Title: Temporal variability and case study of high O₃ episodes in two southeastern US national parks

Authors: Daniel Q. Tong, Viney P. Aneja, S. Pal Arya, John D. Ray

Addresses: Program in Science, Technology, and Environmental Policy (STEP), Woodrow Wilson School of International and Public Affairs, Princeton University, Princeton, NJ 08544, USA. ' Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695–8208, USA. ' Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695–8208, USA. ' Air Resource Division, National Park Service, 12795 W. Alameda Parkway, Denver, CO 80225–0287, USA

Abstract: Despite a decreasing trend nationwide, eight-hour O₃ concentrations in 25 of US national parks have increased by 8% during last decade. This study presents a 13-year observation of high O₃ at the Great Smoky Mountains (GRSM) and Mammoth Cave (MACA) national parks, both among the 25 impacted parks. Although there is no monotonic increase, the later half witnessed three-fold exceedances than the former. O₃ exceedances occurred most frequently in June at MACA, and in August or September at GRSM. High O₃ episodes at MACA occurred during daytime or early evening, but exceedances at GRSM can be found in any hour. Air masses with high O₃ at GRSM came from all directions, whereas those at MACA are predominantly from the southwest. Case studies show that high O₃ episodes at MACA are developed under clear sky, high temperature, low humidity, and weak winds traveling in a uniform anti-cyclonal pathway.

Keywords: air quality; air pollution; high O₃ episodes; national parks; O₃ exceedance; temporal variability; national parks; United States; USA; ozone concentrations.

DOI: 10.1504/IJGENVI.2006.010159

International Journal of Global Environmental Issues, 2006 Vol.6 No.2/3, pp.173 - 188

Published online: 23 Jun 2006 *

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