Gasoline lead content

EPA. 1985c. Regulation of fuels and fuel additives gasoline lead content. U.S. Environmental Protection Agency. Federal Register 50 9386-9399. 

The mounting concern in the last years on the negative health effects of lead in the environment has resulted in the reduction of the gasoline lead content and the promotion of the use of lead free gasoline. 

The concept of optimum octane number assumes a car population matching the available motor gasoline quality. Reducing the permissible gasoline lead content without measures being taken to optimise the RON requirement of the car population may have two consequences ... 

It may therefore be concluded that if further restrictions on gasoline lead content are considered desirable for environmental reasons, their introduction should be phased in with the introduction of engines designed to minimise the inevitable increase in total energy consumption by having octane requirements in line with the optimum RON described in this report. 

U.S. Environmental Protection Agency, Regulation of Fuels and Fuel Additives Gasoline Lead Content, Fed. Regist. 50 [1985] 9386/99 C.A. 102 [1985] No. 208561. 

Civil aviation gasoline corresponds to the grade, 100/130 it is still called 100 LL (LL signifies Low Lead) because of its low lead content of 0.56 g/1 compared to military gasolines of the 115/145 type which can contain as much as 1.28 g/1. 

Two derivatives are used to ensure constant lead content throughout the gasoline boiling range tetraethyl- and tetramethyl lead and their mixtures in variabie proportions. 

In 1957, Ethyl Corp. announced anew antiknock compound, methylcyclopentadienyknanganese tricarbonyl [12108-13-3] (MMT). MMT is almost as effective as lead on a per gram of metal basis, but because manganese was more expensive than lead, MMT was not widely used until limits were placed on the lead content of gasoline. MMT was used in unleaded fuel between 1975 and 1978. After a large fleet test suggested that MMT could increase exhaust emissions because it interfered with catalysts and oxygen sensors, EPA banned its use in unleaded fuel in 1978. MMT is used in Canada in unleaded fuel. 

In 1982-1983, the baseline value for daily intake of lead by inhalation in a nonurban environment was estimated to be 0.5 pg/day for a 2-year-old child. The baseline value was based on an average atmospheric lead concentration of 0.1 pg/m3 and an indoor/outdoor lead concentration ratio of 0.5. In an urban environment, the indoor/outdoor ratio was assumed to be approximately 0.8 (EPA 1986a). Drastic reductions in the lead content of gasoline since 1986 have resulted in a 64% decrease in lead emissions to the atmosphere (see Section 5.4.1). 

TABLE 17. Limit of lead content of gasoline (in 1988)111, and consumption of gasoline and organolead compounds (in 1989) (modified from References 111 and 113)... 

The reduction in the lead content of gasoline and the introduction of reformulated gasoline have been very successful in reducing automobile emissions, due to changes in gasoline composition, with further improvements in fuel quality proposed for the early decades of this new millennium. These projections are accompanied by a noticeable and measurable decrease in crude oil quality, and the reformulated gasoline will help meet environmental regulations for emissions for liquid fuels but will be subject to continuous review because of the potential for environmental impact. 

Heuss, J. M., G. T. Nebel, and B. A. D Alieva. Effects of gasoline aromatic and lead content on exhaust hydrocarbon reactivity. Environ. Sci. Technol. 8 641-647,... 

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