What happens to firework pollution after the party?

Building on a study they carried out in 2020, a team of researchers at NYU Langone Health have taken a close look at the effects of Macy’s 4th July firework display, last year.

In the earlier study they analysed air quality samples taken across the United States by the Environmental Protection Agency (EPA) over 14 years, finding that levels of toxic metals were higher in samples collected around Independence Day and New Year’s Eve than at any other time of the year.

In the latest research, they focussed on the effect of the 60,000 fireworks that Macy’s launched into the sky on Independence Day, measuring air quality for an extended period of time after the event. 

The measurements for the 2023 event were:

• PM2.5 levels at a sampling site closest to the Macy’s show peaked at: 3,000 µg/m3
• Two other nearby locations peaked at: 1,000 µg/m3
• New York City’s daily average: 15 µg/m3
• New York when affected by wildfire smoke in June 2023: 460 µg/m3

It was found that air quality took several hours to return to normal levels at most of the sampling sites, with those closest to the display in Midtown Manhattan, taking as long as 12 hours.

The team also looked at EPA data from Boston, Philadelphia, and Washington, DC, finding a similar pattern in which  pollutant levels were elevated for between three and 12 hours before returning to normal.

Lead author Terry Gordon, PhD, a professor in the Department of Medicine at NYU Grossman School of Medicine said: ‘Our findings suggest that major firework displays can create a temporary spike in air pollution that may pose a health risk to both humans and the environment.’

The team also tested the water in the East River, where the levels of metals used in fireworks – such as lead, nickel, and antimony – were found to have doubled after the event.

Senior author Antonio Saporito, BA, a doctoral student at NYU Grossman School of Medicine said: ‘While these findings may seem alarming, firework shows can still be enjoyed. Wearing an N-95 or KN95 mask is a good way to avoid inhaling smoke when standing near a display, especially for children and for those with preexisting heart and lung problems.’