Thu. Dec 7th, 2023

Valid Sunday July 05, 2020

This advisory is in effect through Sunday Afternoon. South Coast AQMD will issue an update if additional information becomes available.

Air quality is currently poor in portions of the South Coast Air Basin due to Independence Day firework celebrations. As of noon on Sunday afternoon, Air Quality Index (AQI) levels are Unhealthy in portions of Los Angeles and San Bernardino counties due to elevated fine particulate matter concentrations. Residents are encouraged to visit or download the South Coast AQMD mobile app at to monitor conditions in real-time.

During the overnight and early morning hours, AQI levels reached the Hazardous category in portions of Los Angeles and Orange counties. Fine particulate matter concentrations are expected to decrease throughout the day on Sunday with increased atmospheric mixing. As a result, AQI levels are expected to decrease to Moderate levels in coastal locations and Downtown Los Angeles. In inland locations such as the San Fernando Valley, the San Gabriel Valley, and the Inland Empire, afternoon ozone will likely result in AQI levels in the Unhealthy for Sensitive Groups or Unhealthy categories. See for details.

Fine particulate matter levels on July 4th and July 5th are typically among the worst (highest) days of the year in the South Coast Air Basin. Fireworks are known to emit high levels of particulate matter (PM2.5 and PM10) as well as metal air pollutants, all of which can contribute to negative health effects. The smoke and combustion products from fireworks add to the fine particles already present in the Basin that are primarily caused by motor vehicles, as well as fugitive dust and industrial emissions. Breathing of fine particulate matter can lead to a wide variety of cardiovascular and respiratory health effects such as heart attacks, asthma aggravation, decreased lung function, coughing, or difficulty breathing and may lead to premature death in people with heart or lung disease.

Areas of direct impacts and poor air quality may include portions of:

  • Los Angeles County: Central Los Angeles (Area 1),
  • Northwest Coastal LA County (Area 2),
  • Southwest Coastal LA County (Area 3),
  • South Coastal LA (Area 4), Southeast LA County (Area 5),
  • West San Fernando Valley (Area 6), East San Fernando Valley (Area 7),
  • West San Gabriel Valley (Area 8),
  • East San Gabriel Valley (Area 9),
  • Pomona-Walnut Valley (Area 10),
  • South San Gabriel Valley (Area 11),
  • South Central Los Angeles County (Area 12),
  • Santa Clarita Valley (Area 13),
  • San Gabriel Mountains (Area 15)
  • Orange County: Northern Orange County (Area 16)
  • Riverside County: Corona-Norco (Area 22),
  • Metropolitan Riverside County (Area 23)
  • San Bernardino County: Northwest San Bernardino Valley (Area 32),
  • Southwest San Bernardino Valley (Area 33),
  • Central San Bernardino Valley (Area 34),
  • East San Bernardino Valley (Area 35)

By Editor

The New Santa Ana blog has been covering news, events and politics in Santa Ana since 2009.

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