[Big Dave]

"I'm sure the air in the L.A. basin isn't as clean as it was pre-industrial age."

The Spanish missionaries referred to the San Fernando Valley as the "Valley of Smoke." What do you suppose that air quality was in NYC in Washington's day? Horse manure in summer and wood smoke in the winter. What of Boston in Lincoln's day? Horse manure, woodsmoke, and coal smoke.


"Even Minnesota has had air quality alerts- this in the age of strict pollution controls."

If you ratchet down standards far enough, even rural air will cause air pollution alerts.



What does EPA air monitoring data tell about pollutant concentrations?