A group of international scientists at the Hebrew University of Jerusalem found that heavy air pollution reduces rainfall, local daily the Jerusalem Post reported Monday.

The research team, led by Prof. Daniel Rosenfeld of the Institute of Earth Sciences, developed a model that shows how particles in the air influence cloud formation and rain. The findings were published Friday in the latest issue of the journal Science.

The model showed that a certain number of aerosol particles in the air increases rainfall, but an overabundance of them retards it.

While some aerosol particles form the nuclei of the clouds themselves, too many aerosols act as a sunblock, keeping water from evaporating to form clouds.

The research team discovered that there was a specific curve to the production: rainfall first rises, then plateaus and then sharply drops off in the presence of too many aerosols.

Rosenfeld said that the amount of aerosols is the critical factor controlling how the energy is distributed in the atmosphere.

"These results have great significance for countries where rainfall is scarce and can be easily affected by over-production of aerosols," Rosenfeld was quoted as saying.

"Our study should act as a red light to all of those responsible for controlling the amounts of pollution we release into the atmosphere."

(Xinhua News Agency September 9, 2008)