Canadian wildfires cause unhealthy air conditions in large parts of United States

June 6 (UPI) -- Several states are facing unhealthy air conditions Tuesday under the haze produced by Canadian wildfires.

Alaska, Pennsylvania, New Jersey, New York, Massachusetts and Michigan are among the states that are under warnings from the National Weather Service because of hot and dry conditions that could produce even more fires.

The agency warns that the combination of wind, low relative humidity, warm temperatures and "extremely dry fuel moisture -- will contribute to extreme fire behavior."

In northeast Pennsylvania, there is concern that lightning from isolated thunderstorms could spark a fire in the driest areas.

Residents in these at-risk areas are urged to avoid activities that could lead to stray embers causing a fire, such as grilling. Activities that produce friction -- such as using a chainsaw -- also might create a spark that could ignite a fire.

For the second day in a row, much of the United States east of the Missouri River is experiencing substandard to poor air quality because of smoke produced by wildfires in Canada in recent weeks.

Alberta, Nova Scotia, British Columbia and now Quebec have become wildfire hot spots, as well.

According to AirNow, a government resource that reports air quality data, the worst air quality is in the northeastern United States. New York and New Jersey are in unhealthy air conditions with air quality index ratings of more than 150. An AQI reading over 100 is considered unhealthy.

The air quality in states such as Pennsylvania and Missouri is rated as unhealthy for sensitive groups, including people with respiratory illnesses.

Canada's wildfire season is expected to be among its worst, with 413 active wildfires across nearly the whole country. About 26,000 people have been ordered to evacuate. Wildfire season usually lasts from May to September.