Hundreds of wildfires burning in the Pacific Northwest and British Columbia this week are filling the sky with smoke and making it impossible to get a fresh breath of air. In a city known for its jaw-dropping views of the mountains, the smoke was so thick in Seattle on Monday that it blotted the skyline and turned the sun an unsettling shade of red. It’s also causing health concerns, prompting an air quality rating of “very unhealthy.”

From Alki Beach Park, a popular spot west of downtown, the image captured in many Instagram and postcards shots was that of a skyline obliterated by smoke.

The smell filled the air, and ash covered vehicles in a layer of grainy white. More than 300 flights were delayed at Seattle-Tacoma International Airport because of low visibility. Many of the city’s most popular parks sat nearly vacant Monday afternoon into the evening. Stretches of roadway and bike paths popular among the after-work biking crowd were virtually empty. A few people who ventured outside — fishermen and dog walkers — wore masks.

Vancouver had the worst air quality in the world on Monday. Seattle’s air was fourth-worst.

In a city where only 1 out of 6 homes has central air, even people without respiratory problems were at risk as the smoke seeped through windows left open to cool things down. The temperature Tuesday was forecast to hit 90 degrees.

Three large fires were the primary culprits on Monday, all Type 1 incidents, which is the highest level of complexity. The smoke from the three fires merged in the wind Monday and wafted over the Seattle-Tacoma metro area.

The plume was so thick it could be seen from space, writhing in the wind and embedded in a brown blanket of ash and smoke that covered the western half of the state.

“Speechless,” said KIRO7 meteorologist Morgan Palmer as he tweeted a photo from the channel’s sky cam, “mainly because I’d have to open my mouth and breathe in to talk. And that seems like not a great idea.”

There are a lot of different things floating in wildfire smoke, but the tiny solid particles — known as particulate matter or PM — are the most significant hazards to health, according to the Environmental Protection Agency. Children, the elderly and pregnant women are at the highest risk for complications from smoke inhalation. The smaller the particles are, the more dangerous they become. When inhaled, tiny particles can enter the lungs — and even the bloodstream.

“The effects of smoke range from eye and respiratory tract irritation to more serious disorders, including reduced lung function, bronchitis, exacerbation of asthma and heart failure, and premature death,” an EPA guide for public health officials states.

You can wear a mask to protect your lungs, but the EPA says “dust masks” aren’t going to cut it. “Scarves or bandanas (wet or dry) won’t help, either,” according to the website. “Particulate masks known as N-95 or P-100 respirators will help, but they must fit well and be used correctly. They are sold at many hardware and home repair stores and online.”

The smoke filled Safeco Field on Monday night when the Mariners hosted the Astros. The Mariners chose to practice in the batting cages before the game to limit smoke inhalation. Fans watched the Mariners pull off a win through the haze.

“The smoke coated their throats and lungs; it made their eyes water, and threatened to choke them, much like the team’s recent struggles fought to snuff out a once-promising season,” Lookout Landing wrote after the game. (Ouch.)

Smoke will be an issue in western Washington state through Tuesday, but a shift in the wind is coming. Starting Wednesday, winds will be out of the south and west, which will push the smoke away from Seattle. British Columbia and Alberta will be socked with Washington wildfire smoke starting Wednesday.

Feature image by Sigma Sreedharan.