Jefferson County got a failing grade for smog pollution because it had an average of 10 days each year over a three-year period that received an “orange” rating for ozone. That means that between 2008 and 2010, there were about 10 days each year when the air was deemed unhealthy for sensitive groups: seniors, young children, those with asthma and people with other heart and lung ailments.

There were no days that were deemed generally unhealthy for the rest of the population. Ten “orange” days or more is the threshold for receiving a grade of F. Oswego County had two ozone “orange” days and received a B grade for smog pollution. St. Lawrence and Lewis counties don't collect adequate data to grade their air quality.

Ed Miller is vice president for public policy with the American Lung Association of the Northeast. He says air pollution doesn't stop at state boundaries, "You're getting the byproduct of the midwest power plants, where their emissions travel hundreds or even thousands of miles away and end up causing problems downwind from where those sources of pollution are. It's not atypical to see that kind of thing; in fact, some people might be familiar with the Acadia National Park in Bar Harbor, Maine. Sometimes on Cadillac Mountain there, they have higher ozones than New York City."

A state official responsible for the air quality monitoring systems says Canadian industrial sources as well as coal-fired power plants in the midwestern U.S. are the likely sources of Jefferson County's ozone. And weather patterns probably explain the disparity between Jefferson and Oswego counties' air quality grades.

Ozone is created when the byproducts of combustion are mixed with heat and sunlight. That's why it's a good idea to exercise outdoors in the mornings during the ozone season, which is mid-spring through early fall, rather than in the hotter afternoons. Sensitive groups should stay in air-conditioned spaces indoors during high-ozone days.

Miller says new science looking at the health effects of smog suggests that the existing grading standards are actually too relaxed. The Lung Association wants to see tighter legal standards for air quality throughout the country, although some business interests would likely oppose that.