Joshua Fu
While the iconic blue mist of the Smoky Mountains is caused by a natural process of trees expelling water vapor and volatile organic compounds, there is another kind of regional haze produced by human pollution that thickens the sky and causes harm to human health and natural resources such as forests.
John D. Tickle and James G. Gibson Professor Joshua Fu recently spoke to the Knoxville News Sentinel for the subscriber-only article “The Smokies’ namesake haze is part nature, part pollution,” where he discusses the chemical compounds involved in this regional haze.
When nitrous and sulfur oxides from air pollution, or NOx and SOx, meet ammonia emissions, Fu says that it causes a photochemical reaction, producing PM 2.5, a particulate matter that causes haze and can be absorbed through the lungs. Further, when the NOx emissions interact with the natural off-gassing of trees, it produces ozone gas too.
He added that reducing haze and ozone depends on the continuous reduction of both SOx and NOx emissions.
Outside of visibility issues, the article also examines the health implications of this haze. Studies suggest that exposure to this kind of air pollution can be as bad as cigarette smoke.
Fu, who is also a member of the Tennessee Department of Environment and Conservation Air Pollution Control Board, said that industrial and power plants and traffic are the largest sources of regional haze in the surrounding areas and through long-range transport from other states. He emphasizes we need a policy to control ammonia emissions as well as to reduce the production of fine particulate matters, which is not addressed in the current regulations yet.