With so many makes and models of air samplers on the market, it is worth looking deeply into the specifications of each before committing to purchase. ISO 14698 Part 1, Annex A part A.3.4.2 recommends the air sampler impact velocity being high enough to allow the entrapment of viable particles down to approximately 1um and being low enough to ensure viability of viable particles as well has having a filtered exhaust.
Following cGMP and ISO 14644-1, the recommended selection criteria below should be used as a guidance in selecting an appropriate portable air sampler or automated air sampling system. Remember that faster flow rate models do not indicate better collection efficiencies. The key factor is the d50, and the criteria for active air sampling in sterile applications is for continuous monitoring during that process. Media can dry out faster under higher flow rates which require more media plate changes.
Knowing the resolution and other features of the air sampler you choose for your process is a critical step in the selection of the right model so you can be confident the results you obtain are reliable and accurate.