Every year there is a major air pollution spike on the fourth of July, with small particles (PM2.5) surging during the evening. To illustrate, here are the concentrations of small particles (PM2.5, sizes less than 2.5 microns) for June 15 to July 15th for 2018 and 2019. Huge upticks of pollution for late July 4th and early July 5th.
2018 These high levels of small particles are quite unhealthful, aggravating ailments such as asthma and heart disease.
There are, of course, two sources of the such fireworks pollution: large community displays and personal fireworks. The former typically use large shells propelled by large mortars, injecting more particles higher into the atmosphere. Personal fireworks are more numerous and widespread, but the densest concentrations of pollutants are near the surface.
I have always wondered: what are the relative contributions of the professional/community displays versus personal fireworks in terms of contributions to air pollution and the big spikes in particles (like shown below). It was difficult to secure an answer because both happened at the same time.
But this year, a controlled experiment is going to take place on July 4th: most community fireworks displayed were cancelled, while there are reports of “healthy” sales of personal fireworks. Will there be a similar peak in pollutants? Will air quality decline more because folks will go for big shows to provide distraction from all their current troubles? We will know by next Sunday.