Lung-damaging ozone pollution in Los Angeles reached its highest levels in a generation and set records in other parts of Southern California during the blistering Labor Day weekend heat wave, air quality readings show.
Ozone pollution spiked to 185 parts per billion in downtown Los Angeles at midday Sunday, according to South Coast Air Quality Management District monitoring data. It was the highest hourly reading in Southern California since 2003 and the highest in downtown L.A. in 26 years.
The eight-hour average ozone level in downtown L.A. was 118 ppb, “very unhealthy” on the Air Quality Index and far above the federal standard of 70 ppb. The last time ozone readings were that high in downtown L.A., by either measure, was in 1994, at a time when emissions were much higher and smog dramatically worse.
In Orange County, the eight-hour average ozone reading in Mission Viejo was 123 ppb, the highest on record since monitoring began at that location in 2000. Compton's eight-hour reading was 115 ppb, its highest since monitoring began there in 2008.