New Research Shows Scented Cleaning Products Pollute Indoor Air

When we choose cleaning products, we often select them not just for their ability to make things sanitary and sparkly, but also to make them smell good. Many of us associate citrus, pine and floral aromas, for example, with a freshly cleaned room. But a new study conducted by researchers at Purdue University has found that the fragrances in scented cleansers can react with the ozone in indoor air to form nanoparticles “at levels rivaling that of city traffic.”

“Cleaning removes viruses and bacteria from surfaces, but it can also generate invisible air pollution,” Brandon Boor, an assistant professor of civil and construction engineering at Purdue, says in a statement. “There's no visible dust or smoke in the air, but these particles are forming.”

Boor studies indoor air quality and is presenting his team's findings this week at the fall meeting of the American Chemical Society during its “Healthy Indoor Spaces: Bridging the Microbiome and Chemistry” symposium in Chicago.

What did the researchers find?

To study the effect on the air of both conventional and botanical-oil-based scented cleaning products, Boor and his team used scented sprays, liquids and disinfecting wipes in a model “tiny” house — complete with a working kitchen, wood flooring and a bathroom — on Purdue’s campus.

They found that when they mopped, sprayed countertops and wiped down surfaces with scented products, nanoparticles (or ultrafine particles) formed in indoor air more quickly and at higher concentrations than they did in outdoor air.

The finding has health implications because, if inhaled, these invisible pollutants may travel through the airways and “deep into the lungs,” where they can cause respiratory system irritation and inflammation and even “potentially enter the bloodstream,” the researchers say.

“We showed that indoor ozone reactions with fragrances from cleaning produce nanoparticles that carry a respiratory dose comparable to, or greater than, what you would experience from standing outside along a busy road,” Boor says. “The particles are different in terms of their composition, but the total dose can be higher. You're not seeing smoke, dust or haze in the air. Instead, you think the air smells great so it must be clean … But clean air should not smell like highly concentrated citrus fruit. It should not really smell of anything.”

How can you reduce indoor air pollution while cleaning?

The research team says people can reduce exposure to invisible pollutants. Specific steps you can take include:

• Using unscented or low-fragrance cleaning products.
• Avoiding the use of multiple scented products in a cleaning session.
• Opening windows and running exhaust fans to promote ventilation when cleaning.
• Avoiding the use of ozone-generating devices, such as germicidal far-UV (UV-C) lamps, while cleaning.

What cleansers should you use?

We asked Micaela Preston, founder and editor-in-chief of Mindful Momma and author of Practically Green: Your Guide to Eco-Friendly Decision Making, to weigh in.

“I personally prefer and recommend unscented cleaning products,” Preston says, noting that, as the Purdue researchers found, scented cleansers “can be irritating and contribute to indoor air pollution.”

Here are some brands Preston recommends:

• Branch Basics, which offers a fragrance-free, refillable concentrated products and won one of our 2025 Clean Home Awards.
• ATTITUDE, a Canada-based brand that is verified by the independent, health-and-environment-dedicated nonprofit Environmental Working Group (EWG) and won several of this year's Clean Home Awards.
• ECOS, which makes “eco-conscious cleaning products” featuring plant-derived ingredients.
• Molly's Suds, a brand founded by a pediatric nurse that promises to use “only the safest, simplest ingredients available.”
• Blueland, which sells household cleaning products that are “reusable and sustainable" and won several of this year's Clean Home Awards.