Air Pollution Standard Challenged In Court

EPA's controversial new air quality standard for fine particulate matter—defined as particles with a diameter of 2.5 µm or lessµis under challenge in federal court. Thirteen states, the District of Columbia, and several environmental and health groups are arguing that the standard is too weak to protect public health and the environment. Meanwhile, industry and agriculture groups claim that the standard is too stringent. In September 2006, EPA revised the two-part standard, last modified in 1997 (C&EN, Oct. 2, 2006, page 38). The agency maintained the yearly average concentration for fine particulate matter of 15 µg/m³ of air, disregarding the advice of its science advisers, who recommended lowering this to between 13 and 14 µg/m³. EPA did lower the daily maximum allowable concentration of fine particulates in air to 35 µg/m³ from 65 µg/m³. The groups challenging the standard filed their lawsuits in December 2006.