Limonene emission dynamics of personal care products from different surface materials

Volatile organic compounds (VOCs) are important precursors to secondary organic aerosol (SOA) and ozone. Fragranced personal care products (PCPs) have been identified as important contributors to VOC emissions in urban and indoor environments, particularly as a source of limonene, which has high SOA mass yields. However, the factors controlling fragranced PCP emission dynamics from different surface types remain unclear. This research quantified the emission dynamics of limonene evaporation from different fragranced PCP types spread across different surface materials. To conduct the study, an equal mass of body wash, lotion, shampoo, and shower scrub was evenly spread across a standardized surface area of glass, silicone, or fabric. The PCP-covered surfaces were placed in a mason jar that was flushed with clean air, and headspace samples were collected every 5-15 minutes on multi-bed adsorbent cartridges. The samples were analyzed via offline thermal desorption gas chromatography-mass spectrometry (TD-GC-MS). Eight different monoterpenoids were identified across all PCP types, with limonene accounting for over 80% of the measured emissions in most products. Limonene also dominated the atmospheric oxidant reactivity of the emissions for all products except body wash, which had a significant oxidant reactivity contribution from linalool. The results illustrate that limonene emission dynamics from PCPs were more dependent on the surface material rather than the type of PCP, where silicone (e.g., permeable material) had the slowest emission rate and served as a limonene reservoir. These results will help improve models of indoor air quality by providing information on VOC emission dynamics from different types of indoor surfaces.