Limonene Emission Dynamics of Personal Care Products from Different Surface Materials

AVISA CHARMCHI, Pascale Lakey, Manabu Shiraiwa, Celia Faiola, University of California, Irvine

     Abstract Number: 201
     Working Group: Indoor Aerosols

Abstract
Volatile organic compounds (VOCs) are important precursors to secondary organic aerosol (SOA) formation. Fragranced personal care products (PCPs) have recently been identified as important contributors to VOC emissions in urban environments, particularly as a source of limonene, which has high SOA mass yields. However, the factors controlling fragranced PCP limonene emissions from various surfaces remain unclear. This research quantified the dynamics of limonene emissions from a variety of different fragranced PCP types and across different types of surface materials. The emission dynamics were measured for 60 minutes at 5-minute intervals from glass, silicone (as a skin proxy), and fabric. The PCP was applied across 34.25 cm² of surface. The sample was then placed in a mason jar equipped with bulkhead unions on the lid, flushed with clean air, and samples were collected at the outlet using multi-bed adsorbent cartridges. The samples were analyzed via offline thermal desorption gas chromatography-mass spectrometry (TDGCMS). The results illustrated that limonene emissions from personal care products were more dependent on the surface material than the type of PCP, with silicone (e.g., “skin-like” material) having the slowest emission rate. In addition, we found that “skin-like” material released less mass of limonene across the measurement interval, suggesting that this material serves as a larger sink for limonene. We applied a kinetic multi-layer kinetic model to replicate the measurements, estimating diffusion coefficients of limonene in personal care products to be in the range of 1.5 x 10^-9 cm²s^-1 – 1 x 10^-6 cm²s^-1. The model also demonstrated that the partitioning of limonene into silicone slowed down its evaporative loss to the gas phase. The dynamics of limonene emissions from PCPs could influence indoor air quality as well as urban air quality. Future studies should evaluate the potential impact of these PCP emission rates on human health.