Service station operators in the District are stepping up their campaign to rid themselves of the elaborate "vapor recovery nozzles" that the city requires on gas pumps to cut down on air pollution.

The dealers contend that "those god-awful nozzles," as a spokesman for their trade association called them, not only drive away business because they are hard to use, but that they also do little to cut pollution because using them leads to spillage.

As a result, the dealers are now trying to enlist the support of the public. The Greater Washington/Maryland Service Station Association is supplying its 100-plus members with large, stamped post cards to hand out to customers. The cards, addressed to Mayor Marion Barry, say that the customer has bought gas in the city and found the nozzles "difficult to use."

"If you haven't tried one, you should," the cards admonish the mayor.

They then go on to offer a checklist of questions such as, "Is it more important that the District have a token and ineffectual vapor recovery program than to retain gasoline sales and tax revenues for D.C. businesses and residents?"

And for those who like the system, there is a box to check: "I fully support D.C. in requiring use of these nozzles."

The nozzles consist of a hood that covers the car's filler opening and captures vapors that would otherwise escape as gasoline is pumped into the tank. The vapors are returned to the station's underground tank through a second hose that runs parallel to the normal supply line.

Dealers complain that the nozzles are heavier than conventional ones and that many people, particularly at self-service pumps, find it hard to get the hood over the filler neck.

Also, they say, back-pressure often causes the pump to shut off when the tank is not full, and when the customer takes the hood away from the filler neck gasoline often spills out.

A first generation of the nozzles began appearing in the city in 1977, but they proved unworkable and a task force was set up to study the situation. A second generation nozzle was developed, and after an 18-month phase-in period, all stations were required to have them by last Oct. 1, according to an official at the city Department of Environmental Services.

He said that all but about 50 of the city's 215 stations met the deadline. The others were given an extra 90 days to comply. Most of these did, he said, but the DES enforcement division has found a small number "that no matter how long you give them just aren't going to put them on."

He said those cases have been referred to the corporation counsel's office.

The maximum penalty for failure to comply, according to Tony Rachal, an attorney for the dealers association, is $5,000 a day in fines and/or 90 days in jail.

Officials at the Department of Environmental Services and staff members at the City Council agree that the nozzles are here to stay. They are integral parts of the city's plan for cleaning up the air, and that plan, in turn, has been built into the Metropolitan Area Council of Governments' plans for the region, these officials say.

Any retreat by the District in this area would leave it open to future federal sanctions, such as loss of highway or sewer funds, unless the city were able to eliminate a comparable amount of air pollution from other sources.

The problem is, however, that the city has no other significant pollution sources. "Pollution here is cars," said one council staffer. When it was drawing up its plan, "the city looked at what it had and what it had was cars. There really isn't anything else--we don't have any steel mills or coal mines," he said.

Nevertheless, many of the dealers' complaints are "legitimate," the staff member said, suggesting D.C. might consider some form of tax credits or a reduction in the sales tax on gasoline--currently three cents greater than the suburbs'--to help dealers bear the burden of helping clean up the air.

He also admitted that there is some question about the effectiveness of the nozzles. He noted that the Environmental Protection Agency has no "control technology guidelines" for these types of devices. "It works in an experimental situation, but not if you don't use it right," he said.

He said members of the council recognize the competitive problem District dealers face, and suggested that DES could do more to educate the public on the nozzles. The public supports pollution control, he said, and if they understand the purpose of the nozzles and how to use them, there might be less resistance. He said Virginia and Maryland are studying the nozzles and will make a decision on them by 1985.

In the meantime, however, dealers say they are being badly hurt. Tim Sawyer, who runs three BP stations--two in the District and one in Maryland--says sales at his two District stations are down sharply. Before the nozzles came in, his station at New Hampshire and Eastern Avenue was pumping 3,200 gallons a day; since the nozzles were installed, the figure has fallen to 2,000 a day.

He said that women, particularly, have trouble managing the nozzles, and some business executives are driven off by the fear of spilling gasoline on their clothes.

He also said three of the 10 pumps at that station have the conventional "Maryland nozzles," which account for 60 percent of his sales. He is allowed to have one "Maryland nozzle" for each type of gasoline for vehicles that can't be filled with the vapor recovery type, "but where would I be if they took those away from me?"

Rachal said the dealers want a regional approach, with abatement requirements--whatever they are--applied to all dealers, not just those in one jurisdiction. "It's all one air basin, and if people buy gas in the suburbs where there are no controls, there's no gain," he said.