Personal care products (PCPs), such as soaps and cosmetics, are commonly used indoors and contain many different chemical ingredients.
New research from EPFL shows that these products can significantly impact indoor air quality. They release over 200 volatile organic compounds (VOCs) into the air when used. When these VOCs mix with ozone, they can create new compounds and particles that may reach deep into our lungs. Scientists are still unsure about the effects of regularly inhaling these particles on respiratory health.
The study began with Dusan Licina, an assistant professor at EPFL, and his team creating a shopping list of everyday personal care products like deodorants, lotions, perfumes, and dry shampoo from well-known brands. Licina leads the Human-Oriented Built Environment Lab at the Smart Living Lab in Fribourg, which has extraordinary chambers designed to simulate natural indoor environments and monitor air quality.
Led by Licina’s former postdoc, Tianren Wu, the research team collaborated with researchers from Germany and Sweden to test how these products affect indoor air. In one experiment, they used the products under typical conditions while closely monitoring the air quality.
In another test, they added ozone, a reactive gas that can enter homes through open windows or indoor sources like printers. They used five advanced measuring instruments to analyze the gases and particles in the chamber.
The researchers spent two years analyzing the data they collected. The first test without ozone found that the personal care products released over 200 VOCs, which gradually decreased with ventilation. The most common substances detected were ethanol and monoterpenes, often used in these products.
However, when ozone was added to the chamber, it caused the formation of new VOCs and particles, especially from perfumes and sprays. These levels of pollutants were higher than those found in heavily polluted urban areas like downtown Zurich.
Licina said, “Some molecules’ nucleate’ – in other words, they form new particles that can coagulate into larger ultrafine particles that can effectively deposit into our lungs. We still don’t fully understand the health effects of these pollutants, but they may be more harmful than we think, mainly because they are applied close to our breathing zone. This is an area where new toxicological studies are needed.”
Several strategies can be considered for building design to improve indoor air quality affected by personal care products. These include increasing ventilation—especially when using these products—installing air-cleaning devices like activated carbon filters and limiting indoor ozone levels.
Licina also suggests reducing reliance on these products or switching to more natural alternatives with less reactive fragrant compounds. Additionally, it is important to raise awareness about these issues among medical professionals and those caring for vulnerable groups, such as children and the elderly.
Journal Reference:
- Tianren Wu, Tatjana Müller, Nijing Wang, Joseph Byron, Sarka Langer, Jonathan Williams, and Dusan Licina, “Indoor Emission, Oxidation, and New Particle Formation of Personal Care Product Related Volatile Organic Compounds,” Environmental Science & Technology Letters, 30 August 2024. DOI: 10.1021/acs.estlett.4c00353