Urban air pollution is a global problem. Researchers at Columbia University studying clogged air and pregnancy in New York found pollution reduced intelligence and increased the risk of behavioral problems when babies reached school-age. Beijing is among the worst offenders. Air quality in the Chinese capital deteriorated beyond World Health Organization safe limits every day last month as smoke from coal-powered generators, factory emissions, car fumes, and dust amassed over the city of 20 million people. Download a copy of the article here or read it online.