"Air quality in many of our national parks has worsened significantly over the years," said Earthjustice attorney David Baron, who is representing Environmental Defense in the lawsuit that was argued today in the United States Court of Appeals for the District of Columbia Circuit (Case No. 05-1446). "We contend that EPA's notion that current standards are sufficient to protect air quality is indefensible."

The National Parks Service air monitoring data shows that air quality in our many of our national parks has been worsening steadily. In 1990, a federal court of appeals instructed EPA to go back to the drawing board to ensure its rules meet the Clean Air Act's mandate to protect and enhance air quality in national parks, wilderness areas, national monuments, and other natural areas. But after 15 years of delay in responding to the court's order, in 2005 EPA merely readopted the same program that has already been proven to be inadequate, the groups contend.

"The purpose of the Clean Air Act is to protect human health and the environment, but this new rule fails to do either," said Vickie Patton, an attorney with Environmental Defense. "Nitrogen emissions damage lungs and increase the risk of asthma attacks, lung disease and premature deaths. They also combine with other airborne substances to impair visibility and form acid rain, which damages national parks and other pristine areas."

NOx pollution also damages ecosystems in parks, wilderness, and coastal areas. In August 2005, for example, 41% of the Chesapeake Bay had too little oxygen to support a healthy ecosystem, due in part to nitrogen deposited into the Bay from air pollution. Deposition of reactive nitrogen is also damaging alpine ecosystems in the Rockies and Cascades, threatening them with loss of native fish and plant species.