Connecting Composition to Reactivity for Fragrances and Their Emissions

Volatile consumer products (VCPs) include personal care products, cleaning agents and air fresheners. VCPs account for increasing percentages of the anthropogenic volatile organic compound (VOC) load, with the share approaching 50% in some densely populated locales. VCPs are consequently significant contributors to particulate pollution. As the chemical make-up of VCPs is often proprietary or undisclosed by manufacturers, there is growing interest in assessing the composition of such VCPs and working to understand their contribution to air pollution.

In this study, 11 concentrated fragrances were analyzed and their evaporation modeled. Composition was measured by Gas Chromatography-Mass Spectrometry (GC-MS) and Flame Ionization Detection (FID). Between 2 and 9 compounds were identified per fragrance, and the quantified components ranged from 25-93% of the total mass. Evaporation of each fragrance was modeled based on their composition, assuming indoor conditions, i.e. lack of wind. Besides the fragrances' overall VOC contribution, emitted hydroxyl (OHR) and ozone (O₃R) reactivity were also estimated. We find that overall VOC emissions and impacts on OHR and O₃R are driven mostly by terpenes (particularly limonene). Most volatile components evaporate within a day, with emissions decreasing markedly over this time. Due to terpenes' high-volatility and reactivity, the overwhelming majority of reactivity emission occurs in the first few hours of evaporation. Due to varying fragrance formulations, both the total possible reactivity and the amount of reactivity after evaporating over the course of a day may differ by an order of magnitude. Consequently, detailed composition analyses such as those presented here are critical for estimating the growing influence that consumer products exert on aerosol formation and air pollution in urban areas.