Poor air quality took over much of Southern California Tuesday following a night of July Fourth fireworks.

The South Coast Air Quality Management District issued a particulate advisory for the greater Los Angeles area and into the Coachella Valley through Tuesday afternoon.

Fireworks are known to emit high levels of particulate matter and metal air pollutants, all of which can contribute to negative health effects, according to AQMD, which monitors air pollution in Los Angeles, Orange, San Bernardino and Riverside counties.

The Air Quality Index scale showed “unhealthy” and “very unhealthy” levels for much of L.A. and Orange County on Tuesday afternoon. Before firework shows began Monday, the levels mostly hovered at “moderate” or “good” levels, according to the Los Angeles Times.

Last year, Fourth of July fireworks created the second-highest air pollution levels from the holiday in the last decade.

The use of personal “backyard” fireworks may lead to localized fine particulate matter concentrations
above observed regional levels, the advisory said.

Light winds are expected in the South Coast Air basin after dusk, increasing pollutant build-up.

“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,” AQMD said. “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.

The use of consumer-grade “backyard” fireworks can also spark wildfires, which can be a major source of fine particulate matter, the advisory stated.

Breathing in fine particulate matter can lead to a wide variety of cardiovascular and respiratory health
effects, AQMD warned, 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.

Air pollution levels are typically worse in areas with widespread consumer grade fireworks use. To avoid
increasing PM2.5 levels even further, South Coast AQMD recommends that the public avoid burning
wood during periods of poor air quality.