There is a sullen haze over the land. The mailman drags down Main Street in Upper Marlboro in a T-shirt and shorts. In Arlington, county worker Mary Mannix scoots from one air-conditioned spot to another.

August: The least glamorous month. Dog Days: The mongrel of the year.

"The air's so thick, you think you need to claw through it," said Mary Alice Ruslander, a secretary in the state's attorney's office in Upper Marlboro.

Yesterday, the official thermometer at National Airport read 82 degrees at 9 a.m.; 94 by noon; and by 4 p.m., 98 degrees, tying the record for the date set in 1980. While the normal mean temperature is 1.3 degrees higher in July than in August, the humidity combined with yesterday's record high temperature for the year made it especially uncomfortable. And there is no relief in sight through the weekend.

Summer, it seems, has finally lost its glitz. The steering wheel is a ring of fire; the sidewalk, a bed of coals. The area is experiencing classic Dog Days weather -- steamy, sticky, unyielding -- and classic Dog Days attitudes. People would rather not be bothered.

"It's too hot to work, too hot to think," said Upper Marlboro attorney Jeffrey Wennar. "It's almost too hot to wear anything."

Potomac Electric Power Co. reported an all-time peak use of about 4,700 megawatts yesterday afternoon, exceeding the previous record use of 4,490 megawatts on June 13, 1984. Pepco spokesman Tom Welle said the company had no problems meeting the demand for power and has been able to sell some of its surplus to other utilities.

By late morning, the Metropolitan Washington Council of Governments reported that ozone in the air had reached unhealthy levels. Ozone is formed when high energy radiation from the sun interacts with oxygen, making the air thick and difficult to breathe. People with heart and lung ailments are advised to remain indoors, and the general public is encouraged to reduce strenuous activities, said COG environmental planner Rob Kaufmann.

There were some reports of people passing out from the heat. Three patients were treated and released at Prince George's General Hospital yesterday afternoon; Suburban Hospital in Bethesda treated and released two persons suffering from heat exhaustion.

As a result of the ozone levels, the District, for the first time this summer, closed its two automobile safety and emissions inspections stations at noon yesterday, two hours early. About 1,200 vehicles normally are inspected each day.

"We've got such a concentrated situation here with automobiles and exhaust, and the afternoon is the hottest part of the day," said Larry Greenberg, chief of the D.C. Bureau of Motor Vehicle Services. "We believed it was in the best interests of the citizens and our employes to close early." Decisions on when to close today and on successive hot days will be made daily, he said.

What gives Dog Days their name is the Dog Star, Sirius, the brightest star in the constellation Canis Major. Sirius rises and sets with the sun during the hot humid days of late July and August.

What is giving area residents such a broiling week is a Bermuda high sitting over the eastern United States. "Everything is stagnant," said National Weather Service specialist Joseph Cefaratti. "It's hard to say how long it will keep sitting there."

Similar weather is expected through the weekend at least, Cefaratti said. That means daytime highs in the 90s, nightly lows in the low to mid 70s, and a good chance of afternoon thundershowers.

Not exactly heartening news, but there is a flip side to the discomfort of the weather. Nobody really expects much.

"There is a more relaxed attitude," said Ruslander. "Everybody is on vacation anyway, so why bother? After Labor Day, though, there will be a distinct shift in attitudes. Then, it'll be back to business."