Assessment of atmospheric exposure and deposition to high-elevation forests in the eastern United States

摘要: The report summarizes the results of four year field measurement and data analysis program MCCP. MCCP is sponsored by U.S. Environmental Protection Agency as part joint Forest Service-EPA Spruce-Fir Research Cooperative. objectives project have been met result an assessment principal atmospheric constituents they impact high elevation forests Eastern Deposition SO4(-2), NO3(-), H(+), NH(4+) in cloud water represents a significant input to forest canopies with elevations greater than 1000m. Cloud deposition can exceed wet (rain) may be dominant process for sulfate nitrate compounds during growing season frequently exposed clouds. pH concentrations much 0.6pH units lower rain. SO(4+) NO3(-) are also higher precipitation. Ozone reveals that differences exist between ozone at low sites. primary effect difference produce mean longer episodes