Scented cleaning products can spawn invisible nanoparticles that penetrate deep into lungs

Scientists at Purdue University have found that scented cleaning agents, including those based on botanical essential oils, release terpene vapors that react with indoor ozone to generate massive numbers of nanoparticles. In a model house experiment, the reaction produced billions to trillions of particles measuring only 1-30 nanometers, a size that allows them to travel deep into the respiratory tract. The rapid formation—occurring within minutes—means occupants inhale these particles while cleaning, receiving a dose that can equal or exceed exposure near busy roadways.

The effect is amplified when ozone-producing devices like far-UV lamps are operated at the same time, raising indoor ozone to 20-40 ppb and boosting particle formation. Researchers recommend choosing low-fragrance or fragrance-free cleaners, limiting the use of multiple scented products, and ensuring adequate ventilation through fans or open windows to reduce exposure. The work was presented at the American Chemical Society’s Healthy Indoor Spaces symposium and funded by the National Science Foundation and the Alfred P. Sloan Foundation.