Minor increases in urban air pollution can provoke heart attacks, new international research indicates. A study of seven European cities and regions, including London, Madrid, Paris, and Rome, found that when sulfur dioxide levels rose even slightly, hospital visits for coronary problems increased over the following 48 hours. The research, published in the European Heart Journal, is expected to put pressure on government officials to further crack down on polluters. “When this link between pollution and heart disease was first seen, everyone thought there had been some mistake,” said Jon Ayres of Aberdeen University. “But we are now building up a body of evidence that there is an effect, and at quite low levels.”

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