Washington - Clouds of pollution from power plants and other sources may prevent rain from falling in downwind areas, a study suggests.
Daniel Rosenfeld of the Hebrew University of Jerusalem reports in the journal, Science, that satellite data shows plumes of pollution from plants in Australia, Canada and Turkey persist for miles downwind from the industrial sites.
Rosenfeld said moisture in the air condensed on these particles, but never formed droplets big enough to fall to the ground as rain or snow.
Natural particles in the atmosphere played a key role in the formation of rain and snow. But these natural particles were larger than the ones exhausted from the smoke stacks of many power plants, the study said.
Rosenfeld said satellite instruments taking data over a power plant near Adelaide, Australia, showed that rain condensed and fell from natural clouds, while the man-made smoke stack plumes nearby failed to produce any precipitation.
"The satellite data provides evidence connecting urban and industrial air pollution to the reduction of precipitation," Rosenfeld said in the study. "Such results might indicate that human activity may be altering clouds and natural precipitation on a global scale."
Owen Toon, a scientist at the University of Colorado, Boulder, said that Rosenfeld's study would help researchers understand how aerosol, or airborne, pollution affected rain clouds.
"Such knowledge may allow us to estimate how widespread the aerosol interaction with cloud precipitation may be in our globally polluted world," Toon said in Science. - Sapa-AP