Spatial Distributions of Skin Care Products (Fragrances or Lotions) in a Ventilated Room

YOUNGBO WON, Pascale Lakey, Nora Zannoni, Jonathan Williams, Manabu Shiraiwa, Donghyun Rim, Pennsylvania State University

     Abstract Number: 731
     Working Group: Meet the Job Seekers

Abstract
Indoor use of personal skin care products, such as fragrances and lotions, leads to the dispersion of chemical species into the surrounding air. Many of these chemicals interact with indoor reactive species, such as ozone and OH radicals, creating non-uniform spatial distributions of chemical species and reaction products, especially near the human body. This study investigates the spatial distribution of chemical species emitted from personal care products applied by indoor occupants.

The investigation employs a Computational Fluid Dynamics (CFD) model to simulate experimental conditions in a ventilated chamber with four occupants while maintaining an air change rate of 3 h^-1. During the experiments, ozone was introduced at a concentration of 122 ppb, and the time-varying emissions from skin care products and their reaction products were monitored over a 20-minute period.

The results show that when fragrances are applied to the wrists, species such as limonene, monoterpene, and ethanol follow the upward buoyancy airflow around occupants, driven by the occupant's thermal plume, and disperse into the ambient air. The concentrations of these species above the occupants' heads rapidly increase for three minutes and then gradually decrease due to ventilation and reactions. When lotions are applied to the face, neck, arms, and legs, species like ethanol and phenoxyethanol form a candle-like natural convection flow around the occupants, also influenced by the thermal plume effect. The peak concentration of these species occurs 18 minutes after applying the personal care products, with notably higher concentrations observed above the human head and chest, reaching levels 5-6 times greater than those in the ambient air. Overall, this study provides valuable insights into the dispersion and behavior of chemical species from personal care products used indoors, shedding light on the implications for indoor air quality and occupant exposure to these substances.