indoors or use candles frequently. Some studies suggest that fine particles and VOCs may contribute to irritation or worsen symptoms in people with allergies or respiratory issues.

Common symptoms of exposure include:

• Coughing or throat irritation

• Headaches or dizziness

• Allergy-like symptoms

• Worsened asthma symptoms

• Eye and nose irritation

Ultrafine particles are tiny pollutants released during combustion that are small enough to enter deep into your lungs. Studies from Purdue University and researchers in Denmark found that these particles can even reach the bloodstream, where they may contribute to heart and respiratory problems. Because they are smaller than typical dust or smoke particles, they are harder to filter and more harmful over time, especially in enclosed indoor environments.

Yes, burning candles can worsen health conditions like asthma, especially in sensitive groups. Children, older adults, and people with asthma or other respiratory conditions are more at risk from exposure to candle smoke and indoor air pollutants. Even low levels of indoor air pollutants may contribute to symptoms in people with asthma or respiratory conditions, especially if indoor air quality is already compromised.

Candles don’t have to be completely off-limits. You can still enjoy their scent and glow by following simple steps to reduce the release of indoor air pollutants.

Burning candles occasionally in rooms with proper ventilation helps reduce the buildup of chemicals and particles. Open a window, use a fan, or turn on an air purifier with a HEPA filter to keep indoor air moving and lower pollution levels. This is especially important when using multiple candles or burning them for extended periods.

Keeping the candle wick trimmed to about ¼ inch can prevent the flame from flickering too much and producing more soot. Avoid placing candles near open windows or vents, as drafts cause uneven burning. A steady, low flame burns more cleanly and releases fewer pollutants into the air.

Using candles for shorter periods reduces the total amount of pollution released into your indoor environment. Never leave burning candles unattended, as they pose fire and health risks.

Helpful tips:

• Burn for no more than 1–2 hours at a time

• Extinguish candles if you leave the room

• Choose candles labeled as “clean-burning” or made with natural wax

• Use wax melts or diffusers as smoke-free alternatives

If you love the ambiance and scent of candles but want to protect your indoor air quality, there are safer options. Choosing alternative waxes and fragrance methods can reduce indoor air pollutants while making your home smell great.

Some wax types burn cleaner and release fewer harmful chemicals than traditional paraffin wax. Soy, beeswax, coconut, and olive wax are popular alternatives that help lower indoor air pollution. These waxes produce less soot, fewer volatile organic compounds (VOCs), and reduce exposure to toxic compounds often linked to paraffin-based products.

Fragrance is a major source of indoor air pollutants in scented candles. Many products use synthetic fragrance blends that release chemicals into the air. Instead, look for candles made with essential oils or those labeled as unscented.

These options help limit exposure to artificial compounds and reduce the risk of irritation or allergic reactions. Candles made with essential oils are often marketed as a safer alternative to synthetic fragrances, though they may still release some VOCs when burned.

You don’t need an open flame to enjoy a fresh-smelling home. Simmer pots—made by boiling water with citrus, herbs, or spices—naturally scent the air. Reed diffusers and essential oil diffusers slowly release fragrance without heat or smoke.

Baking soda blended with a few drops of essential oil can absorb odors while leaving a light, clean scent. These smoke-free methods improve your indoor air without adding fine particles or VOCs.

Smart shopping makes a big difference in reducing indoor air pollution. Paying attention to ingredients and certifications helps you choose candles that are safer for your indoor environment.

Read labels carefully when choosing candles. Look for products with lead-free wicks, natural waxes like soy or beeswax, and essential oil-based fragrances. Avoid candles that list “fragrance” or “paraffin” without further details, as these may contain unknown chemicals or produce more soot. Clear labeling is key to understanding what you're burning and how it affects your indoor air.

Certifications can guide you to cleaner, more eco-friendly candles. The USDA Organic seal means the ingredients meet strict organic standards. EcoCert is a global certification that covers sustainability and ingredient safety, and Green Seal focuses on the environmental and health impacts of consumer products. Seeing these on a label is a good sign that the candle is safer for indoor air quality.

To shop smarter, use this quick checklist before buying your next candle:

• Choose natural wax: soy, beeswax, coconut, or olive

• Look for lead-free wicks

• Pick essential oil-based or unscented options

• Avoid paraffin and synthetic fragrances

• Check for trusted eco-certifications

Even if you burn candles occasionally, using an air purifier can help protect your indoor air. The right unit can reduce harmful particles and chemicals from the air while you enjoy your favorite scents.

HEPA filters trap fine particles, including soot and dust, while designed to reduce particles and gases, though their effectiveness can vary depending on the purifier and room size. Together, they reduce exposure to indoor air pollutants and help maintain healthier air quality. Many purifiers are designed to target both particulate matter and chemical emissions, making them a good option for candle users.

Place your air purifier in the same room where you use candles for the best results. Keep it close to the source but not directly next to the flame. Ensure there’s enough space around the unit for airflow, and avoid placing it behind furniture. Running it while the candle is burning and for a short time after will help remove lingering particles and improve your indoor environment.

Candles can still be part of your home routine without compromising indoor air quality—if you choose wisely and burn them responsibly. Using safer waxes, avoiding synthetic fragrances, and making small changes like trimming the wick or improving room ventilation can go a long way in reducing indoor air pollutants. Simple swaps and better habits help keep your indoor environment healthier without giving up the comfort and scent candles bring.