A couple of years ago, three environmental groups and more than a dozen states filed petitions for review to challenge EPA`s 2006 revision of the National Ambient Air Quality Standards (NNAQS) for particulate matter. In particular, the groups challenged EPA`s decision not to tighten the nearly decade-old annual standard for fine particulate matter (which includes soot). Last month, a federal appeals court threw EPA `s soot limits into doubt in American Farm Bureau Federation v. EPA (PDF:187KB), when it ruled that the agency failed to adequately explain why the fine particulate matter standard was sufficient to protect public health. The court remanded the fine particulate matter standard to EPA for reconsideration. During the remand, the rule will remain in effect. With respect to an industry challenge to EPA`s regulation of coarse particulate matter, the court held that EPA need not wait for conclusive evidence of adverse health effects before regulating. It rejected the challenge and upheld that portion of EPA`s regulation. While many are claiming that the ruling corrects an injustice and that tougher air standards will save lives, the Farm Bureau (PDF:187KB) is concerned that ranchers and farmers may face additional and unwarranted regulations.