4th of July Fireworks Celebrations Lead to Highest PM2.5 Levels in Over a Decade

Data from South Coast AQMD’s monitors found that air quality in the South Coast Basin was substantially worse during the 2020 Independence Day weekend than any year in the last decade. Based on video footage and the cancellation of most large public events, it is likely that a combination of increased use of personal “backyard” fireworks and stagnant air led to trapped air pollution that lingered for longer than usual.

Overall average concentrations of fine particulate matter (PM2.5) in the Basin were 70 percent higher than previous years between 7 p.m. on July 4th to 7 a.m. July 5th. Monitors picked up an even greater increase in the maximum hourly measurements of PM2.5, with the highest concentrations detected at the Central Los Angeles, North Hollywood and Anaheim stations. Some instruments were found to have so much particulate matter residue on them that it resulted in readings so high the data could not be properly validated.

During the overnight and early morning hours of July 4th-5th, air quality reached Very Unhealthy and even Hazardous levels in portions of Los Angeles and Orange counties.

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. Breathing 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.

Visit our Independence Day Weekend Air Quality page for charts and information on the heavy metals and other pollutants that impacted our air quality:

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