Air is drawn at high speed through a very narrow inlet slit, whereupon particles, including microbes in the air, impact and stick onto an agar surface in a Petri dish.
The Petri dish is slowly rotated under the inlet thus ensuring the air is always impacted onto a fresh area of agar. This dramatically reduces the probability of twin impingement, a phenomena where two microbes land at the same point and appear as a single colony when incubated – this is an issue associated with sieve type samplers.
ImpactAir® high performance slit-to-agar microbial air sampler
The ImpactAir® range uses the larger 14 cm Petri dishes which allow the system to sample for longer periods onto a single dish. The sampling time is programmable from minutes to many hours. With a deep fill agar plate it is possible to sample for several hours onto a single agar plate. Sampling 1 m3 is achieved in 35 minutes and 20 seconds with the flow rate of 1 cubic foot per minute.