New research discovers that scented wax melts, typically considered a safer alternative to candles, can emit harmful nanoparticles. This revelation could reshape how we perceive indoor air quality and the products we use.
Scented wax melts, widely marketed as safer alternatives to traditional candles, might not be as harmless as previously believed, according to new research led by Purdue University and published in ACS’ Environmental Science & Technology Letters.
In a comprehensive study conducted by Nusrat Jung, Brandon Boor and colleagues, the researchers delved into the effects of scented wax melts on indoor air quality.
Previous research indicated that these scented wax melts emit higher levels of airborne scent compounds compared to traditional candles. The team discovered that the volatile organic compounds (VOCs) released by these melts can react with indoor ozone, forming potentially toxic nanoparticles.
The nanoparticles produced by scented wax melts are similar in size to those generated by traditional combustion-based candles, the researchers noted. This was observed through experiments conducted in a full-scale house model, which simulated typical residential settings.
To explore this, the researchers tested 15 different commercially available wax melts, featuring unscented as well as various scented options like lemon, papaya, tangerine and peppermint. They first measured indoor air pollutants without the wax melts, establishing a baseline, and then turned on the wax warmers for about two hours.
Air samples taken at a distance of a few yards from the wax melts revealed airborne nanoparticles ranging from 1 to 100 nanometers wide, comparable to those emitted by traditional candles. These tiny particles pose significant inhalation risks since they can penetrate deep into respiratory tissues and even enter the bloodstream.
The VOCs primarily emitted from the melts were identified as terpenes, including monoterpenes and monoterpenoids. These terpenes, when reacting with ozone, formed adhesive compounds that aggregated into nanoscale particles. Interestingly, no significant emissions or nanoparticle formation were detected in unscented wax melts.
This research is crucial because exposure to high levels of nanoparticles in indoor air has been associated with various health issues, including decreased cognitive function and a higher incidence of childhood asthma.
“[T]his study challenges the perception that scented wax melts are a safer alternative to combustion-based candles,” according to the researchers. However, they also noted the need for more toxicological research to better understand the health risks associated with inhaling nanoparticles from wax melts.
This research could prompt a reassessment of how indoor environments are managed, particularly concerning air quality and the use of popular scented products.