Mammoth Cave National Park Air Quality Information
Overview
Mammoth Cave NP is in an industrialized part of the United States. Recently, a number of new power plants have been proposed in Kentucky and Tennessee, and the emissions from those sources are likely to affect air quality at the park.
A National Atmospheric Deposition Program/National Trends Network (NADP/NTN) wet deposition monitor has been operating at Mackville, Kentucky, 100 km northeast of the park, since 1983 (site #KY03). The state of Kentucky has monitored precipitation amount and chemistry at Mammoth Cave NP since 1992. A comparison of state and NADP/NTN data indicates the Mackville site likely underestimates pollutant deposition at Mammoth Cave NP. A NADP/NTN monitor, along with a Mercury Deposition Network monitor, will be installed at the park this year.
A Clean Air Status and Trends Network (CASTNet) dry deposition site has been operating at Mackville since 1990 (site #MCK131). Site data indicate a decrease in dry sulfur deposition, but no trend in dry nitrogen deposition. CASTNet estimates total nitrogen deposition at the site is composed of 38 percent dry deposition and 62 percent wet deposition, while total sulfur deposition is 50 percent dry and 50 percent wet. A CASTNet monitor will be installed at Mammoth Cave NP this year.
Limited soil studies indicate some soils in the park are sensitive to acidification from atmospheric deposition. Surface water chemistry data collected in the Green and Nolin Rivers show that the rivers are well buffered against acidification. The surface water chemistry of small creeks in the park has not been systematically monitored. There is concern that during rainstorms, when there is little opportunity for rainwater to come into contact with deep soils, episodic acidification could occur.
Ozone has been monitored at Mammoth Cave NP since 1985 (site #210610500 from 1985 to July 1997 and site #210610501 from August 1997 to present). The data indicate exceedances of the 1-hr human health-based primary National Ambient Air Quality Standard (NAAQS) in 1987, 1988, and 1999, and many calculated exceedances of the new 8-hr primary NAAQS.
Ozone injury surveys were conducted in the park in the 1980s and foliar injury was observed on a number of species of plants. Such surveys have not been conducted in recent years; however, studies are planned in the near future. Ozone concentrations in Mammoth Cave NP consistently exceed levels known to cause foliar injury and growth loss in sensitive species of vegetation.
As part of the Interagency Monitoring of Protected Visual Environments (IMPROVE) network, visual air quality in Mammoth Cave NP has been monitored using an aerosol sampler (1991 through the present), nephelometer (1993 through the present), and 35mm camera (1992 through 1997). The U.S. Environmental Protection Agency’s new Regional Haze regulations require improving visibility in Class I air quality areas on both the best visibility and the worst visibility days. A review of aerosol data collected at Mammoth Cave NP shows no significant trend in visibility on good, bad, or average visibility days since 1991.
This summer, a Western Kentucky University professor will begin investigating the fate and transport of mercury in the karst aquifer system of Mammoth Cave NP. The researcher hopes to 1) establish the extent, occurrence, and distribution of mercury in groundwater, surface water, and sediments in the park; 2) determine the level of mercury in fish and mussels in the park; and 3) investigate the fate and transport characteristics of mercury in a karst aquifer. This study, combined with mercury deposition monitoring, will give the National Park Service a better understanding of how mercury emissions from power plants and other sources are affecting resources at Mammoth Cave NP.
Additional information on in-park emissions at Mammoth Cave NP is available in 2000 Air Emission Inventory- Mammoth Cave National Park (November 2002).