Smoke from Canadian wildfires blankets the skies of the Northeast for days starting Tuesday, and when paired with hot, humid conditions expected during that same time, some may have trouble breathing. The smoke is coming from wildfires burning primarily in Ontario. The combination of high press ure over the Central U.S. and low pressure over Eastern Canada will funnel the smoke over the Great Lakes into the Northeast. A slight haze in the air Tuesday will get thicker on Wednesday and stay thick Thursday. Expect air quality to suffer because of the smoke. Some of it will stay aloft, but there will be ground-level smoke particle concentrations that could irritate your respiratory system if you are sensitive. It would be advisable to avoid being outside for any length of time while smoke hovers over the region. View this post on Instagram A post shared by NBC New York (@nbcnewyork) The smoke comes at the same time that high pressure is bringing extreme heat to the region, which is another reason to limit time outdoors. ...read more read less