Sulfates and nitrates work together to increase the
acidity of rain, while ammonium works to lower the acid
level. Look at various parts of the United States and
consider how these three factors work together to determine
the pH levels for different parts of the country. Neutral
pH is 7, and precipitation with a pH level below 5 is
considered acid rain.
! Use the buttons on the map to switch between the
sulfate, nitrate, ammonium, and pH views of the United
10. Explain how sulfate, nitrate, and ammonium levels
work together to produce the observed pH level in central
11. Explain how sulfate, nitrate, and ammonium levels
work together to produce the pH level in the Panhandle
region of western Oklahoma.