Alex Baur, soon to be a senior at Cheverus High School, takes a drink at Fitzpatrick Stadium in Portland during a break from a pickup soccer game Monday. With dangerous ozone levels expected Tuesday, athletes are advised to avoid strenuous outdoor activity.

Ground-level ozone concentrations along the Maine coast are expected to reach dangerous levels Tuesday, combining with continued high heat and humidity to threaten even healthy children and adults, state and national weather officials warned.

The Maine Department of Environmental Protection issued an air quality alert Monday afternoon, predicting that ozone levels Tuesday would exceed the standard considered healthy for sensitive groups, including individuals who have respiratory diseases and healthy people who exert themselves.

It’s a problem caused by pollution that’s being made worse by the smoke from 100 large wildfires raging across the western United States, said Martha Webster, a DEP meteorologist.

“When air masses move out over the Gulf of Maine, they condense pollution into smaller layers just above the surface of the water and winds push that toward the coast,” Webster said. “Now we’re seeing smoke from out West contributing to the pollution.”

It’s the fourth air quality alert issued by the DEP this year, with two previous days exceeding healthy levels, on May 2 and July 10. Last year, Maine experienced six days when ozone exceeded healthy levels, Webster said, the last one being June 12, 2017.

At elevated ozone levels, children, healthy adults who exert themselves, and individuals who have respiratory conditions such as asthma, bronchitis or chronic obstructive pulmonary disease can experience reduced lung function and irritation. When this happens, individuals may experience shortness of breath, coughing, throat irritation or an uncomfortable chest sensation.


The DEP advised job site managers, sports coaches, elder care workers, nurses and others in supervisory positions to make sure people take precautions, such as drinking more fluids, staying out of the sun, rescheduling strenuous outdoor activities and going to air-conditioned places such as stores, restaurants, libraries or cooling centers.

The public libraries in Portland and Scarborough served as cooling centers on Monday and will do so again on Tuesday. Portland’s library will be open from 10 a.m. to 7 p.m., and Scarborough’s will be open from 10 a.m. to 8 p.m. on Tuesday. Portland’s East End Community School cafeteria will also be available as a cooling center from 10 a.m. to 4:30 p.m.

Ozone levels began building Monday afternoon near New York City and Long Island Sound, according to the DEP. Winds are expected to bring these high levels of ozone up the Atlantic Coast to Maine on Tuesday.

A front bringing clouds and showers will be building in from the northwest, but it’s not expected to reach the Maine coast until the evening hours. Before that happens, sunshine will increase ozone buildup.

Ozone is a gas composed of three oxygen atoms that is found in the Earth’s upper atmosphere, where it forms a protective barrier to the sun’s harmful ultraviolet rays, according to the U.S. Environmental Protection Agency. This beneficial layer has been damaged by man-made chemicals.

At ground level, harmful ozone is created when pollution emitted by cars, power plants, fuel refineries and many other sources reacts chemically with air in the presence of sunlight. Ozone and particle pollution are the main ingredients in smog.


Particle pollution is expected to be moderate statewide on Tuesday, along with ground-level ozone inland.

The combination of poor air quality and continued high heat and humidity will exacerbate the effects of each along the coast.

The National Weather Service in Gray has issued a heat advisory that will be in effect until 7 p.m. Tuesday. Outdoor temperatures are expected to reach the lower 90s, with humidity around 70 percent, creating heat index values in the mid-90s.

“The combination of heat and humidity will make it more difficult for the body to naturally cool itself, increasing the risk of heat stress and related conditions,” according to the weather service advisory.

The advisory recommended drinking plenty of fluids, wearing lightweight and loose-fitting clothing, staying out of the sun and seeking air-conditioned quarters. Also, it suggested checking on relatives and neighbors, especially older adults who live alone, to make sure they’re staying cool.

“People who work or exercise outside or in hot environments, and children attending summer camps or outdoor sports practices, should take extra precautions,” the weather service warned. “When possible, reschedule strenuous activities to early morning.”


Exertion in these weather conditions may lead to heat exhaustion and heatstroke. Immediately move anyone overcome by heat to a cool, shaded location and call emergency medical workers.

For those who work outdoors, the U.S. Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air-conditioned environments.

Kelley Bouchard can be contacted at 791-6328 or at:

[email protected]

Twitter: KelleyBouchard

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