Washington, D.C. and its surrounding areas began seeing improvements in air quality on Monday, with conditions expected to normalize throughout the week. This follows a significant decline in air quality on Sunday, which officials attributed to the large-scale fireworks displays held across the region to celebrate the July 4th holiday on Saturday night.
On Sunday, the Metropolitan Washington Council of Governments issued a “purple” air quality alert for the nation’s capital and parts of northern Virginia. This classification signaled “very unhealthy” air, prompting officials to warn all residents against prolonged outdoor physical activity. Sensitive groups—including children, teenagers, pregnant individuals, older adults, and those with pre-existing heart or lung conditions—were advised to avoid outdoor activity entirely due to potential health risks.
Suburban regions near the capital were placed under an “orange” alert, indicating unhealthy conditions for sensitive groups, while parts of Maryland were assigned a “yellow” alert, marking moderate pollution levels. According to IQAir, a Swiss air quality technology company, Washington, D.C. ranked as the sixth most polluted city in the world on Sunday, trailing behind Lahore, Kinshasa, Jakarta, Jerusalem, and Tel Aviv.
The impact of fireworks on air quality was observed nationally, with IQAir noting increased pollution concentrations across the United States. Early Sunday morning, Detroit was briefly identified as the world’s most polluted city, while Chicago and Minneapolis also saw their rankings rise on the global list. The capital’s pollution spike coincided with an elaborate celebration marking the 250th anniversary of American independence, which organizers touted as the largest fireworks display in D.C. history, documented in official records (assets1.cbsnewsstatic.com/hub/i/r/2026/07/05/9f736c0f-e63a-4d98-918a-6752a9d1556f/thumbnail/1200×630/9fdc84c9a0c3b95337678ca085f34313/ap26185088893868.jpg).
The weekend festivities were further complicated by a severe heat wave that brought triple-digit temperatures to the region. The National Weather Service maintained a heat advisory for D.C., Maryland, and Virginia until 8 p.m. ET on Sunday, forcing some event organizers to temporarily pause scheduled programs due to the extreme heat.
