Capturing gas fumes at the pump

Funny, some say, wrinkling up the nose, there's no gasoline smell now when you fill up in many California cities. And in Washington, D.C., too. That's because these are the only two areas so far in the United States where air- pollution-control districts have ordered the use of vapor-recovery nozzles in gas stations to help meet standards set by the federal Clean Air Act.

The new nozzles, larger, heavier, and with tank-cap collars, are connected to gas pumps by two hoses under most systems in use. The object of the new technique is to catch the air- spoiling hydrocarbon vapor within the fuel transfer system. Instead of forming polluting compounds in the atmosphere, the vapors are now forced back (under various methods) into storage tanks. There is some benefit here to the dispenser since vapor inside the tanks tends to reduce evaporation.

Los Angeles air-district officials claim the vapor-recovery systems are expected to be one of the major causes of that locale's air improvement, trapping an estimated 10 percent of the former "loose" hydrocarbons emitted by stationary sources. Of the several systems in use in California, each can cost the medium-size gas station about $15,000 for installation. Engineers testing all types of systems in use in the South Coast Air District reported captu re of about 95 percent of the vapor normally emitted.