AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Modeling the Impact of Residential HVAC Filtration on Indoor PM2.5 of Outdoor Origin and Associated Chronic Health Risks
DAN ZHAO, Parham Azimi, Brent Stephens, Illinois Institute of Technology
Abstract Number: 334 Working Group: Aerosol Exposure
Abstract Because outdoor particles can penetrate indoors where people spend most of their time, much of human exposure to fine particulate matter (PM2.5) of outdoor origin actually occurs inside buildings and in particular, inside residences. High efficiency particle air filters in central heating, ventilating, and air-conditioning (HVAC) systems are increasingly being relied upon to reduce indoor particle concentrations in homes. However, questions remain regarding the effectiveness of central HVAC filtration in reducing indoor PM2.5 of outdoor origin and associated adverse health effects given the wide variations of the underlying mechanisms that govern indoor concentrations of outdoor particles in homes, including differences in envelope construction and HVAC system sizing that influence air exchange rates, HVAC airflow rates, and HVAC system runtimes. Therefore, in this work we modeled the impact of HVAC filtration (from MERV <5 to HEPA) on indoor concentrations of PM2.5 of outdoor origin in three types of residential buildings (i.e., older, existing, and new homes) located in 22 U.S. cities using hourly simulations. Results demonstrate that the average infiltration factor for PM2.5 ranges from 0.4 with a MERV 5 filter to around 0.25 with a HEPA filter in an older, inefficient home with a poorly sealed envelope. The average PM2.5 infiltration factor in typical existing homes ranged from just under 0.20 with a MERV 5 filter to around 0.15 with a HEPA filter. Finally, the average PM2.5 infiltration factor was consistently less than 0.03 with all filters in a typical new home with a very tight envelope. Model results were then combined with various methods to estimate the impact of HVAC filtration on the chronic health risk of PM2.5 of outdoor origin in homes using a variety of models and concentration-response functions from the recent literature.