. 2015 Jan 19;166(1):4–17. doi: 10.1111/aab.12191

Table 3.

Comparison of commercially available virtual impactors for air sampling

Sampler	Description	References	Flow Rate (L min⁻¹)	Collection Efficiency d50 (µm)^*	Sample period	Compatible with analysis method
Sampler	Description	References	Flow Rate (L min⁻¹)	Collection Efficiency d50 (µm)^*	Sample period	Culture	Microscope	Biosensor/ Molecular
VeroTect bio-detector http://www.biral.com/bio-detectors/biodetectors	Virtual Impactor	Shelton et al. (2004)	33	0.5	Continual
						Aerosol Size And Shape Characterisation and additional generic characterisation by particle fluorescence using 280 nm excitation can provide a simple yes/no indication of biological particles or a more sophisticated analysis package for research use.
Biral Aspect http://www.biral.com/imagprod/downloads/Aspect.pdf	Virtual Impactor	Shelton et al. (2004)	?	?	Continual
						Aspect uses light scattering to measure particle shape as well as size and so is suitable for small particles and high throughput rates than systems that rely on particle imaging.
Burkard Jet spore sampler http://www.burkard.co.uk/jetsamp.htm	Virtual Impactor	Limpert et al. (1999)	850	1–2 (estimate)	Up to several days	Yes	Yes	Yes
Miniature Virtual Impactor (MVI)	Miniature Virtual Impactor	West et al. (2013)	20	2 (estimate)	Up to several days	Yes	Yes	Yes

d50 is the aerodynamic diameter or size of particles above which 50% or more are collected and below which, less than 50% are collected.