June 25, 2018
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Heat, humidity, winds combine to produce bad air, DEP says

By Tom Groening, BDN Staff

BELFAST, Maine — Unhealthy air quality is expected to flow over Maine’s coast from Kittery to Bar Harbor on Friday and Saturday, putting the elderly, children and those with heart or lung disease at risk.

The Maine Department of Environmental Protection has issued a warning about the air quality, which it attributes to a combination of high heat, high humidity and a change in wind direction.

Tom Downs, DEP’s chief meteorologist said Thursday that for much of the recent weeks of warm weather, the winds have been from the west-northwest. As they swing to the southwest, the winds will carry the nitrous-oxide pollution from power plants and factories in the major cities in the central part of the country to Maine, he said.

The Maine Emergency Management Agency’s weather forecasts call for temperatures in the high 80s in coastal regions on Friday and Saturday.

Those in the warning categories are urged to minimize outdoor activity and to stay inside and keep cool, Downs said. Everyone exposed to the heat and humidity is encouraged to drink plenty of fluids.

Coastal Maine often experiences such poor air quality on hot, humid days in the summer, and this stretch of weather is not expected to produce especially bad conditions, he said.

Hot, humid air can carry more particulate matter, Downs said. When particles measuring 2.5 microns and smaller are detected, those in the at-risk categories are warned. Particles of that size “will go deep into your lungs,” Downs said.

Longer stretches of hot, humid weather with the accompanying southwesterly winds could warrant warnings for more people.

“We’re not expecting real high numbers,” in terms of heat and humidity, he said, so a more dire warning is not being issued.

Still, everyone is urged to avoid strenuous activity, such as running along busy roads and during the middle of the day. Closing windows and circulating indoor air with a fan or air conditioner also are recommended by DEP.

This is Maine’s first air alert of the year. The National Weather Service had issued a heat advisory that had nothing to do with air quality on June 19 when temperatures in the mid- to upper-90s combined with high humidity in the southern part of the state to make temperatures feel more between 100 and 103. That advisory warned Mainers at the time that prolonged exposure to such heat and humidity could cause serious health problems.

The first air quality warning of last year came on June 8. Similar alerts are being issued for Friday, July 13, for parts of New Hampshire, Massachusetts, Connecticut, New Jersey and New York, according to DEP.

Though the warning covers Friday and Saturday, Downs said the air mass moving into Maine then is expected to be here through Wednesday, potentially causing more concerns.

Along the immediate coast, the heightened presence of vehicle exhaust from tourist traffic coupled with sunny, hot days creates ground-level ozone, also known as smog. The heat causes one oxygen molecule to break away from O2 and combine with the single oxygen molecule associated with carbon monoxide, forming O3, a gas that threatens health, Downs said.

Daily air quality forecasts are available on DEP’s website, www.maine.gov/dep (click on “Today’s Air Quality Forecast”) and via a toll-free hotline which can be accessed by dialing 800-223-1196.

Forecasts can also be accessed each day on the DEP Air Bureau’s four Twitter accounts, one for each region where air quality alerts have been issued in recent years including midcoast (@meair_acadia), eastern interior (@meair_bangor), western interior (@meair_lewiston) and the southwest coast (@meair_portland).

Weather forecasts are available at www.weather.gov/gray or by calling 688-3210.

More information on staying healthy in the heat is available at www.maine.gov/dhhs/mecdc/environmental-health/heat.

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