CONCORD, N.H. – For the first time in nearly two decades, New Hampshire is earning passing grades from the American Lung Association for three common types of air pollution.

The organization issued its 18th annual State of the Air report Wednesday based on data collected by government agencies in 2013 and 2015. Improving scores in Rockingham and Hillsborough counties boosted the state’s overall picture, though the report downgraded Coos County from a C to a D.

The report found continued improvement in air quality across the country. But officials note that 40 percent of Americans live with unhealthful levels of either ozone pollution – commonly known as smog – or particle pollution, also known as soot.