In North Texas, where 10 counties remain non-compliant with Environmental Protection Agency ozone limits, Wednesday’s announcement of a major settlement with an air-polluting cement company was welcome news.Ash Grove Cement Co., in its settlement with the EPA and Department of Justice, has resolved its alleged violations of the Clean Air Act by agreeing to a $2.5 million penalty and promising to invest $30 million in pollution-control technology at its Portland cement manufacturing plants in nine states.At its Texas facility in Midlothian, upwind of the Dallas-Fort Worth area, the company will shut down two older, inefficient kilns, while a third will be replaced with a cleaner, newly reconstructed kiln, the EPA said in a news release.The new kiln, which is expected to be operational in about a year, will produce about the same amount of product but with a 60 percent reduction of nitrogen oxide (NOx), 97 percent less sulfur dioxide (SO2) and 90 percent less particulate-matter emissions, a company spokeswoman told Star-Telegram reporter Jim Fuquay.Overall, the EPA said the settlement will reduce more than 17,000 tons of NOx (a precursor to ozone) and SO2 pollution each year in the nine states where the plants are located. As of 2011, Ash Grove was the largest emitter of NOx in North Texas. The company also will replace old diesel truck engines at its facilities in Texas, Kansas and Arkansas — a $750,000 project — which will lessen smog-forming nitrogen oxides by about 27 tons per year.Some area environmentalists, who have been fighting for lower emissions at kilns in Midlothian for about 20 years, are not satisfied that the settlement goes far enough. They want to see even more pollution control imposed on the cement companies. But reaching a mutual understanding, with positive plans for the future, is what this settlement is all about.The EPA, a much-maligned agency in Texas because of its rules and enforcement, deserves credit for this latest action, which will help protect public health and the environment. The settlement is subject to a 30-day public comment period and final court approval.