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Cleaner Air

January 16, 2018

Declining organic aerosols are good for human health.



Declining organic aerosols. I’m Bob Hirshon and this is Science Update.

The Clean Air Act of 1990 saved tens of thousands more lives than expected, according to MIT scientist David Ridley and his colleagues, reporting in the Proceedings of National Academy of Sciences. The regulations made power plants, vehicles and furnaces cleaner, but weren’t expected to significantly reduce organic aerosols. That’s because those pollutants have many non-human sources, like wildfires. But Ridley found that these compounds dropped far more than was anticipated, because the Clean Air Act reduced levels of various atmospheric ingredients that allow the pollutants to form later.

DAVID RIDLEY (Massachusetts Institute of Technology):

It’s great that we can see the added benefits coming from these regulations, and that they’ve had a clear impact on the air that we’re breathing.


The result was over 80,000 more lives saved than the original EPA estimates. I’m Bob Hirshon, for AAAS, the science society.

Story by Matt Miller and Bob Hirshon