The Hidden Toll of July Fourth Fireworks

It’s no secret that fireworks can cause some serious air pollution, in the United States as well as in other countries where holiday displays are common, like China and India. But not everyone is equally at risk from the noxious particles that suffuse the sky during our pyrotechnic light shows. In California, for example, vulnerable populations are more exposed to fireworks pollution on the Fourth of July.

That’s according to a recent study published in the International Journal of Environmental Research and Public Health on air pollution exposure across the state due to Independence Day fireworks. At its peak, the smoke from these events can be comparable to that from wildfires, the study found. The authors also showed that fireworks smoke may be creating an additional—albeit short term—health risk for communities already disproportionately burdened by air pollution: Urban ones with higher rates of asthma, more older residents, and a greater percentage of children under 10. These areas also tended to have more Black and Hispanic residents than those with less Fourth of July air pollution.

The high-risk communities identified in the study have “perpetual exposure to hazardous environmental toxins,” says Aisha Dickerson, an environmental epidemiologist at Johns Hopkins University who wasn’t involved with the paper. “This aggravates an already prevalent and persistent issue.”

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Fireworks don’t just produce colorful, crackling light displays: They also create puffs of smoke. What’s less widely known is that the smoke can be dangerous. Fireworks smoke includes particulate matter—an asthma trigger and a leading contributor to respiratory disease—as well as a cocktail of toxic metals like strontium, barium, and lead.

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The researchers found that Fourth of July fireworks pollution, although transient, can be significant. In Orange County, hourly levels of PM2.5 rose up to three times higher than normal on July 4, 2019, while Los Angeles County pollution levels soared up to 10 times higher than average on July 4, 2020. The festivities in the L.A. metro area last year produced as much smoke as a moderate wildfire.

Vulnerable populations appear to be more exposed to this pollution: On average, the authors found that PM2.5 spikes around the Fourth of July were higher in urban census tracts in Southern California, areas that tend to have higher asthma rates, more older individuals and small children, and more Black and Hispanic residents, compared with rural census tracts and those further north. Southern California metropolitan areas also tend to have fewer restrictions on municipal fireworks shows and looser oversight of at-home fireworks use compared with their counterparts in Northern California.

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Dickerson says she’d expect to see a similar pattern of exposure to fireworks-related air pollutants elsewhere around the country.

“A lot of the fireworks displays typically happen in the bigger cities, especially along coastal communities, and lower income [minority] communities typically are closer to those ports,” she says.

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Given all the risks, Wu suggests it’s time for city and local governments to more aggressively crack down on illegal fireworks—something several California cities are attempting to do this year—and consider shifting to other types of public displays, such as drone light shows. {snip}

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