Gasoline lead levels

Fig. 3 shows the effect on energy consumption of reducing the lead content of gasoline whilst maintaining constant gasoline consumption/production (i.e. 1,000 tons). This corresponds to a situation where permissible gasoline lead levels are restricted without any measures to reduce the octane requirements of the vehicle population. The curves for 0.60, 0.40 and 0.15 Pb/L are taken from the original CONCAWE report (2). If the lead is not added to the latter case, than the curve will be displaced to the left by 3 RON. 

Studies carried out by the Center for Disease Control and Prevention (CDC) show that the levels of lead in the blood of U.S. children have been getting lower and lower. This is because lead is banned from gasoline, residential paint, and solder that is used for food cans and water pipes. Still, about 900,000 U.S. children between the ages of 1 and 5 years are believed to have blood lead levels equal or greater than 10 ig/dL, the CDC level of concern. 

Information on occupational exposure to lead is obtained primarily from the National Occupational Exposure Survey (NOES) and industry surveys of workers. While occupational exposure is widespread, environmental monitoring data on levels of exposure in many occupations are not available. OSHA has established a permissible exposure limit (PEL) for lead of 50 pg/m3 for workplace air (OSHA 1991). NIOSH has estimated that more than 1 million American workers were occupationally exposed to inorganic lead in more than 100 occupations (NIOSH 1977a, 1978a). According to NOES, conducted by NIOSH between 1980 and 1983, an estimated 25,169 employees were exposed to tetraethyl lead (not used in gasoline since December 31, 1995) approximately 57,000 employees were exposed to various lead oxides mostly in non-ferrous foundries, lead smelters, and battery plants 3,902 employees were exposed to lead chloride and 576,579 employees were exposed to some other form of lead in the workplace in 1980 (NIOSH 1990). Workers who operate and maintain solid waste incinerators are also exposed to air lead levels as high as 2,500 pg/m3 (Malkin 1992). 

Lynam DR, Pfeifer GD. 1988. Effects of decreasing lead exposures from gasoline and other sources on blood lead levels in man. Third Chemical Congress of North America held at the 195th American Chemical Society Meeting, Toronto, Ontario, Canada, June 5-10, 1988. Abstr Pap Chem Congr North Am 401-404. 

Laidlaw Filippelli (2008), Laidlaw et al. (2005), and Filippelli et al. (2005) have demonstrated that seasonal variations in children s blood lead levels In Syracuse, Indianapolis and New Orleans could be predicted using soil moisture and atmospheric variables suggesting that resuspension of urban soils contaminated by past use of leaded gasoline and paint were causally related to seasonal variations in blood lead. These papers concluded that urban lead contaminated soil was being re-suspended when soils were dry in the summer and autumn when... 

The decline in acceptable childhood blood levels was a function of research and improved control of lead contamination, such as the removal of lead from gasoline. A blood lead level of 10 lg/dl does not represent a safe level, only one where it is prudent to take action to reduce exposure. But it must be noted that a level of 10 (Xg/dl is considered an action level and does not provide any margin of safety for a child s developing nervous system. Currently, there appears to be no safe level of lead exposure for the developing child. 

Sweden s crusade against the use of certain heavy metals provides a recent example of a blatant failure to observe the EU Commission s first requirement of proportionality of measures to achieve the appropriate level of protection. Many of the proposed restrictions cannot be expected to improve human health at all, or to have significant beneficial effects on the environment. During the last decades, lead levels in the blood in the Swedish population, including children, have steadily decreased, mainly as a result of the phasing out of leaded gasoline,41 and they are now similar to... 

Emission studies show that lead is only a small part of the automotive pollution problem. Prior to control, hydrocarbon emissions were more than 40 times and the oxides of nitrogen emissions more than 15 times the emission of the lead compounds. Obviously, however, legislation will result in the eventual elimination of lead from gasoline. The removal of lead, besides eliminating a possible toxic pollutant, simplifies the problem of handling other automotive exhaust pollutants in that catalytic exhaust chambers perform much better in the absence of lead contaminant. All emission standards become particularly severe in 1975 and 1980. The particulate standards are equivalent to 1 gram Pb/gal in 1975 and 0.3 gram Pb/gal in 1980. Since the particulates include all solid materials, tolerable lead levels will be less than indicated above. 

A compilation of available lead retention data is given in Table III, indicating only the most important conditions of a given test, where the information was available. With the exception of the work with pelleted vanadia catalysts (14), all the data pertain to lead levels in the range of 0.01-0.5 g Pb/gal, which was the range of interest in the years from 1972 to 1975, when the limits for contaminant levels in gasoline compatible with catalyst operation were actively considered. The data in the table cover an extremely wide set of conditions and include laboratory simulation, dynamometer, and vehicle fleet tests. Nevertheless, with a few exceptions, the lead retention falls within a relatively narrow band between 13 and 30%. 

The relative contribution of mobile source emissions to atmospheric lead levels over the next decade is expected to decrease slightly for two reasons (1) the Federal government s imposition of a phasedown of lead content in gasoline, as called for in regulations promulgated in September 1976 (43) and (2) the incompatibility of leaded gasoline and the catalytic converter introduced in late 1974 for control of regulated (HC, CO, NO,) pollutants (44,45). 

It is apparent that these "fingerprint techniques relating particle sizes as well as concentration data to source components need further refining. However, it should be possible eventually to identify the origin of airborne particles provided suflBcient chemical data become available. Recently, lead isotopic ratios have been used to estimate the contribution of blood lead levels originating from gasoline combustion. Perhaps this approach can be further refined to better characterize the sources of other airborne metals. 

Control and reduction of ambient air pollutants in the United States has met with varying degrees of success. Unleaded gasoline now accounts for 99% of all gasoline sales. This change has virtually eliminated mobile sources as emitters of lead and reduced ambient lead levels by more than 75%. Likewise, stationary point sources of lead emissions, primarily industrial smelters, have dropped by more than 90% over the past three decades, although significant... 

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