"The effect of long-term exposure to dirty air on the risk of miscarriage has been analysed previously. Studies from Brazil to Italy to Mongolia found a link, but others failed to do so. However, the latest study is the first to assess the impact of short-term exposure to air pollution. It found that raised levels of nitrogen dioxide (NO2) pollution that are commonplace around the world increased the risk of losing a pregnancy by 16%. “It’s pretty profound,” said Dr Matthew Fuller, at the University of Utah’s department of emergency medicine and one of the research team. “If you compare that increase in risk to other studies on environmental effects on the foetus, it’s akin to tobacco smoke in first trimester pregnancy loss.” NO2 is produced by fuel burning, particularly in diesel vehicles."