Environmental groups describe the study as added reason for government programs to regulate emissions.
“It seems particulates were suppressing rainfall in Atlanta,” said the study’s author, Jeremy Diem, an associate professor of geosciences.
He compared data from nine weather stations inside the city to nine others in places like Athens, LaGrange and Cedartown to discover that rainfall was suppressed in Atlanta until the anti-pollution law began to take effect.
Ordinarily, water molecules in clouds cling to dust particles of all sizes, and when they grow big enough, they fall as rain. But in the 1950s and ‘60s when industrial activity was accelerating in the South and before passage of the 1972 Clean Air Act, that process was disrupted, according to Diem’s research.
The tiny specks of soot and other particles spewing out of smokestacks at factories and power plants were roughly the same size, resulting in small droplets rather than raindrops heavy enough to fall to the ground.
Diem believes the same thing happened in other cities. Atlanta was a good candidate for study because weather patterns around it and the comparison area aren’t affected by mountains or oceans.
Would even stricter pollution regulations yield more rain and help the city’s quest for adequate water supplies?
There’s no more improvement to be had, the scientist said.
“I think we got it,” Diem said. “It seems like once we got below a certain level, additional particulate reduction seems unimportant.”
Still, the data could be helpful to developing countries like China where pollution is rampant and regulations are few.
Environmental activists in Georgia were already welcoming it Thursday.
“This is further evidence that government has a critical role to play in protecting Georgians and our environment,” said Elena Parent, executive director of the Georgia Watch advocacy organization. “Georgia’s decision makers should take note, particularly in light of our state’s continuing problems with drought, and strengthen existing environmental protection laws. I hope that sound science such as this would be taken to heart by all of Georgia’s leaders, no matter their political hue.”
But veteran environmental lobbyist Neill Herring, who works for the Sierra Club and other groups, has reservations about the reception the study will get with those state leaders.
“I can only suppose that it will be of marginal use. It may serve to sway a few who are on the margins of the anti-regulatory majority, but the fact that official GOP policy seems to be that ‘regulation kills jobs’ makes it only somewhat useful,” he said.