The cool, dry air carrying relief from the heat wave slowed in its drift toward the Washington area yesterday, and the high temperature and humidity conspired again to extend both the discomfort and the air pollution alert.

Yesterday's high temperature was 91 degrees, lower than that of several previous days but still the 13th day in the last 14 that the temperature has reached 90 degrees or above.

The air quality index registered 125 at 3 p.m., a "very hazardous" reading and the Metropolitan Washington Council of Governments extended its air pollution alert for 24 hours. It was the fifth day in a row an air pollution alert had been called.

The National Weather Service said relief in the form of drier, cooler Canadian air mass did not reach the Washington area yesterday afternoon as scheduled and was still centered over the Great Lakes.

A weather service spokesman predicted the Canadian air mass should reach the Washington area by early this morning.

Yesterday, however, the Maryland Health Department also extended its air pollution alert for the city of Baltimore and for Montgomery and Prince George's counties despite the brief thundershowers that swept through the Washington area in the morning.

Although temperatures were lower than the day before, the weather was still an easy target for complaints from Washington area residents.

At the Tidal Basin, 19-year-old Patsy Torrecarion gave the weather as her reason for quitting her summer job as a cashier for rental paddle boats.

"With the storms and the humid weather keeping people away, I just can't get that many hours here and I'm not making any money," she said.

A few miles away, 30-year-old Jo Ann Davis of SE Washington strolled across New York Avenue balancing a slice of watermelon in her hand.

"The weather is smoking, but it is cooler today than yesterday," she told a reporter.

In Silver Spring, Arthur Cotts, an engineer, sought refuge in his air conditioned home after spending the morning outside. "I'm used to hot weather, but this is terrible," he said.

While area residents again sought relief from the sweltering heat, residents in Prince George's and Montgomery counties began easing off the restrictions on water usage prompted by the recent water crisis. Although county authorities and the Washington Suburban Sanitary Commission are still urging some voluntary conservation in water usage by residents, reopened swimming pools and other amenities brought favorable reactions from residents interviewed yesterday.

In Silver Spring, 20-year-old Mike Price said his family was still using paper plates, "but we are flushing the toilet as much as we have to."