Which of the following are the two types of personal samples used in asbestos monitoring?

The correct answer is based on the understanding of air sampling protocols used in occupational health, particularly in the context of asbestos exposure. STEL (Short-Term Exposure Limit) and TWA (Time-Weighted Average) are both critical measures used to monitor and evaluate the exposure levels of workers to hazardous substances such as asbestos.

STEL refers to the maximum allowable concentration of asbestos in the air that a worker can be exposed to over a short period, typically 15 minutes, without experiencing harmful effects. It is designed to protect workers from acute effects associated with short-term exposure spikes.

TWA, on the other hand, calculates the average exposure over a longer period, usually an 8-hour workday. The TWA helps ensure that workers’ exposure levels are kept within safe limits over the duration of their typical work schedule, taking into account variations in exposure that may occur throughout the day.

Both of these measurements are crucial in asbestos monitoring because they provide comprehensive information about potential health risks associated with different durations of exposure. Properly using both STEL and TWA helps in assessing whether current safety measures, personal protective equipment, and workplace practices are adequate in protecting workers from the toxic effects of asbestos.

In contrast, the other options do not present the correct combination