Personal care products affect indoor air quality, warns Swiss study

The study by scientists at the Federal Institute of Technology Lausanne (EFPL) found that when cosmetic products are used indoors and come into contact with ozone, the resulting chemical reactions can produce new compounds and particles that can "penetrate deeply" into the lungs. Credit: Rightdisc / Alamy Stock Photo

A Swiss study claims that typical personal care products can have a ‘significant impact’ on air quality when used in enclosed spaces. When they come into contact with ozone, the products spark chemical reactions generating new air pollutants, researchers found.

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The study by scientists at the Federal Institute of Technology Lausanne (EFPL) found that when cosmetic products are used indoors and come into contact with ozone, the resulting chemical reactions can produce new compounds and particles that can “penetrate deeply” into the lungs.

However, scientists don’t yet know “how inhaling these particles on a daily basis affects our respiratory health”, EPFL said in a press release on Thursday.

The researchExternal link, published in Environmental Science & Technology Letters, was conducted using roll-on deodorant, spray deodorant, hand lotion, perfume and dry shampoo hair spray – all produced by leading brands and available in major stores across Europe and elsewhere. It took the researchers two years to process all the data collected.

Reaction with ozone

In a first test, the scientists applied the products under normal conditions, indoors and without ozone. More than 200 volatile organic compounds (VOCs) were emitted by the cosmetics, before gradually dissipating with ventilation. The most abundant molecules detected were ethanol and monoterpenes, typically those used in these products.

In a second test, the researchers injected ozone, a reactive gas present in the atmosphere during summer in Europe. Ozone can seep into homes through open windows. It can also come from indoors, for example when using laser or 3D printers.

By introducing ozone, not only new VOCs, but also new particles were generated, especially from perfumes and sprays. EPFL says a concentration exceeded those “found in heavily polluted urban areas such as downtown Zurich”.

Effects still poorly understood

“Some molecules ‘nucleate’ – in other words, they form new particles that can coagulate into larger ultrafine particles that can effectively deposit into our lungs,” explains Dusan Licina, who leads EPFL’s Human-Oriented Built Environment LabExternal link (HOBEL) at the Smart Living Lab in Fribourg.

“In my opinion, we still don’t fully understand the health effects of these pollutants, but they may be more harmful than we think, especially because they are applied close to our breathing zone. This is an area where new toxicological studies are needed.”

To limit the effect of personal care products on indoor air quality, we could consider several alternatives for how buildings are engineered: introducing more ventilation – especially during the products’ use – incorporating air-cleaning devices (e.g., activated carbon-based filters combined with media filters), and limiting the concentration of indoor ozone.

Licinia also recommends “reducing our reliance on these products or, if possible, replacing them with more natural alternatives containing odorous compounds with low chemical reactivity.” Another useful measure would be to raise awareness among health professionals and staff working with vulnerable groups, such as children and the elderly.

Translated from French by DeepL/sb

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