Concentrations of individual fine particulate matter components in the USA around July 4th

Abstract

Fireworks emit particulate matter (PM) air pollution. Laboratory and epidemiologic studies have linked exposure to PM with cardiovascular and respiratory effects. Although it was reported that the mass of total PM with a nominal mean aerodynamic diameter less than or equal to 2.5 μm (PM2.5) is elevated on July 4th and 5th, no studies to date have used national, multi-year air quality monitoring data to determine which individual PM2.5 components increase due to July 4th fireworks. To evaluate this, we compiled and analyzed 24-h average PM2.5 air quality measurements collected by the Environmental Protection Agency’s Chemical Speciation Network monitors positioned at 379 urban sites across the USA over the years 2000 to 2014. By combining all individual daily mean PM2.5 concentrations recorded and viewing the arithmetic mean concentrations over time, we observed sharp and statistically significant increases in the concentrations of the firework-related chemicals barium, chlorine, copper, magnesium, potassium, and strontium on July 4th, which persisted through July 5th. There were also modest, but still statistically significant, increases of the concentrations of the firework-related components aluminum, arsenic, antimony, chromium, phosphorous, sulfur, titanium, and zinc on July 4th. Concentrations of elemental and organic carbon, calcium, cesium, iron, nickel, and sodium did not significantly increase on July 4th. These findings provide important information about changes in ambient air quality around Independence Day in the USA.