AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
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Decrease in Acid Rain Over 25-Year Study at Paradise, Mt.Rainier National Park
ASHLEEN REDDY, Jeff Barnes, Naomi Beebe, Rebecca Lofrgen, Barbara Samora, Anne Johansen, Central Washington University
Abstract Number: 457 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Weekly wet precipitation samples from Paradise in Mt. Rainier National Park, WA, were analyzed for major anions and cations, conductivity and pH. Volume weighted 3-month averages were tested for significant trends throughout the 25-year monitoring period starting in 1989 and compared with analogous data collected at established National Atmospheric Deposition Program (NADP) sites throughout the state. At Paradise, proton concentrations decreased by a significant amount of 59% resulting in a pH increase of wet precipitation from 5.1 to 5.5 (P=0.001). Similar trends were observed for the acidic sulfate and nitrate species. Results compare well with observations made at WA NADP sites. Results indicate that air pollution standards contribute significantly to the decrease in acid rain deposition to this pristine and vulnerable high elevation location, and that trans-Pacific transport of pollution is not detected in the form of acid rain and associated anions.