Topline
Washington, D.C. is facing a “very unhealthy” air quality alert for Sunday morning, hours after the massive fireworks display billed as the largest ever for America’s 250th anniversary left pollutants in the air—exacerbating the poor air quality after a day of triple-digit temperatures on the Fourth of July.
The Fourth of July fireworks display in the capital impacted the amount of fine particulate matter in the atmosphere.
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Key Facts
Authorities in Washington D.C. and northern Virginia issued “code purple” air quality alerts for Sunday after the fireworks show in the early morning hours—meaning the air in the capital could reach “very unhealthy” levels for everyone.
The air quality index recorded at D.C.’s McMillan Reservoir on Sunday morning reached 157 by 10 a.m. EDT, indicating an “unhealthy” level of fine particulate matter in the air.
Parts of D.C. already saw “very unhealthy” air quality index levels on Sunday morning—the King Greenleaf Recreation Center south of the National Mall peaked at an air quality index of 288 around 5 a.m. EDT, but dropped down to 127 as the morning progressed, according to data from AirNow.
People at risk include individuals with heart disease, asthma, older adults, children and pregnant women, although higher air quality index values can also indicate unhealthy levels of pollution for everyone, even those outside the at-risk groups.
During periods of “very unhealthy” air quality, AirNow recommends people avoid outdoor exercise and “long, intense activities.”
What Is Impacting the Air Quality?
The air quality index measures the amount of fine particulate pollution in the air. These particles are 2.5 micrometers or smaller, and can be distributed into the atmosphere by wildfires, industrial processes, power plants and other sources of pollution, according to AirNow. These tiny particles can cause health risks for people in at-risk groups. Warm temperatures can also impact air quality, according to the Centers for Disease Control. D.C. is still under a heat advisory, with the National Weather Service predicting heat index values (or the “feels-like temperature”) between 105 and 109 degrees until Sunday evening. Although the air quality is often poor after fireworks displays, it has improved quickly after past displays, Capital Weather reported on Sunday.
Key Background
Washington, D.C.’s annual Fourth of July fireworks were delayed this year, originally scheduled to go on at 11 p.m. after being pushed back to accommodate a headlining speech from President Donald Trump. The event was delayed even later on Saturday—Trump ended up taking the stage around 11 p.m., the New York Times reported, speaking for about 35 minutes before the show. The fireworks didn’t begin until about midnight. The Trump administration was aware of concerns the display might cause “very unhealthy” levels of air pollution, according to internal National Park Service documents reviewed by the Washington Post last week.