CHICAGO — Researchers analyzed the amount of soot on birds in museums from Rust Belt cities to track air pollution over the last 135 years.
A new paper in the Proceedings of the National Academy of Sciences shows the discoloration of birds in museum collections can be used to estimate the amount of black carbon air over time, Science Daily reported.
Researchers from The Field Museum and the University of Chicago sampled over a thousand birds collected over the last 135 years to find out and quantify the effects of soot in the air in Rust Belt cities like Chicago, Detroit and Pittsburgh.
To track changes in sootiness, the scientists photographed the birds and measured the light reflected off of them.
They found that older birds were dirtier and new birds were cleaner. The team discovered that soot on birds closely tracks the use of coal over time.
Researchers also pointed out that even though newer birds are cleaner, it doesn't necessarily mean U.S. air is less polluted. Many of the pollutants released into the atmosphere today aren't as easily tracked as soot.
