1. Sulfur and Nitrogen Emission Trends for the U.S. By: Brian Ponczak January 31, 2002 Sustainable Air Quality

2. Background Sulfur and Nitrogen are the two key components of fossil fuels. These substances may be harmful or beneficial to our environment depending their quantity, rate of distribution, and chemical form.

3. Sources of Fuel in the U.S. 1850-1880: Wood 1880-1960s: Coal 1940-present: Oil and gas

4. Sulfur Production Western coal has a lower concentration of sulfur than does Midwestern and eastern coal. The Appalachian and Midwestern regions contribute to the majority of sulfur mobilization in the U.S. Since 1960 there has been a reduction in the total sulfur emitted from crude oil. Sulfur emissions from metal smelting are approximately.5-1.5 million tons/year.

5. NOx Emissions NOx emissions are spread evenly over three main sources: transportation, power plants, and industrial sources. NOx emissions are weighted by an emission factor that equals the quantity of nitrogen oxide emitted per unit fuel consumed.

6. Summary In our generation the primary source of sulfur oxides is coal combustion in power plants. Internal combustion engines are the primary source of nitrogen oxides. Sulfur emissions arise from the sulfur concentrations in fossil fuels and metal ores. Nitrogen oxides are primarily formed by chemical reaction of atmospheric nitrogen.

7. What I have learned? Sulfur and nitrogen oxide emissions are formed by separate mechanisms. The recovery and recycling of sulfur from fossil fuels and metal smelting is increasing, but is still insignificant in coal. Sulfur emissions data has changed recently due to the increased average stack height of columns and the relocation of many power plants to rural areas.