While most of us are aware of outdoor air pollution, many of us consider our homes a safe, pollution-free zone where our lungs are protected from toxic fumes and chemicals. According to a new study conducted by Purdue University, however, the air inside our homes is actually more polluted than the air outside—simply due to chemical products we use every day.
“When you walk through a pine forest, the crisp, fresh scent is one of the first things you notice,” the study says. “But bringing that pine scent or other aromas indoors with the help of chemical products—yes, air fresheners, wax melts, floor cleaners, deodorants, and others—rapidly fills the air with nanoscale particles that are small enough to get deep into your lungs, Purdue University engineers have found over a series of studies.” And while these findings might put a damper on your favorite scents to diffuse around the house, understanding the science behind indoor air quality—as well as actionable ways to improve it—can help keep us safe.
- Michelle Whitmer is an asbestos and environmental expert with the Mesothelioma Center at Asbestos.com
The Science Behind Indoor Air Quality
One major factor impacting indoor air quality is chemical compounds called terpenes, explains Michelle Whitmer, asbestos and environmental expert. “Terpenes are aromatic compounds that give many plants their smell and flavor,” she says. “These terpenes can react with indoor atmospheric ozone to form nanoparticles that float in the air; nanoparticles are tiny particles that are one billionth of a meter in size.” Because these compounds are so small, they’re quickly absorbed from the air into our lungs.
Unfortunately, nanoparticles can largely form in scent-releasing products such as wax melts. In fact, “a 2016 study found that U.S. indoor dust consistently contains chemicals from multiple classes,” Whitmer notes. “A 2024 study found that essential oil diffusers, disinfectants, air fresheners, and other scented sprays produce a significant amount of nanoparticles as well,” she explains. “The compounds in these products and how they interact with other compounds in the air contribute to the resulting toxicity.” Although research regarding how these volatile chemicals affect our lungs is little to none, the consensus is to be vigilant about products containing nanoparticles because of the effects that may have.
How to Improve Indoor Air Quality
Although curbing our use of scented products might be hard to do, Whitmer offers a few suggestions for improving indoor air quality and limiting how often we use these products.
Open Windows and Doors Regularly
Besides getting a breath of fresh air, Whitmer suggests opening windows and doors regularly to allow toxic fumes to exit the home naturally. “This is especially important when cooking, cleaning or using products that release fumes,” she says.
Use Exhaust Fans in the Kitchen and Bathroom
Cooking (especially if you have a gas stovetop) is a source of indoor air pollution. When cooking, make use of a built-in exhaust fan to help remove pollutants at their source, Whitmer explains.
Opt for Fragrance-Free Products
To decrease the likelihood of inhaling toxic fumes, consider opting for fragrance-free cleaning products.
Limit Use of Air Fresheners, Scented Candles, and Wax Melts
It may be hard to limit your use of air fresheners, scented candles, and wax melts, especially when you’re trying to create a cozy vibe for your space. However, the chemicals used to produce these products can have lasting, detrimental effects.
Dust and Vacuum Regularly
Dusting and vacuuming regularly is one of the simplest, habit-forming ways to improve indoor air quality. “Regularly dusting and vacuuming helps remove dust and particulate matter that can carry pollutants,” Whitmer explains.
Use Air Purifiers and Dehumidifiers
“Controlling moisture levels can prevent mold growth, which can be a significant source of indoor air pollution,” Whitmer says. To do so, consider getting a dehumidifier if your home has high humidity, especially in the summer. Then, regularly turn on an air purifier to help clear the air. “Using an air purifier with a HEPA filter can remove many airborne particles.”