AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Experimental Investigation of the Transport of Surrogate Indoor Bioaerosols from Simulated Human Respiratory Activities and Control by HVAC Filtration in an Unoccupied Apartment Unit
STEPHANIE KUNKEL, Parham Azimi, Haoran Zhao, Brent Stephens, Illinois Institute of Technology
Abstract Number: 224 Working Group: Indoor Aerosols
Abstract Breathing, sneezing, and coughing are important sources of many microbial pathogens, with microbes being aerosolized and dispersed in droplets and droplet nuclei. Knowledge of how this dispersion is affected by recirculation airflow, outdoor air ventilation, particle deposition, and central HVAC filtration is critical to understanding how airborne microbes are spread and potentially controlled. Here we use a custom nebulizer-based human respiratory activity simulator to aerosolize non-pathogenic organisms (mimicking the airborne transmission of pathogenic viruses and bacteria) in an unoccupied test apartment unit. Model organisms include (1) Escherichia coli K12, a gram-negative bacterium (size ~1 µm), as a model for Bordella and Neisseria, and (2) bacteriophage T4, a double-stranded DNA coliphage (~60 nm), as a model for influenza virus. Size-resolved bioaerosol sampling was conducted using Sioutas cascade impactors located in four locations (0.5m, 3m, 5m and 7m from the source). Quantitative PCR was performed to quantify the concentrations of the model organisms found at the various test locations around the room. Test conditions included four different central recirculating HVAC filter conditions: no filter, MERV 8, MERV 11 and MERV 16. The concentration of collected biomass across all bins decreased rapidly with distance from the source. Both organisms were still detected in small amounts up to 7m away under all filtration conditions. There was over a 90% reduction in detection of both organisms in air 3m and 5m from the source with MERV 11 and MERV 16 filters. At the longest distances representing long-range airborne transport, more biomass was found in the larger size bins for the larger E. coli compared to the smaller T4 bacteriophage. Approximately 45% of the E. coli biomass was found in the >1 µm size range in the longest range samples, while only ~13% of the T4 biomass was found in the same size range.