Are Scented Candles Safe? Experts Weigh In

The flicker of a candle flame has long been associated with relaxation and intimacy. In recent years, however, the humble candle has transcended its traditional role, becoming a significant player in the global home fragrance market. In Europe alone, households purchase an average of 5 to 15 candles annually, with consumption peaking during the autumn and winter months.

This surge is driven by a shift in consumer behavior. "The candles are in fashion," confirms Miguel Bartolomé, Marketing & Communication manager of Isolée. He notes that this boom reflects not just an aesthetic trend, but an evolution of perfume into broader sensory experiences, where scent integrates into domestic space as part of a lifestyle. Yet, as the demand for these atmospheric accessories grows, so does a critical conversation regarding their impact on health and indoor air quality.

The diversification of the candle market is evident in the sheer variety of products available today. The trend has moved far beyond simple tea lights, expanding into substantial decorative pieces. Weights now range from a delicate 70g to impressive 2.8kg vessels, a format utilized by heritage brands like Trudon, recognized as the oldest active candle maker in the world.

This expansion mirrors a broader cultural shift toward "olfactory design," where consumers curate their living spaces not just visually, but through scent. The industry has responded with a vast array of aromas and compositions, turning candles into essential tools for creating specific moods and environments within the home.

• Annual consumption in Europe: 5-15 units per household
• Peak purchasing seasons: Autumn and Winter
• Weight range: 70g to 2.8kg
• Leading heritage brand: Trudon

While the aesthetic appeal is undeniable, the chemistry of burning candles has drawn scrutiny from environmental and medical experts. "There are experimental studies and indoor air quality research showing that certain candles—especially scented ones and those made with paraffin—can emit pollutants when burned," explains Dr. Juan Bertó Botella, a pulmonologist at Clínica Universidad de Navarra.

These findings have been documented in journals of environmental toxicology and indoor air quality, and have been reviewed by major bodies such as the U.S. Environmental Protection Agency (EPA) and the World Health Organization (WHO) regarding indoor pollution. A study published in Scientific Reports demonstrated that lighting a scented candle releases particulate matter that remains suspended in the air and disperses over several meters, sometimes exceeding reference values for indoor air quality.

"There are experimental studies and indoor air quality research showing that certain candles—especially scented ones and those made with paraffin—can emit pollutants when burned."

Not all candles are created equal. The specific composition of the fuel and additives plays a crucial role in the emissions profile. Research published in Environmental Science & Technology confirms that the chemical composition of emissions varies significantly based on the wax type, the wick material, and the aromatic additives used.

This highlights that the quality of the product is a determining factor in its safety profile. While paraffin wax—a petroleum byproduct—is often cited in studies regarding emissions, natural alternatives exist. However, the interaction between the wick, the wax, and the fragrance oil creates a complex combustion process that can introduce various compounds into the air.

• Wax composition (paraffin vs. natural)
• Wick material (cotton, wood, or metal-core)
• Essential oils and synthetic fragrances
• Burning duration and ventilation

Despite the presence of particulate matter, the immediate health risk for the average consumer remains nuanced. Dr. Bertó Botella offers a balanced perspective: "The available evidence does not indicate that occasional candle use poses a serious risk to the general population."

However, he cautions that regular use can contribute to the overall burden of indoor air pollution. "They can contribute, under certain circumstances, to increasing the contaminant load of indoor air," he concludes. This suggests that while a single evening of candlelight is unlikely to cause harm, long-term, frequent use—particularly in spaces with poor ventilation—may warrant caution for those with respiratory sensitivities or pre-existing conditions.

"The available evidence does not indicate that occasional candle use poses a serious risk to the general population."

The allure of scented candles is rooted in their ability to transform a space instantly, engaging the sense of smell to evoke memory and emotion. As the market continues to grow, driven by brands like Isolée and Trudon, the conversation around their safety is likely to evolve alongside scientific understanding.

For consumers, the takeaway is one of informed moderation. By choosing high-quality products and ensuring proper ventilation, enthusiasts can continue to enjoy the sensory benefits of candles while minimizing potential risks. The flame remains a symbol of warmth and comfort, provided it is tended with awareness.