The Air Quality Management District has released a statement regarding the sulfur-like odor that has blanketed the Inland Empire and parts of Los Angeles and Orange counties.
From the AQMD:
Field inspectors with the South Coast Air Quality Management District are in the field today investigating possible causes of widespread sulfur odors. Since around midnight last night, AQMD has received more than 100 calls reporting a strong, foul rotten egg/sulfur odor. Residents have complained from a very wide area including the Inland Empire and much of the Los Angeles Basin.
Fish kills, algae blooms and other biologic conditions in lakes can cause strong odors. Industrial facilities such as wastewater plants also can cause sulfur odors. At this time AQMD hasn’t confirmed any source as the cause of the widespread odor. AQMD will issue updated information later in the day if more information is available. AQMD is the air pollution control agency for Orange County and major portions of Los Angeles, San Bernardino and Riverside counties.
http://www.aqmd.gov/news1/index.html