How Acidic Is Your Rain?
ES1807  Local Trends

The next step in analyzing your local data is to graph the trends of NH4+, NO3+, and SO42- and compare them with the pH trend. Using the same scale for all three ions will allow you to directly compare their relative amounts and see how they change over time.

Examine the range of your data values for all three of the ions to set the upper and lower limits of your scale, then create an appropriate scale on the left side of the graph. Graph the three lines for your NH4+, NO3+, and SO42- data.

  !   Move your cursor over the graph to view an example of the pH trend over the same time period. As the pH scale has a very different range of values, it is shown on the right side of the graph.

Example graphs of acid rain data for Casper, Wyoming.
Examine the range of pH values in your data to set the upper and lower limits of your scale. Make an appropriate scale on the right side of the graph. This will allow you to see how pH changes over time, and you'll discover how the three different ions contribute to the changing pH levels. Graph the line for your pH data.

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