Purchasing and using equipment for air monitoring can be a confusing process for someone who is new. In this blog post we discuss about which top factors you should keep in mind before using an air sampler.

Air sampling and monitoring indoors and other controlled environments require samples of large volumes of air. This could range to at least 1 m3. One also needs to ensure that these samples are representative and the results of the air samples collected are accurate enough.

Air samples collected should meet the regulatory OSHA standards, or guidelines. To ensure this, it is essential that air samplers are properly validated and regularly calibrated. This ensures accuracy of results.

There are a number of factors to consider when deciding which air sampler to choose

The physical efficiency of the sampler: The relative efficiency of the air sampler in collecting particles over a range of sizes should be accurate.
The biological efficiency of the air sampler: Like for the physical efficiency, the biological efficiency, in collection of microorganisms on a surface or in a liquid should also be viable.
Validation: The instrument should be validated for its intended application and environment.
Flow rate of the air sampler: With large sample sizes, the flow rate of air through the sampling head is critical to the accuracy of the result. Be sure to select an air sampler that can accurately process large sample sizes.

ISO 14698-1 standard lists the methods for estimating the physical and biological efficiencies of air samplers. Air sampler manufacturers typically employ a third party laboratory to help validate their instruments. This is done by challenging the instrument with particles and microorganisms in a controlled environment.

The physical efficiency of air samplers should be tested against membrane filtration sampling before using. The biological efficiency on the other hand can be compared with an established reference air sampler. Validating for specific applications should be done using a new sampling method in parallel with the existing system. This should be done for a period that is sufficient enough to provide a valid comparison.

Flow rate of the air sampling fan or pump should always be calibrated properly. One should always validate it against a certified flow meter – preferably by a third party.  This should be done at least once every twelve months. Regularly calibration by the user ensures that the air sampler has not developed a fault or suffered any adverse damage.

Air sampler suppliers can provide the user validation methods and recommendations for their instruments. These can be used by a novice to judge which instrument to purchase and also ensures the correct use. They also offer a validation service and equipment which is typically an anemometer. This helps to calibrate samplers on site. So, be sure to use them before putting the air sampler to work!