An Apparatus for Determination of the Bacterial Content of Air

The Preparation and Measurement of the Concentration of Dilute Bacterial Aerosols.

“…The methods generally used depend either on (I) filtration ( 63), (#) electrostatic sampling (9, 56), (3) bubbling through a liquid, (4) impingement (10, 77), ( 5) centrifugation (92), or (6) some combination of these methods (53,56,64). Filtration appears unsatisfactory, since recovery of viable vegetative organisms is poor (77).…”

“…Electrostatic sampling (9, 56) appears promising, but has not, as far as we know, been carefully compared with other methods. Application of other methods is such that collection is either directly on a solid culture medium (10,56) or into a liquid, from which aliquots are taken for culture (64,74,77), mixed with molten agar, and poured into plates. In either case, colonies are counted after an appropriate period of incubation at a temperature suitable for the organism studied.…”

Studies of Aerosols with a Simple Cloud-Chamber Technic1

“…For the analysis of the concentrations of air-borne bacteria, a number of air-sampling technics (based on two methods of collection) have generally been employed by various investigators. The first includes those devices which collect organisms in a liquid and break up any clumps of bacterial cells, such as the bubbler-pump method of Wheeler et al (1941) and the atomizer-bubbler apparatus of Moulton et al (1943). The second type of sampler impinges the bacteria directly onto a solid medium without attempting to break up clumps and is represented by the Wells' air centrifuge (1933), the funnel device of Hollaender and DallaValle (1939), the slit sampler developed by Bourdillon et al (1941), the sieve device of DuBuy and Crisp (1944) and, more recently, the application of the molecular filter membrane by Goetz (1953).…”

Bacterial Aerosol Samplers

“…Samplers with particular, although limited, merits have been reported. Examples are (a) sedimentation types: open Petri dish and Wells' air centrifuge (Wells, 1933); (b) filtration types: aeroscope (Rettger, 1910), sand tube (Anon, 1942), cotton filter (McConnell and Thomas, 1925), and molecular filter (Goetz, 1953); (c) air washing types: water aeroscope (Rettger, 1910), bead bubbler (Wheeler et al, 1941), atomizer bubbler (Moulton et al, 1943), and Folin-Lemon bubbler (Lemon, 1943); (d) agar impingement types: funnel device (Hollaender and DallaValle, 1939), slit type (Bourdillon et al, 1941), and sieve device (duBuy and Crisp, 1944); (e) electrostatic deposition types: Berry M. E. TYLER AND E. L. SHIPE funnel precipitator (Berry, 1944) and the electrostatic precipitator (Luckiesh et al, 1946a, b). An impingement device with some new features has recently been described (Anderson, 1958).…”