Master's Thesis Abstract by Sarah Brace (1996)

Few data exist on ozone exposure in rural and wildland areas of western Washington, USA. We measured tropospheric ozone in Mount Rainier National Park and the Puget Sound region, Washington, using electronic analyzers and passive samplers during the summers of 1994 and 1995. Electronic analyzers recorded hourly ozone concentrations from five locations between Seattle and Mount Rainier. Ozone concentrations increased with distance from Seattle with maximum hourly levels recorded at Enumclaw (310 m elevation, 50 km SE of Seattle). Paradise (1650 m elevation, 100 km SE of Seattle) had the highest monthly mean concentration of all sites measured with analyzers (35 ppbv). Diurnal patterns on high ozone days indicate that concentrations at Paradise remained close to 60 ppbv during the early morning and nighttime hours, whereas ozone concentrations closer to Seattle had higher peaks during the afternoon but dropped to near zero at night. Passive ozone samplers measured weekly average ozone exposures in four river drainages within Mount Rainier National Park, across an elevation gradient ranging from 450 m to 2100 m. In all drainages, ozone levels increased with elevation, with highest average weekly ozone exposure (47 ppbv) recorded at 2100 m. The Carbon River drainage in the northwest and Nisqually River drainage in the southwest had slightly higher average ozone exposure than the White River drainage in the northeast portion of the Park. These data provide an important reference point for air quality in western Washington, where projected increases in population and fossil fuel combustion are expected to result in increased ambient ozone exposure.