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.
Active air sampling definition.
Active sampling requires the use of a pumping device to actively pass air through an air sample container whereas passive sampling does not.
Passive sampling however does not require active air movement from a pump.
Active sampling involves the use of an air sampling pump to actively pull air through a collection device such as a filter.
Airborne gases and vapours are collected by a physical process such as diffusion through a static air layer or permeation through a membrane.
Air sampling is the process of capturing contaminants in a known volume of air.
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.
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.
The collected culture can then be incubated and analyzed ie count bacterial and or fungal colony forming units cfu and identify if required.
Passive air sampling passive air sampling i e settle plates is a frequently.
Many samplers are subject to effects of temperature sampling duration wind speed and air concentrations.
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.
Any micro organisms contained in the sampled air are retained on the gelatin filter.
Passive sampling relies on the kinetic energy of gas molecules and diffusion of the gases in an enclosed space onto a sorbent medium.
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.
However current active air sampling technology can be more advantageous and effective in assessing airborne viable contamination in cleanrooms than settle plate monitoring.
This leaves determination of the number ofsites for passive air sampling and surface sampling.
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.
Further it is a challenge to measure non volatile species by passive sampler due to the low diffusion of particle to the adsorption medium.
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.
Also a long sampling time is often required in order to get enough mass for detection.
