An odor advisory was issued Sunday for the Salton Sea area in Riverside County due to elevated levels of a gas that smells like rotten eggs, according to state air regulators. The advisory was issued for the Coachella Valley and will remain in effect until at least Monday because of winds from the south, with peak concentrations of hydrogen sulfide emissions occurring in the morning hours, the South Coast Air Quality Management District said in a statement. “Hourly average concentrations of hydrogen sulfide peaked [Sunday] morning at 239 parts per billion immediately downwind of the Salton Sea – at a monitor close to the shore, in an area with little population,” the district said.