Elevated levels of hydrogen sulfide prompt odor advisory

The South Coast Air Quality Management District issued an odor advisory for the Coachella Valley on Thursday due to elevated levels of a gas that smells like rotten eggs.

Officials with the SCAQMD said hourly levels of hydrogen sulfide (H2S) peaked Wednesday night at 46 parts per billion immediately downwind of the Salton Sea.

The state standard for outdoor levels of hydrogen sulfide is 30 parts per billion averaged over one hour. At that level, people can experience symptoms such as headaches and nausea. However, officials said the symptoms are only temporary with this level of exposure and won’t cause any long-term effects.

A monitor located further downwind in Mecca didn’t see the higher H2S levels so the Coachella Valley may not be directly affected. But, officials said if southeasterly winds do occur, some areas could briefly experience the odors.

The advisory is in effect until midnight, but if the conditions warrant, SCAQMD will issue another advisory Friday.

More information about hydrogen sulfide

The South Coast Air Quality Management District monitors hydrogen sulfide at two locations in the southeastern Coachella Valley, one very close to the Salton Sea and the other is in Mecca.

The potential for Salton Sea odors to occur is more likely as the winds shift, especially in the late summer months in the early morning and late afternoon, according to the release.