What's sticking on my window?

ChemSci Pick of the Week

As people spend 90% of their time indoors, explaining how gases stick and react on surfaces can help improve indoor air quality.

It’s easy to think of air quality as being a problem of the outdoors – vehicles and industrial processes all emit gases and particles that contribute to climate change and pollute the air we breathe. These issues are well known, but the quality of air in indoor environments is less well understood.

"Gases present in the indoor environment – such as from smoke, cooking and personal care products such as fragrances – can stick to any of the surfaces present in indoor environments, including window surfaces", says Professor Vicki Grassian from the University of California. "Thick coatings can form on different surfaces – including glass – which can then undergo chemistry which can lead to the emission of other gases."

Professor Grassian and her team are researching a particular aspect of the indoor atmosphere – the interaction between glass and the types of organic compounds found in indoor environments. They have focused in particular on limonene – the chemical found in the peel of citrus fruits, and also used in household cleaners and air fresheners. They have looked at how limonene interacts with glass, how strong the interaction is, and whether limonene can "unstick" and go back into the gas phase.

"I and my older daughter are both asthmatic", says Professor Grassian. "Smoke and other triggers of asthma indoors has caused trips to the emergency room. Understanding what is in the air we breathe is important to everyone but especially important for people with asthma and other chronic obstructive pulmonary disease.

"Overall, we are interested in unravelling the processes at the molecular scale on the role of surfaces in indoor environments, and ultimately using these details in air quality models."

This article is free to read in our open access, flagship journal Chemical Science: Douglas Tobias, Manabu Shiraiwa, Vicki Grassian et al., Chem. Sci., 2019, Accepted Manuscript. DOI: 10.1039/C8SC05560B. You can access our 2019 ChemSci Picks in this article collection.