Vehicle Emissions Reduction

In addition to reducing health risks to children, the elimination of lead from gasoline has several additional benefits. For example, the use of unleaded gasoline can save money for motorists by reducing the need for frequent replacements of spark plugs, mufflers and the automobile hardware exposed to gasoline and its combustion products. A major reason is that the lead scavengers are highly corrosive and reactive. Several surveys carried out when leaded gasoline was widely used in the United States and Canada demonstrated that motorists who used unleaded gasoline spent much less for exhaust system and ignition servicing than motorists who used leaded gasoline. As a rough rule of thumb, spark plug change intervals are roughly doubled by the use of unleaded gasoline and at least one exhaust system and exhaust silencer (muffler) replacement is eliminated. unleaded gasoline has also been linked to a cost advantage regarding carburetor servicing but this has been more difficult to quantify.

Another significant advantage associated with the use of lead-free gasoline is the lengthened oil change interval. The use of unleaded fuel has been demonstrated to significantly reduce engine rusting and ring wear and to a lesser degree sludge and varnish deposits and cam and lifter wear. Because of this, oil change intervals on cars in the United States using unleaded fuel were at least twice as long as had traditionally been the case. Intervals of 10,000 miles are not uncommon with late model cars. Increased oil change intervals cannot be attributed solely to lead removal (as is indicated by some increases in vehicles using leaded gasoline) but the lead removal appears to be a major contributing factor. This is significant not only because of the reduced cost to the motorist but also because of the oil savings over the life of the vehicle and the reduction of the potential pollution problem resulting from the disposal of used oil. Experience had shown that in many countries significant quantities of used oil are disposed of in ecologically unacceptable ways such as dumping it on the ground.