Large amounts of smoke from Canada's forest fires moved southward into the US on the evening of the 15th, causing more than 115 million people in the midwestern and northeastern regions of the US to be threatened by unhealthy air quality. This situation may continue until the 17th. According to data from the US air quality monitoring website at www.airnow.gov, the index of fine particulate matter harmful to health in the air in Chicago, Illinois rose to 489, reaching a “dangerous” level. At one point, this index reached 500 in parts of Michigan. Residents in some parts of the two states say they can smell smoke in their homes. The US National Weather Service has issued air quality alerts for affected areas. The smog situation in the Midwest and Northeast regions of the United States is expected to continue until the evening of the 16th or the 17th.

Large amounts of smoke from Canada's forest fires moved southward into the US on the evening of the 15th, causing more than 115 million people in the midwestern and northeastern regions of the US to be threatened by unhealthy air quality. This situation may continue until the 17th. According to data from the US air quality monitoring website at www.airnow.gov, the index of fine particulate matter harmful to health in the air in Chicago, Illinois rose to 489, reaching a “dangerous” level. At one point, this index reached 500 in parts of Michigan. Residents in some parts of the two states say they can smell smoke in their homes. The US National Weather Service has issued air quality alerts for affected areas. The smog situation in the Midwest and Northeast regions of the United States is expected to continue until the evening of the 16th or the 17th.