In the Chicago area, air quality ranged from very unhealthy to hazardous.<\/p>\n
New York, NY (AP<\/a>) \u2013 Heavy, pungent\u00a0wildfire<\/a>\u00a0smoke darkened skies in the U.S. on Thursday from the Great Lakes to parts of the East Coast, reducing visibility and prompting warnings that breathing the air outside could\u00a0be dangerous.<\/a><\/p>\n Officials in many cities urged residents to stay inside or wear masks outside as air quality reached unhealthy to hazardous levels, meaning it\u2019s unhealthy for anyone, regardless of health conditions. The smoke is coming from\u00a0fires<\/a>\u00a0that are\u00a0burning primarily in Canada<\/a>\u00a0but also in northern Minnesota. A lingering high pressure system has trapped the smoke close to the ground, said Steven Freitag, a National Weather Service meteorologist in Detroit, where air quality was among the worst in the world for major cities.<\/p>\n \u201cSure enough, it arrived in force here and it\u2019s really pretty extreme levels,\u201d said Freitag, who noted that visibility in some areas was reduced to a half mile.<\/p>\n \u201cIt\u2019s scary,\u201d Omar Mitchell, 50, said as he looked to the sky. He wore a mask while walking to his restaurant in Detroit. \u201cYou don\u2019t know necessarily what the side effects may be. That\u2019s days or months later.\u201d<\/p>\n Microscopic particles can lodge deep in the lungs and enter the bloodstream, leading to heart and lung problems and contributing to other long-term health issues.<\/p>\n The air stinks and the sky glows yellow in some places<\/p>\n All of Michigan and much of Minnesota were under a\u00a0hazardous air quality<\/a>\u00a0alert. In the Chicago area, air quality ranged from very unhealthy to hazardous.<\/p>\n National Weather Service meteorologist Jake Petr said even if winds from the northwest clear skies as expected later this week, the smoky air could keep returning until the fires are out. That could take months, until it snows in Canada and northern Minnesota, officials have said.<\/p>\n Bill Ostrowski, 76, wore a mask as he walked through downtown Chicago, where wildfire smoke shrouded skyscrapers. \u201cIt stinks. It\u2019s not a good sign when you wake up in the morning and you can smell the air,\u201d said Ostrowski.<\/p>\n In St. Paul, Minnesota, the sky was \u201cglowing yellow,\u201d said Brent Williams, head of the soil, water and climate department at the University of Minnesota. The area \u201ccould be looking at weeks to months of continued smoke and flare-ups off and on as the winds blow in different directions,\u201d he said.<\/p>\n A study published this year found that long-term exposure to tiny particles from wildfire smoke contributed to an average of 24,100 deaths a year in the lower 48 states. Long-term exposure can make existing health problems worse and lead to a range of chronic and deadly issues, including respiratory illness, cardiovascular and neurological diseases, and premature death.<\/p>\n New York City cancels activities and hands out masks<\/p>\n In the New York City area, a thick haze tinged the morning sky orange and yellow and\u00a0partly obscured<\/a>\u00a0Manhattan\u2019s skyline.<\/p>\n City officials opened cooling centers as health officials urged New Yorkers to limit strenuous and prolonged outdoor activities. The city\u2019s schools, parks and other agencies moved activities indoors, rescheduled events and adjusted operations. State officials distributed tens of thousands of face masks at transit hubs and other major locations.<\/p>\n Gwen Moseley, 65, was among the first patrons at Rosedale Library in Queens to take advantage of the free masks, saying she\u2019s on the road much of the day working as a therapist for children with autism.<\/p>\n \u201cWho wants to be breathing this? It\u2019s not healthy,\u201d Moseley said as she waited to meet a young client. \u201cWhen I\u2019m out walking, I can feel the scratchiness in my throat.\u201d<\/p>\n Smoke eased a bit but was expected to thicken again by late afternoon or evening, possibly lasting overnight, weather service meteorologist Maureen Hastings said. She said it might move south for a while on Friday but return at night.<\/p>\n The state Department of Environmental Conservation warned that there was a potential for temporary spikes of \u201cvery unhealthy\u201d air quality from Buffalo in the state\u2019s western corner to Rochester by Lake Ontario, Syracuse in the central region and down to the greater New York City area.<\/p>\n Philadelphia officials urged people to avoid strenuous activity and stay inside or wear N95 or KN95 masks outside.<\/p>\n \u201cToday is not the day to start your marathon training plan,\u201d said Dr. Palak Raval-Nelson, the city\u2019s public health commissioner.<\/p>\n Minnesota fires are spreading<\/p>\n In Minnesota, forest rangers on Thursday combed a remote wilderness area for anyone who might still be there days after wildfires led to its closure.<\/p>\n Officials closed the Boundary Waters along the U.S.-Canada border on Tuesday. At the time, 6,000 to 10,000 people were inside, but Superior National Forest staff estimated Wednesday that they\u2019d reached 90% of them, said Karen Harrison, a spokesperson for state and federal agencies involved in the response.<\/p>\n She said Thursday that smoke is making it difficult for helicopters to fly and that fires are spreading despite firefighting efforts.<\/p>\n \u201cThere will be fire on the landscape until fall, and some fire will be burning until snow cover,\u201d Harrison said.<\/p>\n The Royal Canadian Air Force successfully evacuated 11 Minnesota teenagers and four staff members Wednesday from wildfires in an Ontario provincial park about 175 miles (282 kilometers) north of the Minnesota border.<\/p>\n ___<\/p>\n Webber reported from Fenton, Michigan. Associated Press reporters Ed White in Detroit, Jacqueline GaNun in Lansing, Michigan, and Cybele Mayes-Osterman in Chicago contributed to this report.<\/p>\n ___<\/p>\n The Associated Press\u2019 climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP\u2019s\u00a0standards<\/a>\u00a0for working with philanthropies, a list of supporters and funded coverage areas at\u00a0AP.org<\/a>.<\/p>\n