The ubiquitous scent of cleanliness associated with household cleaners may come with unforeseen health consequences, according to new research presented by Purdue University.
A study testing scented cleaning products in a model house found that scent compounds quickly react in the air to form nanoparticles. These tiny particles can then build up and travel deep into the lungs, potentially causing respiratory irritation and inflammation, or even entering the bloodstream.
Nanoparticle Formation
The research, presented at the American Chemical Society’s fall meeting, focused on the reactions of terpenes, which are common scent compounds found in many cleaning products, including those with citrus and pine fragrances, as well as botanical essential oils. While terpenes naturally occur outdoors, their concentration is lower, and particle formation is slower. However, when these compounds are used in cleaning products indoors, their airborne levels can become tens to hundreds of times higher than those found in natural environments like forests.
Using a model tiny home, the researchers simulated common cleaning activities such as mopping and spraying countertops. Within minutes, these activities generated billions or trillions of nanoparticles, often in the ultra-fine size range of 1 to 30 nanometers. These particles are frequently too small to be detected by standard at-home air quality monitors but can be detrimental to respiratory health.
"Cleaning removes viruses and bacteria from surfaces, but it can also generate invisible air pollution," said lead study researcher Brandon Boor. "By the time you finish cleaning up an indoor space, you’ve already formed a lot of nanoparticles and inhaled them."
Potential for Worsening Air Quality
The study also indicated that the use of germicidal UV-C lamps for air disinfection could exacerbate the problem. These lamps can create an environment rich for nanoparticle formation by interacting with oxygen and generating ozone. This increased ozone, combined with high terpene levels from scented cleaners, further accelerates particle production.
Boor's previous research during the COVID-19 pandemic also highlighted the impact of cleaning products on indoor environments, finding that the inhalation of aerosols from commercial cleaners could be comparable to or even exceed that of vehicle exhaust.
To mitigate these risks, the researchers suggest opting for low-fragrance or fragrance-free cleaning products. Additionally, ensuring adequate ventilation by running exhaust fans or opening windows while cleaning can help reduce the buildup of these harmful nanoparticles. Boor emphasized that clean air should ideally not have a strong scent, stating, "It should not really smell of anything."