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Name: Collin
Status: Student
Grade: 4-5
Location: PA
Country: United States
Date: April 2006

Why is the pH in acid rain lower in Washington DC than it is in Lancaster, PA?

The pH of rain is not constant. It depends upon geography, local conditions, time of day, and a long list of other variables. In general, the rainfall in metropolitan areas tends to be more acidic (lower pH) than more rural areas. But that is a generalization that has many exceptions because gases that tend to form acid rain (SO2, NO2, ...) can move many hundreds of miles before the acids formed by the reaction with water vapor falls to Earth.

Vince Calder

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