South Coast Air Quality Management District officials warned Thursday that a heat wave will bring unhealthy smog levels to parts of Southern California.
An ozone advisory will take effect at 10 a.m. Friday and remain in effect until 8 p.m. Sunday.
According to the agency, the Air Quality Index is expected to reach the “Unhealthy for Sensitive Groups” category or higher each day through Sunday evening in the interior portions of the South Coast Air Basin, including the San Fernando, Santa Clarita and San Gabriel valleys, and the Saddleback Valley area.
Air quality is forecast to reach the “Unhealthy” category or worse in Glendora during the advisory period.
Health officials advised residents, particularly children, older adults and people with asthma or other respiratory conditions, to limit prolonged or strenuous outdoor activity when air quality reaches unhealthy levels.
Residents can monitor air quality conditions in real time using the South Coast AQMD mobile app or by visiting the agency’s website at www.AQMD.gov.