The smell of rotten egg is part of a natural out gassing process by the Salton Sea.
Valley residents were warned Thursday by regional air quality officials to expect the smell of rotten eggs, the result of very high levels of hydrogen sulfide being emitted by the Salton Sea.
The gas is part of “natural processes” occurring in the Salton Sea and the smell could be spread by high winds, according to the South Coast Air Quality Management District.
State standards suggest hourly average concentrations of hydrogen sulfide outdoors should not exceed 30 parts per billion. Those levels peaked at 117 parts per billion this morning, downwind of the Salton Sea, according to the AQMD.
Levels measured by a second monitor in the nearby town of Mecca also exceeded the state standard, with a reading of 129 parts per billion.
At 30 parts per billion, some people could experience headaches and nausea. But the symptoms would be temporary and no long-term health effects would be expected, according to AQMD officials.
This is the second hydrogen sulfide alert this week. A similar alert was issued Monday, though levels were much lower.