The South Coast Air Quality Management District has issued a special high particle pollution alert due to the Fourth of July fireworks display, in effect until 11:59 p.m. Friday, July 5, 2024. (Image courtesy of AQMD)

Due to the aftermath of the Fourth of July fireworks, the South Coast Air Quality Management District has issued a special particle pollution alert that will cause hazardous conditions in some areas on Friday, July 5.

The agency said fireworks during Independence Day celebrations often result in some of the worst air quality days of the year.

The warning, which covers parts of Los Angeles, Orange, San Bernardino and Riverside counties, is in effect until 11:59 p.m. Friday.

In some areas, including much of the South Bay and Orange County, air quality was in the medium AQI (Air Quality Index) range as of 9 a.m. Friday.

At the same time, air quality in many areas of Los Angeles, the San Fernando Valley, the San Gabriel Valley and the Inland Empire ranged from “unhealthy” to “hazardous.”

The worst areas Friday morning were around Glendora and Azusa, as well as parts of West Covina toward the mountains, where air quality was hazardous. Just outside of this area, including Pomona, Montclair, Claremont, Duarte and Arcadia, air quality was measured as very unhealthy.

Air quality was also very unhealthy in the eastern San Fernando Valley as well as in Burbank and Glendale on Friday morning.

Most of Los Angeles, the rest of the San Gabriel Valley, and the Inland Empire as far east as Redlands experienced air quality that was either unhealthy or unhealthy for sensitive groups.

According to AQMD, particles emitted by fireworks (including backyard fireworks) contain metallic air pollutants, creating even more dangerous conditions.

And backyard fireworks can lead to even higher levels of particulate matter in the neighborhoods where they are set off, further worsening air quality measured by AQMD's regional equipment, the agency said.