BOSTON (WHDH) - The National Weather Service has issued an Air Quality Alert as smoky haze coming from fires elsewhere in the U.S. and Canada settle over much of the Bay State.

The alert is in effect until midnight Tuesday and excludes the southeastern part of the state including Plymouth and Bristol counties and the Cape and Islands.

RELATED: Hundreds are still under evacuation orders as the nation’s largest wildfire chars more than 400,000 acres

The Massachusetts Department of Environmental Protection said particle pollution content is on the rise and is expected to be at an unhealthy level for sensitive groups.

Sensitive groups include people with heart or lung disease such as asthma, older adults, children, teenagers, and people who are active outdoors. People with either lung disease or heart disease are at greater risk from exposure to particle pollution.

“Actually we were thinking that maybe something was on fire because it was that hazy,” local resident Maria Smith said.

Many fire departments said they have been fielding calls all day from concerned residents like her who believe brush fires were raging in their towns.

In a post on their Twitter page, the Holden Fire Department wrote: “We have investigated and found fires in town. At this time it is believed to be smoke from wildfires on the west coast.”

Pollution levels are likely to remain high overnight

MassDEP is advising that people in sensitive groups should reduce prolonged or heavy outdoor exertion; take more breaks and do less intense activities and follow asthma action plans and keep quick relief medicine handy.

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