Selecting an Air Sampler for Bioaerosol Collection
Indoor Air Quality (IAQ) investigators should select cost effective, efficient and the highest quality sampling
equipment for evaluation of indoor environments. Particle impaction onto an adhesive surface (non-viable) or into culture media (viable) are the most widely used techniques to evaluate the presence and levels of airborne bioaerosols, particularly in non-industrial indoor environments. These processes depend on the inertial properties of the particles, such as size, density and velocity, and on the physical parameters of the impactor, such as inlet-nozzle dimensions, jet-to-plate distances and airflow velocities and paths. Because of differences in physical characteristics, samplers differ in collection efficiency, often referred to as “cut-off” size (d50) (e.g., the particle size above which 50% or more of the particles are collected). As most impactors have very sharp cut-off characteristics, most particles larger than the d50 are collected.1,2 No sampler collects all particles with equal efficiency, and it is therefore not surprising that different quantitative and qualitative results are obtained using different sampling devices. IAQ investigators should select Air-O-Cell®, Allergenco-D®, Cyclex®, Cyclex-d® or Micro-5® spore trap cassettes based on their operational characteristics (summarized below). No corresponding studies have been published on Andersen Type viable impactors fabricated by different manufacturers, but as a class, these remain cost effective and efficient
viable samplers for use in IAQ investigations.