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Enhanced Air Quality Monitoring


Big Meadows Monitoring Site
Shenandoah NP, VA
There are three enhanced monitoring stations operated by the NPS at Shenandoah, Great Smoky Mountains and Mammoth Cave National Parks. Two additional stations operated by the states and part of the EPA PAMS network are located at Acadia NP and Cape Cod NLS. These stations are designed to better understand photochemical oxidant pollution by measuring the precursors to ozone and a select number of tracer pollutants. The participation of university researchers is a key part of these research projects.


US Map
The map shows NPS monitoring locations in relation to the domains of several regional ozone research studies. The four eastern parks, Acadia, Shenandoah, Great Smoky Mountains, and Mammoth Cave, have enhanced instrumentation to participate in the regional studies.

For more information on the regional ozone studies, consult the web pages below:


Research grade instrumentation to measure 1 to 5-minute average continous concentrations of CO, NO, NOx, NOy, and SO2 plus cannister samples for VOC were added to enhanced stations.

photograph of Shenandoah National Park, VA
Shenandoah National Park


photograph of Great Smoky Mountains National Park, TN
Great Smoky Mountains National Park


photograph of Mammoth Cave NP, KY
Mammoth Cave National Park



The hourly ozone and meteorological data is available from the EPA AIRS database or directly from NPS. Ozone precursor data is available to cooperating researchers, air pollution modelers, and air quality agencies by request only. Hourly ozone and meteorological data for the three enhanced monitoring stations are available below for 1995 to 1999. The files are zipped to reduce their size. Each file contains yearly ascii data in column format with space delimiters and may be imported easily into Excel or other spreadsheet programs. A header gives site information, column labels, and units.

Park Code 1995 1996 1997 1998 1999*
Great Smoky Mtns GRSM-CC X X X X X
Mammoth Cave MACA-HM X X X X X
Shenandoah SHEN-BM X X X X X

*Only validated data is included for 1999.


A Shenandoah data workshop was held on Dec. 15, 1998 with researchers, industry representatives, Viginia Dept. of Environment Quality staff, and Park Service technical staff to review findings. Several publications are in preparation based on research at Shenandoah National Park. Overview report and summary for participants of the Shenandoah Data Workshop:


Gaseous Pollutant Monitoring, Program Manager - John Ray (NPS-ARD) - (303) 969-2820

Publications and Results

Doddridge, B. G., R. R. Dickerson, J. Z. Holland, J. N. Cooper, R. G. Wardell, and O. Poulida, Observations of tropospheric trace gases and meteorology in rural Virginia using an unattended monitoring system: Hurricane Hugo (1989), a case study, J. Geophys. Res., 96, 9341-9360 (1991).

Poulida, O., R.R. Dickerson, B. G. Doddridge, J. Z. Holland, R. G. Wardell, and J. G. Watkins, Trace gas concentrations and meteorology in rural Virginia: 1. Ozone and carbon monoxide, J. Geophys. Res., 96, 22,461-22,475 (1991).

Doddridge, B. G., R. R. Dickerson, R. G. Wardell, K. L. Civerolo, and L. J. Nunnermacker, Trace gas concentrations and meteorology in rural Virginia: 2. Reactive nitrogen compounds, J. Geophys. Res., 97, 20,631-20,646 (1992).

Olszyna, K. J., E. M. Bailey, R. Simonaitis, J. F. Meagher, O3 and NOy relationships at a rural site, J. Geophys. Res., 99, 14,557-14,563 (1994).

Jacob, D. J., L. W. Horowitz, J. W. Munger, B. G. Heikes, R. R. Dickerson, R. S. Artz, and W. C. Keene, Seasonal transition from NOx- to hydrocarbon-limited conditions for ozone production over the eastern United States in September, J. Geophys. Res., 100, 9315-9324 (1995).

