The Fourth of July once again ranked among the worst air quality days of the year nationwide. South Coast AQMD recorded elevated levels of fine particulate matter (PM 2.5) throughout South Coast Air Basin on the evening of July 4th through the early afternoon of July 5th. In some areas, the Air Quality Index (AQI) reached the “Hazardous” category, indicating the highest level of health risk.

This year, the average PM2.5 levels in the South Coast Air Basin were the sixth highest for Independence Day in the past decade. Monitors in the Los Angeles region and western Inland Empire detected air quality at Unhealthy to Hazardous levels, with the highest concentration recorded in Los Angeles.

These findings follow a consistent upward trend of air pollution from Fourth of July celebrations over the past 15 years, largely driven by commercial and backyard fireworks use. Personal “backyard” fireworks, despite being illegal in Los Angeles County, are large contributors to localized pollution spikes in the region.

Fireworks are known to emit high levels of PM2.5 and PM10 as well as metal air pollutants, all of which can contribute to negative health effects. Breathing high levels 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 and difficulty breathing.

During periods of poor air quality, residents can reduce how much pollution they are breathing by keeping outdoor activities brief and avoiding vigorous physical activity. Air conditioning with a filter and/or an air purifier can also help reduce indoor pollution levels. Residents can check their outdoor air quality with the South Coast AQMD app or at www.aqmd.gov.