All those indoor air fresheners we like to plug in to make our houses smell better are actually pretty bad for the environment. They could have profound health implications for humans breathing in the nanosized particles they release. It all comes down to indoor pollution—words that probably don’t always make much sense.
After all, how can the air inside be polluted unless you’re doing something crazy, like running a propane-powered cooker in a closed-off space? Well, as it actually stands, pollution is a pretty big deal everywhere—inside and outside.
While it’s easy to chalk air pollution up to factories and car exhaust, the little air fresheners that you turn on to make your home smell better are actually pretty high on the list, too, scientists say. According to a new study published by researchers at Purdue University, scented products are a significant source of nanosized particles that can pose a potential risk to respiratory health.
While scented wax melts are marketed as flameless, smoke-free, and even non-toxic alternatives to more traditional candles that burn, they aren’t always a safer way to make your home or office smell better. To see just how much these scented air fresheners can affect indoor air quality, researchers observed them inside a tiny, mechanically ventilated test house.
To start, they measured the nanoparticles that formed when warming wax melts. The house is actually the Purdue Zero Energy Design Guidance for Engineers (zEDGE) lab, an architectural engineering lab designed to test the energy efficiency of a much larger building. As such, it’s loaded with sensors that can help detect indoor pollution levels.
The researchers already knew from previous research that terpenes—aromatic compounds released from melts that react with the indoor atmosphere—are responsible for new nanoparticle formation. However, this new research shows that nanoparticle formation increases significantly when heating wax melts.
This means that a higher concentrated number of nanoparticles—particularly those smaller than 100 nanometers (nm)—are created when you melt a wax melt to enhance the smell of your home. These concentrations are comparable to the indoor pollution caused by diesel engines, gas stoves, and even traditional candles.
The particle formation particularly seems to be driven by the aromatic nature of the melts, too, as melting unscented wax melts did not result in any significant terpene emissions. But why does any of this matter?
Well, it matters because indoor pollution is a huge problem for humans, as polluting the space inside of our homes can lead to increased potential for respiratory issues such as infections. Understanding what can cause these issues is important, too, as is knowing that scented air fresheners play a large part in altering the chemistry of the air in our homes.
Understanding all of that will help us devise better ways to protect the atmospheres within our homes and, in turn, ourselves.
