Dominion’s coal-fired power plant under construction in Wise County Virginia will add to southwest Virginia’s air pollution. But Appalachian Power’s existing generating station in nearby Russell County will reduce some of its emissions. The process for approving air permits for the $1.8 billion Dominion Virginia Power plant resulted in a discovery that Appalachian’s Clinch River plant could exceed its permitted sulfur dioxide emissions. Company spokesman John Shepelwich says the utility will reduce its emissions of sulfur dioxide by about one-third under a consent order between the utility and the state Department of Environmental Quality. The plant has a current limit of 28,000 tons of sulfur dioxide each year, but the consent order issued last month will cut the maximum to about 19,000 tons. Dominion’s 585-megawatt plant will be allowed to emit just over 600 tons of sulfur dioxide a year, meaning a net decrease in emissions of that pollutant allowed in the region.