Human Activities Shape Indoor Volatile Chemistry

Perception of odors created by volatile molecules is central to human well-being. The chemistry of volatile compounds is especially important inside the built environment as humans spend increasingly more time indoors. However, a comprehensive understanding of the composition and behavior of indoor volatile and semivolatile compounds (volatilome) is limited, in part due to the tremendous complexity and fleeting nature of these chemical distributions. This study explored the comprehensive volatilome, as opposed to individual compounds, of the indoor environment of a residence. We mapped a spatial distribution of volatiles within a house and traced corresponding temporal volatilome changes. Each indoor activity generated a trail of volatiles, and the indoor volatilome after human habitation was found to be distinctly reshaped. Using molecular networking, we explored how multiple chemical families were affected. The portion of the volatilome that has accumulated due to human occupancy appears to be more harmful to human health than emissions from the built environment itself. This is an important consideration for any other human environment with accumulated volatile chemistry, such as hospitals or office spaces.