What method uses a filter placed at a fixed location in the work area at the workers' breathing zone?

The method that employs a filter placed at a fixed location in the work area at the workers' breathing zone is area sampling. This sampling technique is intended to measure the concentration of airborne contaminants in a specific location, allowing for an assessment of the exposure levels within the environment where workers might be exposed to hazardous materials, such as asbestos.

Area sampling is particularly useful to identify potential contamination levels in a work area and can highlight the effectiveness of engineering controls or respiratory protective equipment. By capturing air at a fixed point, it provides a snapshot that reflects the atmospheric conditions that workers are likely to encounter in that particular zone.

In contrast, other sampling methods focus on different aspects: personal sampling involves measuring contaminants directly at the worker’s breathing zone by attaching a filter or sampling device to the worker, while point sampling is typically associated with specific, localized measurements. Static sampling focuses on measuring the levels of airborne contaminants in environments where there is no active work being done, which may not fully represent the exposure risks for active workers.