AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Contextualizing Particles on HVAC Filters
JEFFREY SIEGEL, Juan Pedro Maestre, Ying Xu, Shahana Khurshid, Kerry Kinney, University of Toronto
Abstract Number: 345 Working Group: Indoor Aerosols
Abstract One way of assessing the presence and composition of indoor particles is to collect and analyze samples from heating, ventilation, and air conditioning (HVAC) filters. HVAC filters have been used to reveal the presence of a variety of particle-bound contaminants including fungi and bacteria, viruses, semi-volatile organic compounds (SVOCs), and metals. The promise of the HVAC sampling approach is that it can be used to measure spatially and temporally integrated airborne concentrations of particle-bound contaminants. In order to use HVAC filters to assess the exposure relevant indoor concentrations, the mass of contaminant collected from a filter has to be connected to the average airborne concentration. This presentation provides methodologies to measure the system run-time, air flow rate and filter efficiency that can be used to contextualize HVAC filter samples. For all of these parameters, we present multiple measurement approaches, provide comparisons for the accuracy and usability of each approach, and present measured data. For a sample of approximately 30 homes, we found HVAC run-times that ranged from a few percent (in homes during temperate times of the year) to over 60% in homes during the winter in homes in cold climates. Airflow rates were generally more consistent and ranged from 600 m3/hr for smaller systems to over 2400 m3/hr for larger systems. Manufacturer’s reported filter efficiency was generally an overestimate of in-situ measured filter efficiency, but represented a reasonable estimate of the size resolved efficiency for PM10 and PM2.5. These parameters, in combination with analysis of HVAC filter dust, were then used to assess the airborne concentrations of 36 fungal specifies and several allergens in a subsample of 12 homes. Clear differences in allergen and fungal concentrations were seen in different homes suggesting that it is necessary to characterize HVAC concentrations to use the HVAC filter sampling technique effectively.