Nearly all air quality in Washington was listed as unhealthy or worse on Monday, with the Pacific coast the only exception.ДЄs large cities dealt with unhealthy air for a second summer in a row, experts warn that it could become more common as the American West faces larger and more destructive wildfires because of heat and drought blamed on climate change.

Forecasters expect some relief and air circulation by late Wednesday. Wednesday for all of Western Washington because of smoke from large wildfires in British Columbia and on the east slopes of the north Cascades. The National Weather Service in Seattle issued an air quality alert through 5 p.m. West, blotting out mountains and city skylines from Oregon to Colorado, delaying flights and forcing authorities to tell even healthy adults in the Seattle area to stay indoors. вЂњI would not be surprised at all if these events did become more frequent in the future.Smoke from wildfires clogged the sky across the U.S. вЂњWe fully expect that youвЂ™re going to see more situations where smoke, from fires occurring farther away, is going to travel long distances and affect people in other parts of the country,вЂќ Jesse Berman, a University of Minnesota air quality expert, tells the Associated Press. Air quality in cities from Toronto, New York, and Philadelphia also reached unhealthy PM levels, the New York Times reports. In New York City, AQI levels reached above 170, a level unsafe for sensitive populations with existing respiratory conditions and healthy people, reports Live Science. Any values above 100 are considered unhealthy. Particulate matter levels are measured using the Air Quality Index (AQI), with a scale ranging from 0 to 500. Breathing excessive amounts of PM2.5 increases the risk of asthma attacks, strokes, and heart attacks, National Geographic.

PM less than 2.5 micrometers in diameter (PM2.5) poses the greatest health risk. These tiny particles can reach deep into the lungs, pass into the bloodstream, and cause severe respiratory illness and distress, National Geographic reports. PM less than ten micrometers in diameter can only be seen using a microscope. Some of the particles can be so tiny that they can be inhaled. Particulates are directly released into the air from smokestacks, fires, construction sites, and unpaved roads. Particulate matter (PM), or particle pollution, are a mix of liquid droplets and particles of dust, dirt, soot, or smoke that can be seen with the naked eye. The images from July 20 and 21 displayed a band of smoke traveling eastward and particulate matter concentrations, or soot, masking North America, reports Harry Baker for Live Science. Satellite images released on July 23 by NASAвЂ™s Earth Observatory revealed the extensity of the smokeвЂ™s reach from the various wildfires. The fire threatened a total of 5,000 homes, and 2,000 households had to evacuate, reports Gillian Flaccus and Sara Cline for the Associated Press. Ignited by a lightning strike on July 6, t he Bootleg Fire was so large it created its own weather, prompting even more lightning and releasing vast amounts of smoke, reports Nadja Popovich and Josh Katz for the New York Times. The largest fire is OregonвЂ™s Bootleg Fire, which had already charred 400,000 acres, or roughly an area nine times the size of Washington D.C, per National Geographic. The billowing smoke resulted from nearly 300 active wildfires currently ravaging British Columbia, CanadaвЂ™s westernmost providence, and 80 fires blazing through the American west. вЂњWhat theyвЂ™re experiencing on the East Coast from our West Coast fires shows itвЂ™s a nationwide and a global problem,вЂќ says Mary Prunicki, Stanford UniversityвЂ™s director of air pollution and health research, to National Geographic.

Skylines from Boston to North Carolina faded behind an eerie haze, and air quality alerts urged residents thousands of miles away from the wildfires to stay inside as winds blew the smoke eastward, reports Sarah Gibbens for National Geographic. The billowing smoke resulted from nearly 300 wildfires currently ravaging British Columbia, CanadaвЂ™s westernmost providence, and 80 fires blazing through states in the Western United States.ДЄs regions across the western United States and parts of Canada face an intense early wildfire season, its effects are being witnessed on the opposite side of the country as far east as the Atlantic Ocean.

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