CFD analysis of ozone reaction with human surface: influence of indoor air flow conditions and surface reactivity

Open Access
Author:
Ananthanarayanan, Sagar Sangameswaran
Graduate Program:
Aerospace Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
June 21, 2016
Committee Members:
  • Donghyun Rim, Thesis Advisor
  • Susan W Stewart, Committee Member
  • George A Lesieutre, Committee Member
Keywords:
  • Ozone
  • CFD
  • Ventilation
  • Indoor Air Quality
Abstract:
Ozone reaction with the human body surface can significantly influence breathing zone ozone concentrations. Human exposure to ozone and its reaction products may also adversely affect health and comfort. Ozone uptake to indoor surfaces has been characterized for many building materials; however, limited information is available on how ozone reaction with human surface is influenced by human surface reactivity and airflow around human body. The objectives of this study are 1) to investigate ozone reaction with human surfaces depending on indoor ventilation conditions; 2) to examine the breathing zone concentration of ozone considering reactivity of human skin oil and clothing; and 3) to explore the effect of reaction probability on ozone mass transfer rate. A computational fluid dynamics (CFD) simulation was verified and validated with previously published chamber experiments. The validated CFD models were applied further to examine the ozone reaction with the human surface in varying airflow conditions. Effects of varying degrees of human surface reactivity on the breathing zone concentration were examined. For typical indoor environments with air change rate < 5 h-1, the ozone mass transfer rate (deposition velocity) was in the range of 8-10 m/h with perfect sink condition. Parametric analysis results reveal that surface reactivity of the human body has a larger influence than air change rate and ventilation pattern. The breathing zone ozone concentration is also strongly influenced by surface reactivity. With a supply ozone concentration of 100 ppb and a transport-limited rate at the human surface (such as human skin oil), the breathing zone concentrations are in the range of 81-97 ppb, while the range is 96-99 ppb with lower surface reaction rate. These results imply that the reaction probability of the human surface has a significant impact on human exposure to ozone and reaction byproducts.