US environmental regulators approve Arizona's plan to measure fine particulate matter

US environmental regulators have approved parts of Arizona's plan to enforce air quality standards for fine particulate matter. This means Arizona can now move forward with its updated approach to monitoring and controlling air pollution from tiny particles.

The US environmental regulators set national air quality standards, but states must create their own plans to meet them. This approval means Arizona's specific methods for tracking and reducing fine particulate pollution are now officially recognized. It also adds La Paz County to an existing air quality control region, which means it will now be subject to the same air quality rules and monitoring as Mohave and Yuma counties.