Abstract
Data from the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) indicate significant changes have occurred in precipitation chemistry and the chemical climate in the United States (US). A Seasonal Kendall Trend (SKT) analysis shows statistically significant increases in precipitation ammonium concentrations at 64% of 159 continental US NADP/NTN sites evaluated from Winter 1985 to Fall 2004 (Dec. 1984-Nov. 2004). Sulfate decreases were widespread, with an SKT analysis indicating statistically significant decreases at 89% of sites evaluated. Ratios of chemical equivalent concentrations of ammonium to sulfate in precipitation have risen to the extent that ammonium now exceeds sulfate over more than half of the continental U.S. on a precipitation-weightedmean annual basis. These trends in the concentrations of ammonium, sulfate, and other species have been accompanied by significant decreases in the frequency of acidic precipitation (pH<5.0) in the last decade.
Original language | English (US) |
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Title of host publication | Acid Rain - Deposition to Recovery |
Publisher | Springer |
Pages | 59-66 |
Number of pages | 8 |
ISBN (Print) | 9781402058844 |
DOIs | |
State | Published - 2007 |
Keywords
- chemical climate
- precipitation chemistry
- trend analysis
ASJC Scopus subject areas
- General Environmental Science
- General Earth and Planetary Sciences