There are all kinds of pollutants in the air around us. Outdoors, these pollutants can be washed away by rainfall and oxidation reactions that occur after ultraviolet rays from the sun react with ozone layer and water vapor.
Man-made oxidation field
Some oxidation reactions are also taking place indoors, as new research shows: chemical cleaning by hydroxyl (OH) radicals (short-lived reactive species whose job is to oxidize other molecules) is catalyzed by It is caused by a combination of ozone leaking in and the oxidative field we create around ourselves.
The scientists found that, under certain conditions, indoor OH radical concentrations were comparable to outdoor OH radical concentrations during the day.
In other words, we are walking and breathing chemical reaction machines, which have an impact on indoor air quality and human health.
Dr Nora Zannoni, an atmospheric chemist at the Italian Institute of Atmospheric Sciences and Climate (ISAC), said:
“What we found is that humans are not just a source of reactive chemicals , and the fact that we ourselves are able to convert these chemicals is very surprising to us.”
Experiments and Results
The research team conducted the experiments with three different groups of four, in specially climate-controlled rooms.
In these rooms, the ozone concentration is at the upper end of the concentration normally found in the room. The researchers recorded OH levels with and without ozone, and before and after humans entered the room.
By combining computer-simulated hydrodynamic models with actual measurements of air (in part involving mass spectrometry), the results became clear,
That is, OH radicals appear in large numbers around human beings, and are also formed around human beings.
Scientists have discovered that our personal oxidative field is built up when ozone reacts with the oils and fats on our skin—especially the unsaturated triterpene squalene compound. This triterpene squalene compound makes up 10% of the lipids that protect and soften the skin.
“The strength and shape of the oxidation field is determined by how much ozone is present, where it penetrates, and how the ventilation of the indoor space is configured,” Dr Zanoni said.
It is generally believed that we spend 90% of our time indoors. And the above findings have important implications for ensuring that under those times, we breathe in the cleaner and healthier air possible. This is thanks to the coronavirus pandemic, which we are all acutely aware of now.
Future studies
While we’ve always known that oxidation processes take place indoors, it seems that in some cases, it’s the human-generated reaction that dominates.
It is important to understand these processes, not only in isolation, but also in relation to other indoor chemicals that may arise from building materials, furniture and scented products. This is because chemical reactions can create respiratory irritants and remove contaminants.
There is still a lot of research that must be done. For example, scientists are diligent about understanding how humidity levels affect responses; and how conditions might change when more and more people are in a room. Also, the oxidative fields produced by humans may even affect our perception of odors.
Dr Jonathan Williams, an atmospheric chemist at the Max Planck Institute for Chemistry in Germany, said:
“We have to rethink indoor chemistry that fills the space because we create oxidative fields that alter many chemicals in our vicinity.”
