A system for continuous sampling of bioaerosols generated by a postal sorting machine
The mass emission rate of the postal sorting machine was 3.15 mg/min and found not to vary significantly with flow rates above 700 L/min. On average, greater than 66% of the mass collected had a Da < 10 ?m. Using a Coulter Counter, the volume median diameter (volume equivalent) for both device hydrosol outputs was 4.18 ?m. For the effluent aerosol, the volume median diameter was 12.5 ?m.
For a bioaerosol release, this study found that greater than 65% (by volume) of the material released had a Da greater than 7.2 ?m. Using filters, it was found that on average, 95% of the bioaerosol particles emitted had a Da less than 10 ?m. According to the reference data, the expected number of bioaerosol particles in 1.5
times that collected by the GCS and 5.5 times that collected by the JBPDS cyclone for a one milligram release. The time constant for the system in response to a letter release was found to be 1.3 minutes for the GCS and 1.75 minutes for the JBPDS cyclone.
A final note to this study states that the probe dimensions were incorrectly developed, therefore affecting the aspiration efficiency of the probes. In turn, this may have affected the outcome of some of the results. A plot is given at the end of the paper showing to what extent the results may have been affected. It is recommended that further experimental studies be performed to verify the results in this study.
Advisor:McFarland, Andrew; O'Neal, Dennis; Marlow, William
School:Texas A&M University
School Location:USA - Texas
Source Type:Master's Thesis
Keywords:bioaerosol anthrax post office wetted wall cyclone ahts
Date of Publication:08/01/2003