Small piston aircraft were exempted from today’s “endangerment finding” issued by the U.S. Environmental Protection Agency, but the finding means new regulations will be forthcoming to target greenhouse-gas emissions from many jet engines, the agency said. “Aircraft are the third largest contributor to GHG emissions in the U.S. transportation sector, and these emissions are expected to increase in the future,” said Janet McCabe, EPA’s acting assistant administrator for air and radiation.
Source: avwebEPA Says Airline Emissions "A Threat To Human Health"