At about 8 p.m. on the Fourth of July last year, air pollution levels across Chicago started to climb. Just a few hours later, as Chicagoans watched brightly colored fireworks explode in the sky, the city reached a level of air pollution more than four times the hourly average of a normal summer evening.
The hours between 9 p.m. and midnight on July 4, 2021, ranked as the most intensely polluted hours the city experienced at any point over the past year, according to an analysis of data on Chicago’s air quality. The new analysis is part of an ongoing project by MuckRock, WBEZ and the Sun-Times.
While the findings, from first-of-its-kind data from Microsoft air sensors installed in more than 100 locations across Chicago, are not surprising, experts say they underscore how holiday traditions like fireworks can contribute to poor air quality in a short amount of time. Researchers found similar spikes in particulate matter, or PM2.5, in Los Angeles on the Fourth, and noted it produced as much smoke as a moderate wildfire. Like Los Angeles, Chicago has among the worst air pollution of any major city in the U.S., and some of the country’s highest rates of childhood asthma, resulting in a dangerous mix for those most vulnerable.
In response to the findings, the Chicago Department of Public Health said in a statement that while it’s against the law to use fireworks in Chicago and Illinois, those laws are ineffective when they are not “regionally applied and surrounding states are more lenient in the sale and use of fireworks.”
Most types of fireworks, including bottle rockets and Roman candles, are illegal in Illinois but can be purchased in neighboring Indiana.
The city’s health department also said the new data “highlights how disproportionately elevated PM2.5 is in the South and West Sides and can affect the health of vulnerable populations, emphasizing the importance of addressing environmental justice and education about the hazardous effects of using fireworks.”
Microsoft has led a project to build a hyperlocal air quality sensor network citywide. Precious Esie, a recent doctoral graduate of Columbia University’s Mailman School of Public Health program, was a Microsoft research intern last summer when she noticed the spike in air pollution on the Fourth of July and the unequal effect on certain neighborhoods.
“Pollution levels were particularly elevated in areas on the South and West Sides of the city,” said Esie, who also noted the higher rates of asthma and other respiratory diseases in those areas.
Last year, Adam Niermann, a 43-year-old Irving Park resident and father of three, was just arriving at a park near his home as the city’s air began to fill up with fireworks and pollutants. Niermann’s neighborhood usually follows the same Independence Day traditions: a kid’s bike parade, backyard barbecues and families waiting for the sun to go down and the fireworks to start.
Chicago’s official fireworks go off over the water near Navy Pier, often before the official holiday, with this year’s display taking place on Saturday. Much of the smoke and haze Chicagoans observe on the evening of the Fourth come from individual caches and neighborhood fireworks shows.
At a park near Niermann’s home, families and kids from around the neighborhood…
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