Unhealthy air linked to extreme heat is expected to affect most of the Maine coast Tuesday, prompting the Maine Department of Environmental Protection to issue an air quality alert.

And with daytime temperatures across central Maine forecast to remain above 90 degrees through Thursday, the July Fourth holiday week is shaping up to be an uncomfortable blend of poor air, heat and humidity.

In a statement issued Monday, the DEP said that Tuesday’s ozone levels are expected to reach unhealthy levels for vulnerable groups of people who live along the coast from Kittery to Acadia National Park. Moderate levels of ozone are projected for interior regions of the state as well as Down East Maine.

When ozone levels are elevated, children, the elderly, healthy adults who exert themselves, and individuals suffering from a respiratory disease such as asthma, bronchitis or chronic obstructive pulmonary disease – COPD – may experience shortness of breath, coughing, throat irritation, and could feel an uncomfortable chest sensation.

The DEP recommends that people try to avoid strenuous outdoor activity during the afternoon and evening hours when ozone levels peak. Mornings are the best time to exercise.

“Instead of jogging or running in a heavily trafficked area, maybe you should walk in an area with less traffic instead,” suggested Martha Webster, an air quality meteorologist with the DEP. “It can be a matter of changing your location, your pace, or the time of day you exercise.”

“We’re not saying don’t go outdoors, just rethink what you are going to do,” Webster added.

Extreme heat kills more than 600 people in the United States every year, according to the federal Centers for Disease Control and Prevention.

To mitigate the effects of extreme heat, many Maine residents and visitors are buying air conditioners, but they are in short supply, according to Rodney Wohlford, manager of Lowe’s in Augusta.

“If you want to walk out of here with an air conditioner today, you aren’t going to be able to,” Wohlford said Monday. Lowe’s is expecting a delivery of air conditioners Monday night and every night this week from the company’s distribution center.

In the meantime, fans have been flying off the shelves at Lowe’s and Renys, a Maine-based department store chain.

“We have a good supply (of fans),” Renys co-owner Adam Reny said Monday. “We’re sending out more today and ordering more today.”

John Cannon, a meteorologist with the National Weather Service in Gray, said Monday that the next two or three days will be hot, humid and hazy.

In Portland, Tuesday’s high temperature could hit 89 degrees, but when the dew point – or humidity level – is factored in, it will feel like 94 degrees, Cannon said. The heat index for interior sections of southern Maine will make it feel like 100 degrees. The heat index is a combination of actual temperature and dew point.

The Maine Center for Disease Control and Prevention recommends that during periods of extreme heat, people should use air conditioning to cool down. If you don’t have air conditioning in your home, go to a store, library, restaurant, or cooling center.

Electric fans may provide some degree of comfort, but when the temperature is higher than the mid-90s, fans will not prevent heat-related illness, according to the Maine CDC.

The Maine CDC also recommends keeping windows and shades closed during the day on the sunny side of your home and opening them up at night to let cool air in. Taking a cool shower or bath can also help cool a person down.

It’s also recommended that people stay hydrated and avoid drinks that contain alcohol, caffeine or are sugary.

“Healthy drinks like milk and water and watered-down juice and lemonade are good,” said Dr. Michael Lambke at Redington-Fairview General Hospital in Skowhegan. “But things like Mountain Dew or Red Bull or coffee or beer are not useful for hydrating us.”

Hot cars can also be dangerous. Never leave children or pets inside a motor vehicle during periods of extreme heat, authorities caution.

Staff Writers Jessica Lowell of the Kennebec Journal and Doug Harlow of the Morning Sentinel contributed to this report.

Dennis Hoey can be contacted at 791-6365 or at:

dhoey@pressherald.com