Frequency of sampling per location. The air sampling professional can only be at one place at one time. A prioritization of air monitoring activities must consider the potential receptors and locations where early detection of changing conditions are important. Now that the sampling grid has been defined, we are ready for conducting the air monitoring. This can not be emphasized enough.
Erroneous measurements lead to erroneous judgments about the hazard zone boundaries.
If the air sampling professional is not familiar with the capabilities and limitations of a particular instrument, they should not use that instrument. Properly functioning instrument. If the air sampling professional does not have confidence in the functioning of the instrument, it should not be used. Analytically, there is no such thing as 0. Equally important here, is to note whether the detection limit is above or below the standards that you will be using to determine the hazard zone boundary.