These animations display the National Trends Network (NTN) concentration and
deposition maps of pH, sulfate, nitrate, and ammonium and deposition maps of H+, sulfate, nitrate, ammonium, and total inorganic nitrogen
from nitrate and ammonium beginning in 1985.
The pdf files will work best if you download the file and open in Adobe Acrobat Reader. The animations may not automatically advance on mobile devices or when opening in an Acrobat Reader browser plug-in. On a PC, as long as the file is allowed to open in full-screen mode, the slides should advance automatically.
After the Powerpoint files opens, putting Powerpoint into Presentation mode (F5) will make the slides automatically advance.
Each frame represents a three-year moving average of annual precipitation-weighted mean concentration or deposition. For example, the 1985 concentration map displays the average of 3 precipitation-weighted mean values (1984,1985,and 1986).
At least three factors are at work changing the spatial patterns from year to year and over the period of record: emissions changes, changes in weather patterns, and chemical changes in the airborne pollutants that are removed by precipitation.
If you intend on reprinting any of these maps for use in a publication, please read our Use Conditions.