AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
How Does Reducing Air Exchange Rate Affect Indoor Microbial Communities and Air Quality?
JUAN PEDRO MAESTRE, Josh Aldred, Wiley Jennings, Shahana Khurshid, Chloe Wooldridge, Atila Novoselac, Kerry Kinney, The University of Texas at Austin
Abstract Number: 416 Working Group: Indoor Aerosols
Abstract Approximately 40% of energy consumption in the U.S. is due to buildings. Lowering ventilation rates can reduce building energy demand, but the impact of these reductions on indoor air quality must be considered. The objective of this study was to determine how decreasing ventilation rates in a building affects contaminant concentrations and the composition of microbial communities present within the building.
The effect of ventilation rate was investigated in a LEED certified building that typically operates at a high air exchange rate (AER). The effect of reducing the AER from 6 h-1 to 4 h-1 was investigated in two indoor spaces: one normally high occupancy room (HOR) and one normally low occupancy room (LOR). Neither room was occupied at the time of sampling. Airborne, settled dust, HVAC filter dust and surface wipe samples were collected to assess the microbial communities present at each ventilation condition. Microbial DNA extracted from the samples was analyzed via qPCR and Illumina sequencing to characterize the bacterial communities present. QIIME and SourceTracker were used to elucidate relationships between communities.
Results indicate that at reduced ventilation rates, indoor ozone concentrations increased by 50% and total VOC concentrations increased by 70%. At both AERs, human-associated taxa were more abundant indoors than outdoors. The HOR had a higher proportion of human-associated bacteria than did the LOR. The diversity of the airborne microbial community in both rooms decreased when the AER was reduced. Interestingly, at both AERs tested, the diversity of the microbial communities were similar in the HOR and the LOR suggesting that at the high ventilation rates investigated in this study, occupancy level is less important than ventilation with respect to microbial diversity. The study results indicate that while some indoor contaminant concentrations increase with reduced ventilation rates, the effects on indoor microbial communities is more complex.