Scientists have revealed that air pollution may be ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth for a significant reduction in intelligence. Research conducted for the World Health Organization (WHO) in China showed that air pollution was responsible for ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth falls in student ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth scores for languages and ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth . The Chinese study is called, "The ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth of exposure to air pollution on cognitive ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth ". It was published in a journal called, "Proceedings of the National Academy of Sciences". The ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth took place over a ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth of four years. Researchers analyzed verbal and arithmetic tests taken by 20,000 people of all ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth . They said: "Polluted air may impede cognitive ability as people become ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth ." Researchers say their study is a ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth to the rest of the world, especially to those who live in ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth . The WHO says over 91 per cent of the world population live in ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth with toxic air. Air pollution is ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth the fourth highest cause of deaths worldwide. The researchers discovered that the ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth people were exposed to polluted air, the greater was the ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth to their intelligence. They equated the impact of air pollution to losing a year's ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth of education. For those aged over 60, this could be the ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth of several years of lost education. Researcher Dr Xi Chen warned: "There is no ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth to solve this issue. Governments really need to take ages areas arithmetic cities concrete currently damage equivalent impact longer notable older performance period responsible shortcut study test warning worth measures to reduce air pollution."