a Chemistry Seminar ft: Nadine Borduas-Dedekind (U of British Columbia)

Authors: Ayomide Akande1, Clemence Depp1, Nadine Borduas-Dedekind1

Affiliation: (1) Department of Chemistry, UBC, Vancouver.

Synthetic musk compounds, like cashmeran, are a group of semi-volatile organic compounds commonly used as fragrances in perfumes. In addition to being potential indoor pollutants, they are also regarded as emerging outdoor pollutants, known at volatile chemical products (VCPs). Cashmeran is a bicyclic synthetic musk compound, and a major component of a commercial perfume for men. Here, we aim to better predict the atmospheric fate of cashmeran indoors and outdoors using a Vocus proton transfer reaction time-of-flight mass spectrometer. 

Using the Vocus, we show that cashmeran was the dominant musk in a commercial perfume among other musk compounds like galaxolide, astratone, and rosamusk. Next,we measured the rate constant of cashmeran (C14H22O) with ozone under different experimental conditions to probe its ozonolysis mechanism. We find that these molecules are slow to react with ozone because of their electron-poor olefins. We then investigated how partitioning sinks might be competitive to gas-phase oxidation for the fate of cashmeran from a commercial perfume in an office environment. We find that partitioning to cotton is the major sink, suggesting this molecule can be easily transported outdoors by humans and their clothing.

We further tested this hypothesis during THE CIX urban field campaign in Toronto, Canada in July-August 2023. We detected cashmeran outdoors throughout the campaign up to 10 ppt. As expected from a fragrant VCP, cashmeran peaked during the week only and in the morning. Based on our findings, we conclude that musk compounds, like cashmeran, are long-lived SVOCs capable of impacting urban air quality.