SAN DIEGO — The recognizable sewage smell in the South Bay is hydrogen sulfide gas. It can cause headaches, lung irritation, nausea, dizziness, vomiting and is linked to serious long-term health issues.
San Diego County's Air Pollution Control District launched a website showing hydrogen sulfide levels detected in Nestor and San Ysidro. There are currently two air quality monitoring systems, one at Berry Elementary School in Nestor and another at the San Ysidro Fire Station 29.
"This new dashboard provides historical data for the last week, and that is updated on a daily basis," Air Pollution Control Officer Paula Forbis said. "And in addition to that, there's a button, a clock icon, that people can click to get hourly data that is updated every hour."
Hydrogen sulfide readings are measured by parts per billion, or ppB, and are divided by an odor advisory system. One ppB is equivalent to a single drop of water in a 10,000 gallon pool.
Green means 0 to 4.9 ppB of gas is detected. There's usually no symptoms or smell associated.
Yellow is 5 to 29.9 ppB. Sensitive groups may notice the smell at this level.
Orange is when the ppB hits 30 or higher.
"It's a level at which the vast majority of the public will smell the odors and a large percentage made bothered by them," Forbis said.
An odor advisory will be sent to the public with safety recommendations, including staying indoors, closing windows and using air purifiers. You can sign up for odor advisory alerts here.
The most extreme level is purple, at more than 27,000 ppB detected, which would require emergency response.
"Our role is really to focus on monitoring for air quality and providing that information to the appropriate public health authorities if we start to see levels of hydrogen sulfide get really elevated," Forbis said.
In a few weeks, another monitoring system will be place at the Imperial Beach Civic Center.
"We're also obtaining funding for a mobile monitoring van that will be able to supplement these three stationary monitors with an instrument that can provide instantaneous read of hydrogen sulfide," Forbis said.
Plans are also in the works to provide some South Bay residents with air purifiers.