Contrary to what many people may think, the air quality in cities across the US has been getting better for many years. Since 1990 mercury released from human sources is down 60 percent, benzene—a toxic greenhouse gas—is down 66 percent, and lead pollution which impacts brain development has dropped by 84 percent, according to a newly released EPA report. While there is still much work to be done to make US cities cleaner, the authors say, the report shows that we are headed in the right direction.