Current air is 2 – 5 X cleaner than air at start of 20th century
Interesting report on air quality and emissions from the Desert Research Institute and PopSci.com.
According to a study by the Desert Research Institute, pollutant levels
at the beginning of the 20th century were two to five times higher than
current levels of pollution. Researchers attribute the decrease in
pollution levels to the advent of more efficient coal-burning
technologies, as well as legislation aimed at reducing emissions. (emphasis added)
Good to see the science is now backing what we have been saying for years.