"The Supreme Court refused on Tuesday to consider reducing the Environmental Protection Agency's authority to set air quality standards, leaving intact a tough new limit on sulfur dioxide emissions in a victory for the Obama administration."

"Without comment, the court decided not to hear an appeal by Grupo Mexico SAB's Asarco LLC unit of a lower court ruling that upholds a 2010 EPA rule limiting sulfur dioxide in the air to 75 parts per billion over one hour.
 
Short-term exposure to sulfur dioxide has been linked to respiratory problems."

Jonathan Stemper reports for Reuters January 23, 2013. [2]