Active Air Sampling Definition

Passive sampling relies on the kinetic energy of gas molecules and diffusion of the gases in an enclosed space onto a sorbent medium.

Active air sampling definition.

During the sampling procedure the air sampler draws a defined air volume through the gelatin filter flow rate selectable between 2 and 8m 3 h. Air sampling is the process of capturing contaminants in a known volume of air. In active monitoring a microbial air sampler is used to force air into or onto its collection medium e g petri dish with nutrient agar based test media over a specified period of time. Many samplers are subject to effects of temperature sampling duration wind speed and air concentrations.

However current active air sampling technology can be more advantageous and effective in assessing airborne viable contamination in cleanrooms than settle plate monitoring. Airborne gases and vapours are collected by a physical process such as diffusion through a static air layer or permeation through a membrane. Given that both methods are designed to assess viable airborne contamination in cleanrooms there may be no advantage in performing these two parallel methods for the. The airborne contaminants are measured and compared against the volume of air and the results are stated as a concentration usually as milligrams per cubic meter mg m 3 or parts per million ppm.

Air particulate sampling or air monitoring is essential for quality control qc purposes especially in companies that manufacture pharmaceutical products in controlled areas or clean rooms with filtered air. Further it is a challenge to measure non volatile species by passive sampler due to the low diffusion of particle to the adsorption medium. Passive sampling however does not require active air movement from a pump. The collected culture can then be incubated and analyzed ie count bacterial and or fungal colony forming units cfu and identify if required.

Also a long sampling time is often required in order to get enough mass for detection. Active sampling involves the use of an air sampling pump to actively pull air through a collection device such as a filter. There are two main types of air sampling that can be conducted to estimate the level of workers exposure to a certain contaminant stationary or area monitoring and personal chemical exposure monitoring. Well what pharmacists health care practitioners and microbiologists refer to as air sampling can simply be defined as taking a correct measurement of the practical airborne bacteria mold yeast spores and fungal cells which can be collectively referred to as bioburden in the.

It is important to distinguish passive sampling from active sampling which has the same underlying principle but employs moving parts such as pumps to force the sampling medium onto a collecting medium. Any micro organisms contained in the sampled air are retained on the gelatin filter. Active air sampling sites should be done at the same locations or as close as practical to avoid compro mising the other measure or the product integrity. This leaves determination of the number ofsites for passive air sampling and surface sampling.