Humans produce an ‘oxidation field’ and it changes the chemical composition of the air around us

(ORDO NEWS) — There are all kinds of pollutants in the air around us. Outdoors, they can be washed away by rain, as well as by oxidation, which occurs when the sun’s ultraviolet light interacts with ozone and water vapor. But what happens in the room?

Oxidation also happens indoors, a new study shows: chemical scavenging that happens with hydroxyl (OH) radicals short-lived reactive species whose job it is to oxidize other molecules comes from a combination of ozone seeping in from the outside and oxidation fields that we create around us.

In some scenarios, indoor levels of OH radicals are comparable to daytime outdoor levels, the scientists found. In other words, we are walking, breathing, chemically reacting machines, with implications for indoor air quality and human health.

“The discovery that we humans are not only a source of chemically active substances, but also capable of transforming these substances ourselves, was very unexpected for us,” says atmospheric chemist Nora Zannoni from the Institute of Atmospheric Sciences and Climate in Italy.

The team conducted experiments with three separate groups of four in a special climate-controlled chamber where ozone levels were at the upper end of what you would normally find indoors. OH values ​​were recorded both with and without ozone, and before and after people entered the room.

Through a combination of computational fluid dynamics simulations and actual air measurements (partially using mass spectrometry techniques), it became clear that OH radicals are present, abundant, and formed around people.

Scientists have discovered that our personal oxidation fields are formed by the reaction of ozone with the oils and fats on our skin – especially the unsaturated triterpene compounds squalene, which make up about 10 percent of lipids, which protect the skin and keep it supple.

“The strength and shape of the oxidation field is determined by how much ozone is present, where it goes, and how the interior is ventilated,” says Zannoni.

It is believed that we spend about 90 percent of our time indoors, and these results are essential to ensure that we spend this time breathing the cleanest and most healthy air, which we are all now very aware of thanks to the pandemic.

Although we have always known that oxidative processes occur indoors, it appears that under some conditions, human-induced reactions are dominant.

It is important to understand these processes, both individually and in relation to other indoor chemicals that can originate from building materials, furniture, and scented products, as the reactions can create respiratory irritants as well as remove contaminants.

Scientists still have a lot of work to do: for example, they want to understand how humidity levels affect reactions, and how more people in a room can change the picture.

In addition, there is a possibility that human-generated oxidation fields may even affect our perception of odors.

“We need to rethink indoor chemistry because the oxidation field we create is transforming many chemicals in our immediate vicinity,” says atmospheric chemist Jonathan Williams of the Max Planck Institute for Chemistry in Germany.


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