Study reveals scented wax melts are not pollution-free amid claims of safety

A study has determined that emissions from scented wax candle melts release similar nanoparticle concentrations to those of combustion-based scented candles, gas stoves, and diesel engines.

Researchers from Purdue University Indiana, US, report they were inspired by the recent marketing of scented wax melts as a “safer, non-toxic alternative to traditional candles.” 

“Despite being flame-free and smoke-free, scented wax melts can emit quantities of volatile organic compounds larger than those of traditional scented candles due to their higher fragrance concentration and the direct heating of wax, maximizing the melted wax surface area,” says the research. 

Scented wax melts are used for indoor aromatherapy and relaxation. Small chunks of wax are placed in a warmer, releasing specific scents that consumers can personalize and mix to suit their preferences. However, the research says that the emissions from these melts are harmful, and could damage the lungs and heart when inhaled.  

Invisible emissions 

The researchers investigated atmospheric nanoparticle formation alongside the presence of terpene, concluding that emissions released from scented wax melts combine with preexisting atmospheric particles to emit high levels of nanoparticle concentration — similar to that of a diesel engine.

Terpenes are highly aromatic compounds that determine the smell of plants and herbs. They are added to candle wax to create distinct and complex fragrances. 

According to the study, terpenes are released from scented wax melts and react with preexisting atmospheric particles, initiating a new particle formation event that amounts to large concentrations of nanoparticles in the atmosphere. 

Nanoparticles are tiny particles, typically between 1 and 100 nanometers in size. Many materials that are usually not harmful can be toxic if they are in the form of nanoparticles, as their large surface area can penetrate human cells and tissues. 

The study challenges the perception of scented wax melts as a safer alternative to candles, “highlighting the need for further research on the toxicological properties of nanoparticles to better understand their environmental and health implications.”