Thick smoke billowed from forest fires in Quebec's backcountry on Monday, sparking smog alerts in Montreal and the US city of Boston, and putting city firefighters in Ottawa on alert, officials said. Fifty-two blazes burned north of Montreal, eight of them out of control, blackening thousands of hectares of forests in Quebec, the Quebec forest fire protection unit (Sopfeu) said. In Ottawa, residents awoke to a strong smell of smoke, and fire crews were dispatched to all corners of the capital city to monitor approaching fires. In Montreal, a smog alert was announced for much of the southern part of the province, along the Saint Lawrence seaway. South of the border, the US National Weather Service issued air quality alerts for the border states of Maine and New Hampshire, as well as Massachusetts, with the thickest smoke reaching Cape Cod and Nantucket. 'Smoke from a number of large fires in southern Quebec has begun to move over portions of southwest New Hampshire... as well as eastern Massachusetts,' the US National Weather Service said. By evening, winds were expected to shift back to a west to southwest direction and 'push the smoke back out to sea,' it added. The Quebec public health agency, meanwhile, urged 'vulnerable people to take precautions,' noting that 'smog affects mostly people with respiratory or cardiac illnesses, and children with asthma.' More than 1,200 firefighters, including 200 from other provinces and the United States, were sent into the backcountry on Monday to try to douse the flames. They were backed by several aerial water bombers. More than 900 square kilometers of Quebec forests have been destroyed by fire since the start of spring, amid record high temperatures and dry weather. 