When taking outside samples for AHERA, how far should the samples be taken from the entrance of the worksite?

When collecting outside samples for the Asbestos Hazard Emergency Response Act (AHERA), the guideline specifies that samples should be taken at least 50 feet from the entrance of the worksite. This distance is significant as it helps to ensure that the samples represent the background or ambient air quality, rather than being influenced by the immediate activities or disturbances that may occur directly at the entrance. Sampling at this distance allows for a more accurate assessment of any potential asbestos contamination in the surrounding environment. Distancing the sampling point from the worksite entrance minimizes the risk of interference from dust or fibers that may be generated by ongoing operations, thus providing a clearer picture of the asbestos levels in the area.