Here's an excuse not to run outside today: It may be bad for you.
Unhealthy hot air will settle over much of New England - including virtually all of Massachusetts - today and tomorrow and environment officials are telling people to avoid strenuous outdoor activities.
A smog-polluting power plant
People should try to turn up temperatures on air-conditioners, carpool and avoid using machines such as lawnmowers. That's because electricity-supplying power plants, cars and gas-powered engines emit smog-making pollution.
Still, the humid, stiffling weather - already at 80 degrees at 8 a.m. - is expected to push electricity demand to near-record levels.
Smog, or ground-level ozone, can aggravate asthma, cause breathing problems, and make people more susceptible to respiratory infections.
When ozone levels are high, people should avoid strenuous activity - especially sensitive populations such as children and adults with respiratory problems, environmental officials say.
The unhealthy air is predicted in Coastal Maine from Kittery to Acadia National Park and inland from the Maine coast to Lewiston-Auburn, Augusta and Bangor, southern New Hampshire and all of Massachusetts except the southeastern sections.
New England has already experienced 16 days with high ozone levels and more are expected: The U.S. Environmental Protection Agency recently lowered the air quality health standard.
EPA officials recommend the following:
* Use public transportation, car pools or try to combine trips.
* Refuel cars at night to reduce gasoline vapors getting into the air during the daytime when the sun can cook the vapors and form ozone.
* Avoid the use of small gas-powered engines such as lawn mowers, chain saws, and leaf blowers.
About the green blog
Helping Boston live a greener, more environmentally friendly life.
Christopher Reidy covers business for the Globe.
Doug Struck covers environmental issues from Boston.
Glenn Yoder produces Boston.com's Lifestyle pages.
Eric Bauer is site architect of Boston.com.
Bennie DiNardo is the Boston Globe's deputy managing editor/multimedia.
Dara Olmsted is a local sustainability professional focusing on green living.