What's in the Air.

That brown haze that obscures the crest of the Blue Ridge Mountains further than 50 miles consists of several manmade pollutants, mainly sulfates and organic carbon particles. Sulfates, which comprise at least 80% of the pollution, emanate from coal-burning power plants and industries. Industries also contribute organic carbon particles, as do automobiles and trucks. When sunlight reflects off of the particles in the air, it magnifies them, creating the "haze" that looms over the Blue Ridge. Sulfate particles become larger during humid weather because the moisture in the air "sticks" to the particles, so the haze is more opaque on hot, humid days.

Sulfur dioxide, which creates sulfates, is a colorless, reactive gas produced during the burning of sulfur-containing fuels created during metal smelting or other processes.

In the 1950s, a person with good vision could see mountains up to 140 miles away. Now that range is only 35-90 miles because of the pollution haze. Sulfates and the other pollutants also leave acid deposits in the trout fisheries and on the soil, also known as "acid rain." On the peak of Mount Mitchell, for example, the naked Frazer fir trees mark the graveyard of these once majestic evergreens, stripped by years of acid rain.

Children and adults with asthma experience the most serious effects from sulfates and organic carbon particles. Even after relatively brief exposure, they typically suffer from chest tightness, difficulty breathing, and wheezing. When sulfate levels are particularly high, people who do not have asthma may exhibit these symptoms as well, which may account for the increase in emergency room visits by children with asthma (watch Air Pollution Part 3).

Sources:
US Environmental Protection Agency
NC Dept. of Environment and Natural Resources
North Carolina Division of Air Quality