aid some patients might not be emotionally ready to leave the hospital after three days.
((MUSIC BRIDGE))You are listening to the Special English program SCIENCE IN THE NEWS on VOA. This is Warren Scheer with Bob Doughty in Washington.
American officials have announced that production of a chemical commonly used to kill insects will be stopped. Studies have shown the substance could be harmful, especially to children.
The chemical, chlorpyrifos, (klor-PYE-ruh-fahs) has been widely used for more than thirty years. It is used in agriculture. And it is used in hundreds of products to kill insects in homes and gardens. About three-thousand six-hundred studies and reports have examined the health effects of chlorpyrifos -- also known by the name Dursban.
Carol Browner is the head of the Environmental Protection Agency. She noted that chlorpyrifos is part of a group of older pesticide products known to have health risks. Mizz Browner said people who live or work near areas treated with the chemical may develop disorders of the nervous system.Last month, the Environmental Protection Agency signed an agreement with six companies that make chlorpyrifos. Under the agreement, production of the chemical for use in homes, schools, hospitals, stores, parks and children's play areas will be halted by the end of this year. The agreement also cancels or sharply limits the amount of chlorpyrifos permitted on some foods eaten by children, such as tomatoes, apples and grapes.
Chlorpyrifos used in buildings to kill insects called termites will be banned by the end of next year. At that time, sales of chlorpyrifos products in the United States will be barred.
((MUSIC BRIDGE))An Israeli study has shown that air pollution from cities and industry can reduce rain and snowfall. It says the problem appears to be linked to the number of pollution particles in clouds. Daniel Rosenfeld of Hebrew University in Jerusalem organized the study. His findings were reported in the publication Science.
Mr. Rosenfeld observed air pollution over Australia, Canada and Turkey from cities and factories. He used images provided by a satellite orbiting Earth. The satellite has instruments that can measure clouds and rainfall.
Raindrops form in clouds with little or no pollution when water in the air collects around dust particles. The study notes that about one-million small droplets are required to form a drop of water large enough to fall to earth.Mr. Rosenfeld observed the movement of the air pollution as it floated away from cities, power production centers and oil treatment centers. He found that heavily polluted clouds do not produce as much rain as cleaner clouds. He says this is because polluted clouds are made of only very small water droplets.
Mr. Rosenfeld says polluted clouds have too many dust particles. The large number of particles results in the formation of too many water droplets that are too small.
They are not big enough to form raindrops. The smaller droplets also are slower to freeze and do not easily form ice particles for snow.Last year, Mr. Rosenfeld found that burning trees and other plants also reduces rainfall amounts. This can be a problem in areas where forests are cleared for development.
Science magazine published a commentary on the findings. Owen Toon of the University of Colorado at Boulder said the study is the first direct evidence that pollution from cities and factories affects rain. He says more studies are needed to show if the effect found over Australia, Canada and Turkey is found in other areas.
This SCIENCE IN THE NEWS program was written George Grow. This is Bob Doughty.And this is Warren Scheer. Join us again next week for more news about science in Special English on the Voice of America.