Synopsis

The inspiration for this graphic came from reading Bill Bryson's description of the threat of acid rain in his (otherwise amusing) account of his hike of the Appalachian Trail, A Walk in the Woods: Rediscovering America on the Appalachian Trail. As a nature lover, I wondered why one rarely hears about the effects of acid rain.

It turns out that the problem of acid rain has been largely solved by eliminating the pollution that gives rise to it. The National Atmospheric Deposition Program (NADP) has roughly thirty years of data collected through its National Trends Network (NTN). As can be seen from the graphic, the pH3 of rain in the U.S. has become far less acidic, on average, over the past 2 decades.