The problem of total loss oil consumption, however, remains a cause of high hydrocarbon emissions.

In the late 1980's, the group required oil companies to make changes in gasoline to reduce hydrocarbon emissions.

This leads to high carbon monoxide and hydrocarbon emissions.

Unburned hydrocarbon emissions have never reached concentrations that could support a "skyfire."

The oil companies agreed to reduce their hydrocarbon emissions sufficiently to allow the car plant to be built.

Almost half of the hydrocarbon emissions come from cars and trucks.

But auto makers worry about the increase in hydrocarbon emissions.

Over the next 13 years, the regulations set out to achieve a 70 per cent cut in hydrocarbon emissions.

Air pollution also is made worse by increases in natural hydrocarbon emissions during warm and hot weather.

Until recently, the restrictions have been more about curbing noise than cutting hydrocarbon emissions.