Ray, John D., Ron L. Heavner, Miguel Flores, and Clifton W. Michaelsen, Surface-level measurements of ozone and precursors at coastal and offshore locations in the Gulf of Maine, J. Geophys. Res., 101, 29,005-29,011 (1996) Reprint (pdf 2.5 mb).

Cooper, Owen Roger, An ozone climatology study for Big Meadows, Shenandoah National Park, Virginia: 1989-1994, Master of Science Thesis, Dept. of Environmental Sciences, University of Virginia, Charlottesville, VA, 1997.

Ryan, W.F., B.G. Doddridge, R.R. Dickerson, R. M. Morales, K. A. Hallock, P. T. Roberts, D. L. Blumenthal, J. A. Anderson, and K. L. Civerolo, Pollutant transport during a regional O3 episode in the mid-Atlantic states, J. Air & Waste Manage. Assoc., 48, 786-797 (1998).

Hallock-Waters, Kristen A., B. G. Doddridge, R.R. Dickerson, Shane Spitzer, and John D. Ray, Carbon monoxide in the US mid-Atlantic troposphere: Evidence for a decreasing trend, Geophys. Res. Letters, 26, 2861-2864 (1999).

Cooper, O.R., and J.L. Moody, Meteorolgical controls on ozone at an elevated eastern United States regional background monitoring site, J. Geophys. Res., 105, 6855-6869 (2000).

Stehr, J. W., R.R. Dickerson, K. A. Hallock-Waters, B. G. Doddridge, and D. Kirk, Observations of Noy, CO, and SO2 and the origin of reactive nitrogen in the eastern United States, J. Geophys. Res., 105, 3553-3563 (2000).

Hallock-Waters, Kristen A., Observations of CO, O3, and SO2 over the US mid-Atlantic, Masters thesis, University of Maryland (2000).

Hallock-Waters, K.A. (2000) Trace gas observations over rural Virginia: Photochemistry and transport, Ph.D. dissertation, Dept. of Chemistry, University of Maryland, College Park, MD.

Spinnenweber, M. M. (2001), Trace Gases in Shenandoah National Park, Virginia: Use of the Big Meadows Site as a Regional Ozone Forecast Tool, Master's thesis, Department of Meteorology, University of Maryland, College Park, MD.

Cooper, O.R., and J.L. Moody, Meteorological controls on ozone at an elevated eastern United States regional background monitoring site, J. Geophys. Res., 105, 6855-6869 (2000).

Kang, D., V. P. Aneja, R. G. Zika, C. Farmer, and J. D. Ray, Non-methane hydrocarbons in the rural southwest United States National Parks, J. Geophys. Res., 106, 3133-3155 (2001).

Kang, Daiwen, (2001), Measurement, Modeling, and Analysis of Nonmethane Hydrocarbons and Ozone in the Southeast United States National Parks, Ph.D. thesis, Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Rayeigh, NC

D. Kang, V.P Aneja, R.Mathur, and J. D. Ray, Non-Methane Hydrocarbons And Ozone In The Rural Southeast United States National Parks: A Model Sensitivity Analysis And Its Comparison With Measurement, J of Geophys Res, 108, D19, 4604,doi10.1029/2002JD003054, 2003.

Tong, D. Q., Kang, D., Aneja, V.P., and Ray, J. D., Reactive nitrogen oxides in the southeast US national parks: source identification, origin, and process budget, Atmos. Environ., 39, 315-327 (2005). Reprint (pdf .9mb).

Kang, D., Aneja, V.P., Mathur, R., and Ray, J. D., Observed and modeled VOC chemistry under high VOC/NOx conditions in the Southeast US national parks, Atmos. Environ., 38, 4969-4974 (2004). Reprint (pdf .4mb).

Cheng, Meng–Dawn and Roger L. Tanner, Characterization of ultrafine and fine particles at a site near the Great Smoky Mountains National Park, Atmos. Environ., 36, 5795–5806 (2002). Reprint (pdf 1.9mb).

updated on 01/17/2007  I   http://nature.nps.gov/air/studies/enhanced.cfm   I  Email: Webmaster