Can Scented Candles Affect Indoor Air Quality And What To Avoid

Burning scented candles is a beloved ritual in homes around the world. Their soft glow and inviting fragrances can transform a space, evoke memories, and promote relaxation. However, beneath their comforting allure lies a growing concern: the impact of scented candles on indoor air quality. While many view them as harmless, research shows that certain types of candles release pollutants that may compromise respiratory health and overall well-being—especially with frequent or prolonged use. Understanding what’s released when you light a candle and knowing which products to choose—or avoid—is essential for maintaining a clean, safe indoor environment.

How Scented Candles Impact Indoor Air Quality

When a candle burns, it undergoes combustion—a chemical reaction that produces heat, light, water vapor, carbon dioxide, and various byproducts. The type of wax, wick, and fragrance used determines the nature and quantity of emissions. In poorly ventilated spaces, these byproducts can accumulate, degrading indoor air quality over time.

Common pollutants released during candle burning include:

• Particulate matter (PM2.5): Tiny particles that can penetrate deep into the lungs and even enter the bloodstream.
• Volatile organic compounds (VOCs): Chemicals like benzene, toluene, and formaldehyde, some of which are known carcinogens.
• Carbon monoxide (CO): A colorless, odorless gas produced in incomplete combustion, especially in oxygen-deprived environments.
• Soot: Fine black particles that settle on surfaces and can be inhaled.

A study published in the journal *Atmospheric Environment* found that burning paraffin-based candles significantly increased levels of PM2.5 and VOCs in indoor air. These pollutants are particularly concerning for individuals with asthma, allergies, or other respiratory conditions. Even in healthy individuals, chronic exposure may contribute to irritation of the eyes, nose, and throat, headaches, and fatigue.

Tip: Always burn candles in well-ventilated areas to reduce the concentration of airborne pollutants.

What Ingredients to Avoid in Scented Candles

Not all candles are created equal. The materials used in manufacturing play a critical role in determining how clean or harmful a candle’s burn will be. Below are key ingredients and components to watch out for:

Paraffin Wax

Derived from petroleum, paraffin is the most common candle wax due to its low cost and excellent scent throw. However, when burned, it releases a range of toxic chemicals, including toluene and benzene—both classified as hazardous air pollutants by the U.S. Environmental Protection Agency (EPA). Paraffin also produces more soot than natural waxes, leading to black residue on walls, ceilings, and HVAC systems.

Synthetic Fragrances

Many commercial candles use artificial fragrance oils made from petrochemicals. These often contain phthalates—chemicals used to make scents last longer but linked to endocrine disruption and reproductive issues. Because fragrance formulas are considered trade secrets, manufacturers aren’t required to disclose their full composition, making it difficult for consumers to know exactly what they’re inhaling.

Metal-Core Wicks

Some older or lower-quality candles use wicks with metal cores (often lead or zinc) to keep them upright during burning. Although the U.S. banned lead-core wicks in 2003, they may still appear in imported products. Burning lead-containing wicks releases toxic fumes that can accumulate in the body over time, posing serious neurological risks.

Dyes and Additives

Artificial dyes and stabilizers may enhance appearance but can increase soot production and emit additional VOCs when burned. Some synthetic colorants have been associated with skin sensitivities and respiratory irritation.

“Consumers should treat scented candles like any other aerosol product—they’re essentially diffusing chemicals into the air.” — Dr. Lydia Marks, Indoor Air Quality Researcher, Harvard T.H. Chan School of Public Health

Healthier Alternatives and What to Look For

Choosing safer candles doesn’t mean sacrificing ambiance or aroma. Several cleaner-burning options are available that minimize harmful emissions while delivering a pleasant sensory experience.

Natural Wax Bases

Opt for candles made from renewable, plant-based waxes such as:

• Beeswax: Naturally purifies the air by releasing negative ions that bind to airborne pollutants. It burns cleanly and has a subtle honey-like scent.
• Soy wax: Biodegradable and derived from soybeans, soy wax burns slower and cooler than paraffin, reducing soot and VOC emissions.
• Coconut wax: A sustainable option with excellent scent throw and minimal soot production.
• Palm wax (RSPO-certified): Ensure it’s sourced sustainably to avoid contributing to deforestation.

Cotton or Wood Wicks

Choose candles with 100% cotton or untreated wood wicks. These are free from heavy metals and tend to produce a steady flame with less flickering and soot.

