Scientists found that air pollution may be for a big in intelligence. Research conducted in China showed that air pollution was responsible for big in test scores for and arithmetic. The study is called, "The of exposure to air pollution on performance". It was published in the "Proceedings of the National Academy of Sciences" . The study took place over four . Researchers analyzed speaking and arithmetic tests taken by 20,000 people of all . They said: "Polluted air may impede cognitive as people become older."
The is a warning to the of the world, especially those in cities. Over 91 per cent of the world population live in with toxic air and air pollution is the fourth highest of global deaths. Researchers discovered that the longer people were exposed to polluted , the greater their intelligence went down. They said air pollution caused a year's worth of education. For those over 60, this could be years. A researcher warned: "There is no to solve this issue. Governments really need to take concrete to reduce air pollution."