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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