| The precise assessment of the health benefits of the phase-out of leaded gasoline is difficult to make, as there are a variety of factors to consider. Exact information is not available regarding the total number of people currently affected by lead pollution, or for the people who would benefit from the phase-out of lead in gasoline. Even "rough" figures are difficult to estimate since there are many factors influencing exposure.
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| Health Benefits of Lead Phase-out in the US | To illustrate, Table 4 presents a summary of results from a study on the impact of lead phase-out in the US during the period between 1970 and 1990. The table shows the differences in health effects when comparing scenarios with and without lead phase-out, and the substantial benefits that were achieved from the phase-out of lead in the US. Estimated for a total US population of 202 million in 1970, growing to 247 million by 1990, it is interesting to compare the health effects with the population of the SILAQ countries. In 1997, the combined population of all the SILAQ countries amounted to approximately 98 million. Even if the figures in Table 4 are conservatively reduced by two thirds (roughly in proportion with the SILAQ countries' population) the health benefits from the phase-out of lead are still very significant.
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| Comparison with SILAQ Countries | An example of a systematic study is presented in the Data Sheet and Country Assessment provided by the Czech Republic. The study examined the influence of road traffic on blood lead levels in Prague. Surprisingly, the results show neither elevated blood lead levels nor health impairments.
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| BLL Trends in Hungary | The only available set of data showing a clear link between the decline in blood lead levels and the decline of vehicle-based lead emissions can be found in the Data Sheet for Hungary, where sufficient data over a number of years has been provided. In Hungary, the phase-out of leaded gasoline has led to a noticeable reduction of airborne lead concentrations - in all surveyed Hungarian cities the lead concentration was below 0.3 µg/m3 Significantly, an average decrease in BLL of 70 percent has been observed for the period 1985-1995, as the lead contents in gasoline was reduced from 0.7 g/l to 0.15 g/l during the same period.
Similar health and environmental benefits from the phase-out of leaded gasoline can be expected in other countries, and BLL should decline in the coming years due to the programs being implemented to increase the use of unleaded gasoline. In all the SILAQ countries, the EU limit of 0.15 g/l lead in gasoline has either already been adopted or will be applied in the near future (and before the year 2000). Particularly in congested urban areas with high population densities, i.e. the capital cities such as Bucharest, Budapest, Sofia, Warsaw, etc., significant health benefits may be anticipated, but this can only be confirmed with regular case studies during the coming years. The data above shows the benefits of the phase-out policy with regard to the environment, but without further in-depth surveys, one cannot yet conclusively show the link between the policy and the related health benefits. While there are indications that at least part of the reduction in BLL has been achieved by reducing emissions from transportation sources, more research will have to be performed, especially over a longer time span.
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| Health Benefits in SILAQ Countries | Hence, systematic investigation is necessary to obtain detailed information concerning the influence of road traffic on lead concentrations in air and the BLLs over a period of time. This information should be related to the progress of the phase-out process to differentiate the impacts of mobile and stationary sources of lead emissions. It is obvious that selected residential areas should be the subject of specific case studies. In concluding, although the relationship between the phase-out of leaded gasoline and the environmental benefits is quite clear, it is very difficult to quantify. As shown in Table 1, most countries with a significant increase in the share of unleaded gasoline in the market have experienced a marked decline in vehicle-based lead emissions as well as in total lead emissions (although the latter was often also influenced by a reduction of lead emissions from stationary sources). Also, there is a downward trend in airborne lead concentration levels in those countries. Slovakia is a prime example, clearly demonstrating environmental benefits from the lead phase-out - the reduction in ambient air lead concentrations in the period 1990-1995 has averaged between 50 percent and 88 percent.
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