The US Geological Survey maintains the On-line Data and Reports on Acid Rain, Atmospheric Deposition and Precipitation Chemistry Web site. Visitors to the site can use the interactive US map to retrieve monitoring station data including precipitation-weighted means and total wet deposition in the form of trend plots, annual data summaries, and annual to daily data sets. Other resources available include isopleth maps in the form of animations that display the spatial patterns of sulfate, nitrate, and ammonium concentrations in the National Trends Network of monitoring stations from 1985 to 2000. For further reading, those interested can peruse the numerous publications available on the site including a recent article entitled "The Effects of Atmospheric Oxygen Deposition in the Rocky Mountain of Colorado and Southern Wyoming."