According to an American Lung Association’s “State of the Air 2015” report released Wednesday, Orange County had the cleanest air among Hudson Valley counties. The study took and measured data from the years 2011 to 2013 to compile the rankings.

The Daily Freeman says that report gave Orange County a B grade for the number of high ozone days, compared to a C in the last report, which covered the years 2010 to 2012. Dutchess County received a C for high ozone days compared to a D during the previous study. Putnam County improved from a D to a B. Rockland County, however, fell from a C to a D. Westchester bottomed out at an F, which is due to it's closer proximity to New York City .Ulster County received an Incomplete. The reason the incomplete grade was not explained in the ALA's report.

The American Lung Association says that a county needs three years of data for the association to adequately compare levels of pollution with the national standards.