Intro
Acid rain is a common problem in the United States because many mechanical/industrial processes produce non-metal oxide gases, for example CO2. These gasses combine with the water in the atmosphere to produce acids which then fall to the ground as acid rain. The acid ends up in lakes and kills the aquatic life; it also is harmful to plant life on land.
Different types of pollution are more harmful because they produce stronger acids, these strong acids tend to be more potent and their impact on nature is more easily seen. The pH of the acid rain depends upon how much this acid dissociates (breaks up). Stronger acids break up into their respective ions more and have lower pHs. The pH is lower because the stronger acid will yield a higher concentration of H+ per the same amount of gas added.