Table 5.

Comparison of non-capture air sampling (^*see also the VeroTect bio-detector and Biral Aspect in Table3)

Sampler/Method	Description	References	Flow Rate (L min−1)	Collection Efficiency d50 (µm)*	Sample period	Analysis method
Any impinger or wet-cyclone	Particles entrained into liquid and analysed optically	Day et al. (2002)	Various	Depends on entrainment method	continuous	Particles entrained into a liquid pass by flow cytometry, an optical sensor that can classify particles according to size, scatter and pigmentation
wide issue bioaerosol spectrometer (WIBS)	optical particle counter with a dual wavelength fluorescence spectrometer	Gabey et al. (2013); Kaye et al. (2005)	<1 (i.e. maximum particle detection rate of 100 Hz (which equates to 40,000 particles /litre)	0.8–20	continuous	Various optical characteristics of individual particles in a narrow air-stream are recorded such as, particle size and symmetry, forward- and side-light scatter, fluorescence and absorbance and used to classify particles. Tryptophan fluorescence is included by excitation at 280 nm, while an illumination pulse at 370 nm is applied to excite NADH fluorescence. Resulting fluorescence in the wave bands 310–400 nm and 400–600 nm is measured.
BioLaz http://www.pmeasuring.com/particleCounter/microbialAirSamplers/BioLaz	Real-time biological particle detector by particle fluorescence		3.6	0.5–50	continuous	405 nm laser excites particles. Fluorescence from biological particles is detected and compared against light scattering caused by all particles to classify biological particles.
Lidar	Non-capture (optical sensing method)	Noh et al. (2013)	N/A	ID range varies with method, generally <50 µm	continuous	Classification based on particle size, shape and pigmentation but relatively imprecise with respect to species of biological particle.

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