OHST Practice Exam

Grab samples are used for?

1. 8 hour average

2. Never used

3. To identify peak or ceiling concentration

4. To calculate a TWA for the work shift

The correct answer is: To identify peak or ceiling concentration

Grab samples are specifically used to identify the peak or ceiling concentration of contaminants or chemicals present in the environment at a specific point in time. This kind of sampling is a snapshot that captures a momentary concentration level, which can be vital for assessing exposure risks. For example, in occupational health and safety settings, grab samples can provide immediate data on hazardous substances, helping ensure that exposure limits are not being exceeded at specific times. In contrast, other sampling methods, like continuous monitoring or average sampling, might focus on long-term exposure over an entire work shift, rather than on capturing those critical maximum concentrations. Therefore, grab sampling is particularly valuable for understanding extremes in concentration levels that could pose an immediate risk to worker health and for compliance with regulatory standards concerning peak exposure levels.