Background

The combination of significant transboundary sewage flows and deficient wastewater treatment infrastructure in the United States and Mexico, has created an environmental crisis affecting air, water, and soil quality. The untreated wastewater and sewage flows have created strong odors for South Bay residents that are impacting their quality of life. The odors are caused by hydrogen sulfide (H2S), a colorless gas that with a pungent odor that resembles a “rotten egg” smell.

In response to the increased levels of H2S the San Diego County Air Pollution Control District (SDAPCD) secured $100,000 thru an Environmental Protection Agency (EPA) grant to purchase AQ Mesh sensors track H2S trend levels. However, when SDAPCD was in the process of installing the sensors a combination of increased levels of untreated sewage flows due to a wastewater pump failure and heat waves significantly aggravated the odors, prompting a surge of complaints.

After conducting an investigation, SDAPCD issued a Notice of Violation to U.S. International Boundary and Water Commission (IBWC) and its contractor, Veolia for causing a public nuisance. Details regarding the investigation can be found on odor investigations section.

Subsequently, SDAPCD has improved its air quality monitoring by installing Teledyne T101 monitors that track H2S data and will be publicly available online via a real-time dashboard that is in development. The public will also be able to sign-up for odor advisory notifications when H2S levels reach sustained levels that have been outlined in the Community Hydrogen Sulfide Guidance. In the interim, SDAPCD has implemented a H2S data dashboard that is updated daily and can be found on our air quality monitoring section, as well as more information about the Community Hydrogen Sulfide Guidance.