Still, the area has made great strides in recent years. Overall, harmful emissions are down 80% over the past 20 years, according to Sadredin.
Future improvement should come from recent Environmental Protection Agency programs that offer cash incentives to replace dirty diesel engines in trucks, tractors and buses. Jared Blumenfeld, the EPA's regional administrator, said local farmers have replaced many of their old tractors, as well as diesel-fueled water pumps with electrical ones.
Source: American Lung Association's State of the Air 2013 report 1. Ranking is based on year-round particle pollution. This is in the air we breathe and consists of such things as dust, metals, smoke, exhaust, pollen and acids, like nitrates and sulfates. 2. The data for cardiovascular disease includes all cases in a given city whether they were caused by air pollution or not. Air pollution puts those with cardiovascular disease at a higher risk of health issues. 3. Ozone is created when a chemical or fossil fuel, like coal or gasoline, is partially burned and the unburned hydrocarbons, when combined with ultraviolet light, form a gas that is very corrosive to lungs.
By Les Christie@CNNMoney - Last updated April 24 2013 12:33 PM ET