The Deeper Impact of Poor Air Quality in the Smokies

One can easily understand how air pollution could affect visibility throughout Great Smoky Mountains National Park. 

What’s not as easy to see, but is just as devastating, is how the concentrations of nitrogen and sulfur in the air are impacting water chemistry, aquatic life and even vegetation. 

The National Park Service reports that Great Smoky Mountains National Park receives the highest level of acid deposition of any monitored national park. In fact, a study of the park’s forest ecosystems found that the combined effects of the nitrogen and sulfur that are being deposited in the soil is greater than what is called the critical load. This is the point at which lower amounts wouldn’t cause problems, while higher amounts could harms plants and upset the balance of minerals in the soil. 

As you might expect, the National Park Service says ecosystems at higher elevations are more vulnerable to acid deposition because of rain, fog and clouds than lower levels. That’s because those areas more exposed. But it’s also because those areas tend to have shallower soils and shorter growing seasons, which means there is little chance for these areas to recover. 

Here are the problems:

  • Acid rain is 5-10 times more acidic that normal rain. 
  • Acidic clouds and fog harm old growth forests. 
  • Acidification of forest soils promotes loss of plant nutrients and release of toxins that hurt vegetation and stream life.
  • Acidification of mountain streams contributes to a loss of diversity of aquatic stream life. 


Bottom line—the Great Smoky Mountains National Park has amazing diversity of life with almost 20,000 species identified living in the park. In addition, new species are still being discovered. But all of that is threatened unless the air is cleaned up.


—Frank Graff

Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!



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