After years of steady improvement in air quality, concentrations of some dangerous pollutants have increased since industrial growth picked up in 1983, the Environmental Protection Agency reported yesterday.

With tens of millions of Americans breathing ozone, carbon monoxide and industrial soot at levels higher than EPA's standards, air pollution continues to pose a "serious public health problem," the study said.

In the Washington area, concentrations of carbon monoxide from auto emissions and ozone -- a key ingredient of smog -- continued to exceed air quality standards in 1984. Levels of soot and sulfur dioxide increased slightly in 1984.

Among areas with populations exceeding 2 million, Washington ranked third in carbon monoxide pollution but rated better than most in five other dangerous air pollutants measured.

The report said that while air quality in this country improved dramatically in the past decade, progress has tapered off in recent years. In 1984, concentrations of three pollutants harmful to the respiratory system -- soot, sulfur dioxide and nitrogen dioxide -- registered small increases for the first time in years.

Carbon monoxide and lead concentrations on the average declined slightly nationwide in 1984, according to the report. Although ozone was also lower, it exceeded the EPA standard for about one-third of the population.

J. Craig Potter, EPA's assistant administrator for air and radiation programs, said that the economic upturn in 1983 was responsible for the higher levels of soot, sulfur dioxide and nitrogen -- all industrial pollutants. He predicted that the impact of industrial growth on air quality will "even out" as factories build more modern facilities.

Progress in controlling other pollutants has slowed naturally as the number of industrial and auto polluters decreases, Potter said.

"While considerable progress has been made in this country in controlling unhealthful air pollution," he told reporters, "there is still much to be done, especially in many of our urban areas, which still have violations of health standards."

Ozone has presented the most vexing problem for EPA enforcers, Potter said. The pollutant -- a chemical mixture irritating to the eyes, lungs and mucous membranes -- is the only serious contaminant that on average exceeds air quality standards nationwide.

Potter said substantial increases in auto travel and industrial expansion have neutralized EPA efforts to control ozone pollution.

Although ozone concentrations dropped in 1984, the pollutant exceeded air quality standards in 50 of the nation's 78 largest metropolitan areas, according to the report. The highest levels were recorded in southern California, the Texas Gulf Coast and the industrial Northeast.

The EPA set standards for the six most pervasive air pollutants and required states to comply by 1982. Congress extended the deadline to Dec. 31, 1987, for many areas on condition that they make reasonable progress toward compliance.

Of the 16 most populous areas, Los Angeles had the highest levels of carbon monoxide, nitrogen dioxide and ozone in 1984 -- all exceeding EPA standards, the report said.

Sulfur dioxide pollution was most serious in Pittsburgh, followed by the New York-New Jersey area.

St. Louis led in concentrations of industrial soot and sulfur dioxide, and ranked among the areas most polluted by lead, nitrogen dioxide and ozone.

Washington ranked third in carbon monoxide pollution, 11th in industrial soot, eighth in sulfur dioxide, ninth in nitrogen dioxide, 12th in ozone and 13th in lead.