NEW YORK , Aug. 6, 2024 /PRNewswire/ -- In 2023, roughly 60,000 firework shells exploded above Manhattan's East River as part of Macy's Fourth of July show. The resulting air pollutant levels were many times higher in the hours after the display than those seen when smoke from a Canadian wildfire had blanketed the area a month before.
This is according to the results of a new study, led by researchers at NYU Langone Health, which measured air quality just before and after the Independence Day event, one of the largest in the United States . Tiny particles of hazardous metals and organic compounds peaked at 3,000 micrograms per cubic meter at an air sampling site near the show and topped 1,000 micrograms per cubic meter at two other nearby locations. By comparison, New York City's average daily fine-particle concentration is 15 micrograms per cubic meter and reached 460 micrograms per cubic meter from the wildfire smoke in June 2023 .
The team also found that air quality took several hours to return to baseline levels for most sampling sites, with those closest to the display, such as in Midtown Manhattan, taking as long as 12 hours. In addition to fine-particle air pollutant increases, water samples collected from the East River had more than double the levels of metals sometimes used to give fireworks their vibrant colors, such as lead, nickel, and antimony, than before the celebration. Notably, the researchers had shown in earlier experiments using rodents and human tissue .