In 2010, 3.2 million people died prematurely from outdoor air pollution, mainly in Asia, and mainly from soot and other pollutants from diesel cars and trucks. That means outdoor air pollution is now a bigger health risk than high cholesterol — and, along with obesity, one of the fastest-growing health risks in the world. indoor air pollution, largely from smoky coal- or wood-burning cook stoves in countries in Africa, and in India, caused some 3.5 million premature deaths in 2010. China currently has one car for every 17.2 people. In the United States, there’s one car for every 1.3 people. If China were to catch up with the U.S. car ownership rate, the country would field a billion vehicles all by itself.
Brad Plumer, "Air Pollution Now Kills More People Then High Cholesterol", The Washington Post, Dec. 20, 2012. http://www.washingtonpost.com/blogs/wonkblog/wp/2012/12/20/air-pollution... [verified 4/17/14]