Stephen Quake (left) and Euan Ashley review genetic risk factors that Ashley and colleagues found in Quake's genome. Norbert von der Groeben/Stanford School of Medicine hide caption

itoggle caption Norbert von der Groeben/Stanford School of Medicine

Smog covers downtown Los Angeles on Wednesday. A new report finds that the Los Angeles area had the worst levels of ozone, based on figures from 2006-2008. Nick Ut/AP hide caption

itoggle caption Nick Ut/AP

Mike Kasavich, a lifelong coal miner, exits "the hole" after a 10-hour morning shift at the Mathies coal mine in western Pennsylvania. Black lung disease is increasing among miners, yet they are struggling to get disability reimbursement for the illness. Spencer Platt/Getty Images hide caption

itoggle caption Spencer Platt/Getty Images