Smoke from Canadian wildfires cloaks eastern US with haze

Thick skies and an acrid campfire smell hung over the capital Washington, with parts of the mid-Atlantic region reaching "Code Maroon," the highest category of the Air Quality Index (AQI), signaling hazardous conditions.

This exceeded some of the most polluted cities in the world in South Asia and China, leading many residents to wear masks to protect their health. Though improving, conditions aren't expected to return to normal until the weekend.

More than 111 million people in the United States were living under air quality alerts due to the fires, the Environmental Protection Agency said Thursday.

"Millions of Americans are experiencing the effects of smoke resulting from devastating wildfires burning in Canada, another stark reminder of the impacts of climate change," Biden said in a statement.

He added he was sending extra resources to Canada, including "additional firefighters and fire suppression assets such as air tankers," on top of 600 American personnel sent in May.

The smoke blanketing the nation's capital was not immune to the city's usual political machinations

White House spokesman Andrew Bates hit out at congressional Republicans, saying the majority "subscribes to debunked conspiracy theories that deny the existence and nature of climate change," even amid worsening weather events.

The White House postponed an outdoor Pride event, although a parade and festival this weekend remain on course for now. The National Zoo meanwhile announced it would close "for the safety of our animals, our staff and our guests."

The Washington Nationals, the capital's Major League Baseball team, announced it was postponing its afternoon game against the Arizona Diamondbacks.

Hemadri Vora, a 42-year-old tourist from Mumbai, was spending the day with her family in Washington after a visit to New York.

"It's a little disappointing," she told AFP at the Washington Monument, but added she was used to similar pollution levels back home. "Obviously, the pictures are not going to be very clear."

Public schools in the capital canceled all outdoor activities including recess, physical education, athletic practices and competitions.

The Federal Aviation Administration meanwhile said low visibility had forced it to take steps to "manage the flow of traffic safely into New York City, DC, Philadelphia and Charlotte."

Environmental groups were also quick to draw attention to climate change, which is creating warmer, drier conditions that are increasing the risk and extent of wildfires.

"This is the climate crisis, here and now, causing dangerous air pollution and threatening the health of millions of people," said May Boeve, Chief Executive of 350.org.