A system for continuous sampling of bioaerosols generated by a postal sorting machine

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Title: A system for continuous sampling of bioaerosols generated by a postal sorting machine
Author: Richardson, Mathews Sears
Abstract: In this study , a system for the collection of bioaerosols emitted from the mail sorting process was designed and characterized . Two different wetted -wall cyclones , the JBPDS cyclone and the glass cyclone sampler (GCS ) , were evaluated as system collection devices . These devices operate at 780 L /min and have a D50 of ~ 1 ?m . A trimming impactor with a D50 of 10 ?m was used upstream of the collection devices . Using two reference probes , the cyclone liquid outputs were compared with aerosol collected on filters and the output of an Aerosol -to -Hydrosol Transfer Stage (AHTS ) . 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 .
URI: http : / /hdl .handle .net /1969 .1 /1210
Date: 2004-11-15

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A system for continuous sampling of bioaerosols generated by a postal sorting machine. Available electronically from http : / /hdl .handle .net /1969 .1 /1210 .

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