Which of the following conditions allows for a Dust Control Coordinator exemption?

• A. All areas disturbed are over 5 acres
• B. The disturbed area has been previously stabilized
• C. No disturbances have occurred in the last year
• D. The area is regularly irrigated

Answer: (B)

The correct answer is rooted in the understanding of how stabilization affects dust control regulations. When an area that has been disturbed is stabilized, it typically means that measures have been taken to minimize the potential for dust generation. Stabilization could include the application of vegetation, mulch, or other materials that effectively cover the soil and reduce the amount of fine particles that can become airborne.

In the context of dust control, a previously stabilized area is less likely to produce significant dust emissions upon further disturbance. As such, this condition often qualifies for exemptions from dust control requirements that would otherwise apply to new or untreated disturbed areas. The rationale behind this exemption is to facilitate operations in areas where the risk of air pollution has already been mitigated through effective dust control practices.

This understanding reinforces why other circumstances do not qualify for the exemption as effectively. For example, simply having disturbed areas larger than a certain size does not inherently minimize dust emissions. Similarly, a lack of disturbances or regular irrigation may not provide the same assurance against dust generation as effective stabilization does. Thus, the previously stabilized condition presents a compelling case for exemption within dust-generating operations.