New York, Sep 28 : Short-term exposure to air pollution, defined as occurring within five days of the stroke, can significantly increase the risk of stroke, according to a new study. In the study, researchers from University of Jordan in Amman looked at pollutants such as nitrogen dioxide, ozone, carbon monoxide and sulphur dioxide as well as different sizes of particulate matter, including PM1, which is air pollution that is less than 1 micron (μm) in diameter, as well as PM2.5 and PM10. The team found higher concentrations of nitrogen dioxide were linked to a 28 per cent increased risk of stroke; higher ozone levels were linked to a 5 per cent increase; carbon monoxide had a 26 per cent increase; and sulphur dioxide had a 15 per cent increase. Along with this higher concentration of PM1 was linked to a 9 per cent increased risk of stroke, with PM2.5 at 15 per cent and PM10 at 14 per cent. Their findings, published in the journal Neurology, is based on a review of 110 studies that included more than 18 million cases of stroke. The team also found that higher levels of air pollution were linked to higher risk of death from stroke. Higher concentrations of nitrogen dioxide were linked to a 33 per cent increased risk of death from stroke, sulphur dioxide, a 60 per cent increase, PM2.5, a 9 per cent increase and PM10, a 2 per cent increase. 'There is a strong and significant association between air pollution and the occurrence of stroke as well as death from stroke within five days of exposure,' said Ahmad Toubasi, study author, MD of the University of Jordan in Amman. 'This highlights the importance of global efforts to create policies that reduce air pollution. Doing so may reduce the number of strokes and their consequences,' Toubasi added. /IANS