Pennsylvania: Pittsburgh correspondent Kevin Begos was first to report that the amount of carbon dioxide released into the atmosphere in the U.S. had fallen to its lowest level in 20 years. Begos, who monitors federal technical reports, began exploring the subject after noticing that energy-related CO2 emissions for the first four months of this year fell to about 1992 levels. He found that the primary reason was the switch by many power plants from dirty coal to cleaner, cheaper natural gas.