Interinstrument Variability and Validation Study for the XMX/2L-MIL Biological Air Sampler

The interinstrument variability of the XMX/2L-MIL (XMX) biological air sampler was controlled by operating it with a fixed final nozzle orientation. Three XMXs were operated in a 12-m3 aerosol test chamber (ATC) in which a Bacillus globigii (Bg) aerosol was uniformly distributed for 18 experimental trials. An analysis of variance (ANOVA) was performed on the XMX results and had an Fvalue of 0.36, compared to the F-critical of 3.22 for a p-value of 0.05. This experiment was repeated using male-specific 2 bacteriophage (MS2) viral agent surrogate for 16 experimental trials. An ANOVA was performed on the XMX results and had an Fvalue of 0.09, compared to the F-critical of 3.22 for a p-value of 0.05. Therefore, it was concluded that operating XMXs at the specified final nozzle orientation would lead to precise laboratory culture results with acceptable interinstrument variability. Three XMXs were used to determine if Remel M5(registered trademark) collection media would better preserve MS2 for laboratory culture analysis than the commonly used PBS solution collection media. The XMXs were operated in the ATC in which MS2 aerosol was uniformly distributed for 16 experimental trials, with 8 conducted using Remel M5? and 8 with PBS solution as collection media. An ANOVA was performed on the XMX results and had an F-value of 6.73, compared to the F-critical of 5.30 for a p-value of 0.05. Therefore, it was concluded that Remel M5(registered trademark) produced superior results, as its culture results were 2.3 times greater than those for PBS solution.