An air quality advisory is in effect for western and central Massachusetts through Friday as smoke from massive wildfires in Canada continued to waft into the United States and reached New England on Thursday.
The state Department of Environmental Protection said the air quality had reached a level deemed “unhealthy for sensitive groups,” including those with lung or heart disease, older adults, teenagers, and children. The warnings cover Berkshire, Franklin, Hampshire, Hampden, and Worcester counties, including the cities of Springfield, Worcester, and Northampton.
Wildfire smoke from Canada entered the western and central areas of the state on Thursday and will influence particle pollution levels at least through Friday, the department said in a forecast.
“People with lung disease are at greater risk from exposure to ozone, while people with either lung disease or heart disease are at greater risk from exposure to particle pollution,” the advisory said. “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. Watch for symptoms such as coughing or shortness of breath.”
No air quality alerts have been issued for eastern Massachusetts but some smoke could be visible as it is expected to cross into the area on Friday, a Department of Environmental Protection spokesman said.
“We may see some of the smoke reach the eastern portion of the state [Friday], but air quality is expected to stay in the moderate range,” the spokesman, Edmund Coletta, said in an e-mail.
The “moderate” range means the air quality is acceptable but may be a “moderate health concern for a very small number of people,” according to the agency.
“Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors,” the advisory said.
The DEP encouraged people at risk to visit the California wildfire smoke website for information. People who may be at risk are encouraged to stay inside and limit outdoor activities. Unhealthy air can also affect pets, which should be brought inside if possible, according to the site.
West of Massachusetts, several communities in upstate New York were reporting air quality indexes in the “unhealthy” category Thursday. At this level, health effects may be felt by nearly everyone and officials encourage all to avoid spending long periods of time outdoors, according to the Department of Environmental Protection
The Canadian Interagency Forest Fire Centre reported more than 500 active fires on Wednesday. Of those, 244 were reported as being “out of control,” 165 were “under control,” and 95 were “being held,” according to the agency.
The fires have left broad swaths of the United States from Minnesota to New York shrouded in smoke, prompting officials in multiple states to warn people to stay indoors and avoid breathing the unhealthy air.
On Thursday, several cities, from Cedar Rapids in eastern Iowa to Washington, D.C., reported air quality indexes falling into the “unhealthy” and “very unhealthy” categories, according to the Environmental Protection Agency’s AirNow.gov website.
The smoke from the Canadian wildfires has impacted cities across the country since late spring, especially the Northeast and New York City, which fell under a deep, smoky haze for multiple days earlier this month.
Nick Stoico can be reached at nick.stoico@globe.com.