On a brighter side the USA has toughened the standards recently.. WASHINGTON (Reuters) - In a big win for environmentalists, a US appeals court on Tuesday rejected an attempt by business groups to overturn federal clean-air standards that would clamp down on pollution. The decision would allow the Environmental Protection Agency (news - web sites) to protect the public health by limiting pollution levels across the country for smog and fine, sooty particles--although other legal issues remain to be resolved. A coalition of business groups, led by the American Trucking Associations, filed a lawsuit seeking to overturn the EPA's 1997 pollution standards that would require ozone concentration levels not to exceed an average 0.08 part per million (PPM) during an eight-hour period and limit soot particles to 65 micrograms per 24-hour period. The agency decided not to implement the clean air standards until the main legal disputes were settled by the courts. The agency estimated the tough pollution standards would prevent 15,000 premature deaths, 350,000 cases of asthma and 1 million cases of decreased lung function in children. However, business groups claimed that the standards were arbitrary and had no scientific basis. The US Court of Appeals for the District of Columbia Circuit rejected that argument, saying EPA "has no obligation either to identify an accurate 'safe level' of a pollutant or to quantify precisely the pollutant's risks." The court added that "EPA must err on the side of caution" and set pollution standards at "whatever level it deems necessary and sufficient to protect the public health with an adequate margin of safety, taking into account both the available evidence and the inevitable scientific uncertainties." Environmental groups welcomed the court's decision and called on the EPA to immediately begin determining which parts of the country were not complying with the pollution standards. "For nearly five years, the legal wrangling by industry lawyers has delayed critical progress in delivering cleaner, healthier air to the millions of Americans that will be protected by these standards," said Vickie Patton, senior attorney for Environmental Defense. Three states--Ohio, Michigan and West Virginia--joined the industry in fighting the tough pollution rules. EPA must still resolve two issues surrounding the pollution standards. First, the Supreme Court has ordered the agency to reexamine its plan for implementing the standards. Second, the circuit court for the District of Columbia ordered the EPA to consider industry claims that smog is beneficial for human health because it screens out ultraviolet rays.