Air Sampling involves drawing a known volume of air through a filter, trapping the contaminants and measuring the amount of contaminant captured.
The results are usually expressed as a concentration, calculated by dividing the volume of air by the amount of contaminant captured. To calculate the volume of air, you multiply the flow rate (usually expressed in Litres Per Minute) by the duration of the sample. For this reason, the air sampler must be carefully calibrated before use to ensure the flow rate is correct. Often, multiple samples are required to provide a better understanding of the environment.
There are many different devices which can be used for air sampling:
- Static Area samplers generally have high flow rates, meaning large volumes of air can be sampled in a short space of time. These are useful for pinpointing the source of contamination and for assessing the effectiveness of control measures.
- Personal Air Samplers are smaller in size and have a lower flow rate. They are attached to the operator, and a sample is taken during normal working activity (usually over an 8-hour period). The sampling head is located in the worker’s breathing zone to measure how much particulate matter is inhaled.
In some industries these instruments are a legal requirement to detect the concentration of harmful airborne substances in a worker’s breathing area. These include aerosols, dusts, fumes, smokes and mists. All are a danger to health, as small particles can settle on the lining of the lungs and cause respiratory problems.
By taking air samples, employers can protect their workforce from exposure to airborne contaminants.