The air quality concerns in San Diego's South Bay region, long plagued by foul smells and health complaints from residents, have now been scientifically linked to the polluted Tijuana River. A study by UC San Diego's Scripps Institution of Oceanography and other partners found toxic gases being released into the air, validating locals' concerns. According to Scripps Oceanography, hydrogen sulfide levels were measured at concentrations significantly higher than what is considered normal for an urban area, sometimes exceeding safe exposure limits by nearly 70 times.
In addition to the hydrogen sulfide—or "sewer gas"—issue, scientists identified hundreds of other gases that can impact air quality. However, further research is needed to determine if their levels exceed safety thresholds. Benjamin Rico, a study's lead author and UC San Diego PhD candidate, explained via the Scripps Institution of Oceanography news, "Our results validate the community voices that have been saying that air quality near the Tijuana River has been a problem for many years." The high gas concentrations are particularly concerning, considering their potential health risks, such as headaches, nausea, and respiratory symptoms.
The research, conducted over three weeks, used air quality instruments strategically placed in the neighborhood of Nestor, close to a section of the river notorious for strong odors. These measures were combined with river flow data and atmospheric modeling, capturing the spread of pollutants across the community. The instruments detected exceedingly high levels of hydrogen sulfide, peaking at 4,500 parts per billion (ppb), a stark contrast to the California Air Resources Board's one-hour standard of 30 ppb, which is already associated with adverse health effects.
The findings substantiate years of health complaints and broken breaths for residents, especially those near Berry Elementary School. Paula Stigler Granados, an environmental health scientist at SDSU's School of Public Health, pointed out that "this level is too high for chronic exposures as 30 parts per billion is already associated with headaches, nausea, respiratory symptoms and other adverse health effects, particularly among vulnerable populations." Interim solutions now include free air purifiers and an online dashboard provided by the San Diego County and the San Diego Air Pollution Control District to monitor hydrogen sulfide levels and provide immediate alerts when levels spike, per Scripps Institution of Oceanography.
On a broader scale, the study underscores the need for upgraded treatment infrastructure and revised water management policies, both locally and internationally. With the Tijuana River serving as a cautionary tale, the authors also advocate for globally updating air quality models to include emissions from contaminated water sources. Kelley Barsanti from NSF NCAR, who led the analysis on the other gases present, stated through the Scripps Institution of Oceanography report, "There are multiple sources of waste entering the Tijuana River and a multitude of other hazardous gases that area residents are potentially inhaling."
Amidst an ecological crisis, funding from federal sources like the National Science Foundation and NOAA has driven the study. This financial backing enabled Scripps Oceanography to link basic aerosol science to community outcomes. U.S. Representative Scott Peters emphasized the study's significance: "For decades, our region has endured the dangerous public health effects from untreated sewage and industrial waste in the Tijuana River." He added via the Scripps Institution of Oceanography news, "This peer-reviewed study links water pollution to worse air quality with clear and convincing data."