Essential Oil-Based Fragrances

Candles scented with pure essential oils—rather than synthetic fragrance blends—are generally safer. While even natural oils can emit some VOCs when heated, they typically break down more easily in the environment and pose fewer long-term health risks.

Wax Type	Emissions Level	Burn Time	Best For
Paraffin	High (soot, VOCs)	Short to medium	Budget use, occasional burning
Soy	Low to moderate	Long	Daily use, allergy-sensitive homes
Beeswax	Very low	Very long	Air purification, respiratory concerns
Coconut	Low	Long	Luxury candles, strong scent lovers

Tip: Check labels for transparency—brands that list all ingredients (including fragrance sources) are more likely to prioritize safety and sustainability.

Real-Life Scenario: A Family’s Experience with Candle Use

In suburban Denver, the Thompson family began using scented candles daily to create a cozy atmosphere in their living room. Over several months, their youngest daughter, who had no prior history of respiratory issues, started experiencing frequent coughing and nasal congestion, especially in the evenings. After consulting an allergist, they discovered her symptoms worsened during candle-burning sessions.

The family switched to beeswax candles with cotton wicks and eliminated all paraffin-based products. They also began using candles only in well-ventilated areas and limited burn times to one hour at a time. Within three weeks, the child’s symptoms improved significantly. An air quality monitor placed in the living room showed a 60% reduction in PM2.5 levels compared to previous readings.

This case highlights how seemingly minor household habits can have measurable effects on health—particularly in enclosed spaces where pollutants concentrate.

Step-by-Step Guide to Safer Candle Use

Follow this practical sequence to enjoy scented candles without compromising your indoor air quality:

1. Read the label carefully: Look for 100% natural wax (e.g., soy, beeswax, coconut), cotton/wood wicks, and essential oil-based fragrances.
2. Avoid vague terms: Phrases like “premium fragrance” or “exclusive blend” often mask synthetic ingredients.
3. Trim the wick before each use: Keep it at ¼ inch to prevent excessive smoking and uneven burning.
4. Burn in ventilated areas: Open a window slightly or use an exhaust fan to allow fresh air circulation.
5. Limit burn time: Never leave a candle unattended, and cap usage at 3–4 hours per session to prevent overheating and excess emission buildup.
6. Monitor air quality: Consider using an indoor air quality monitor to track PM2.5 and VOC levels, especially if someone in the home has respiratory sensitivities.
7. Store properly: Keep candles in a cool, dark place to preserve wax integrity and fragrance stability.

Checklist: Choosing a Clean-Burning Scented Candle

• ✅ Made with natural wax (soy, beeswax, coconut)
• ✅ Wick is 100% cotton or wood—no metal core
• ✅ Scented with essential oils or clearly labeled safe fragrance oils
• ✅ Free from synthetic dyes and additives
• ✅ Transparent ingredient labeling
• ✅ Hand-poured by a reputable brand with third-party testing
• ✅ Burns cleanly (minimal smoke or soot after 10 minutes)

Frequently Asked Questions

Are all soy candles safe?

Not necessarily. While soy wax itself is a cleaner alternative to paraffin, some manufacturers blend soy with paraffin to cut costs. Additionally, soy candles may still contain synthetic fragrances and dyes. Always verify the purity of the wax and the source of the scent.

Can I make my own safer candles at home?

Yes. DIY candle-making allows full control over ingredients. Use food-grade soy or beeswax, untreated cotton wicks, and high-quality essential oils. Avoid overheating the wax, and ensure proper wick sizing to prevent tunneling and sooting.

Do “natural” or “organic” labels guarantee safety?

Not always. There is no standardized certification for “organic” candles in most countries. The term is often used loosely for marketing. Look for third-party certifications like USDA Organic (for ingredients), or EcoCert, and verify claims through independent reviews or lab reports.

Conclusion: Making Informed Choices for a Healthier Home

Scented candles don’t have to be a hidden hazard in your home. With awareness and mindful selection, you can enjoy their warmth and fragrance while protecting your indoor air quality. The key lies in understanding what goes into your candles—not just the scent, but the wax, wick, and additives. Prioritizing natural materials, transparent brands, and responsible burning practices transforms candle use from a potential risk into a truly holistic ritual.

Every breath matters, especially in the spaces where you live, relax, and recharge. By choosing cleaner candles and adopting safer habits, you’re not just enhancing ambiance—you’re investing in long-term health for yourself and your loved ones.

🚀 Ready to refresh your candle collection? Start by replacing one paraffin candle with a clean-burning alternative today—and breathe easier tonight.