Nitrogen oxides (NOx) emissions are emitted primarily from transportation sources, utilities, and other industrial sources and contribute to a variety of environmental problems: the formation of acid rain and acidification of aquatic systems, ground level ozone (smog), and visibility degradation. For these reasons, NOx emissions are controlled in many ways by different levels of government throughout the country.

Mobile sources (tranportation) also contribute significantly to NOx emissions. Overall, over 20 million tons of SO2 and NOx are emitted into the atmosphere each year.

SO2

Sulfur dioxide emissions lead to the formation of sulfate particles in the atmosphere. Sulfate particles account for more than 50 percent of the visibility reduction

                 Air Pollution Page