A strong sulphuric odor that repelled residents of Riverside County and neighboring counties was confirmed today to have emanated from the Salton Sea.
"We now have solid evidence that clearly points to the Salton Sea as the source of a very large and unusual odor event," said Barry Wallerstein, executive officer of the South Coast Air Quality Management District.
The stench hung on the air in Riverside and numerous other Inland Empire cities -- from Moreno Valley to Murrieta -- Monday morning after drifting into the region Sunday night. Complaints came "from a very wide area including the Inland Empire and much of the Los Angeles Basin," according to an AQMD statement, which noted that "fish kills, algae blooms and other biologic conditions in lakes can cause strong odors."
According to the agency, which monitors pollution levels in the region, technicians took air samples and field inspectors used odor surveillance techniques to isolate the location of the stink and results "showed a clear progression of hydrogen sulfide levels, with the highest concentrations found at the Salton Sea and decreasing concentrations found as the distance increased from the sea."
"This progression, or gradient, points to the Salton Sea as the source of the odor," Wallerstein said.
Organic decay, or dying plant and animal life, produces the unmistakable rotten-egg scent, officials said, pointing out that thunderstorms over the inland desert Sunday likely carried the stench from the stagnant Salton Sea to points farther west.
Riverside County Supervisors John Benoit and Marion Ashley noted during today's Board of Supervisors meeting that the foul smell has been a recurring problem in the Coachella and Imperial valleys for years and now the rest of Southern California was getting a taste of it.
The supervisors said the problem underscores the need for steps to improve conditions at the site.
According to the AQMD, the hydrogen sulfide fumes, which dissipated by early Monday afternoon, did not pose a health threat.