Use of Short-Term Genotoxic Bioassays in the Evaluation of Unregulated Automobile Emissions

摘要

Exposure to fuels and fuel additives may occur through direct exposure to uncombusted fuel or fuel additive as well as to products of fuel/fuel-additive combustion. Presence of combustion products in ambient air is the major source of human exposure to motor vehicle fuels. The levels of several products of fuel combustion in ambient air (sulfur oxides, nitrogen oxides, fuel hydrocarbons and carbon monoxide) are currently regulated under the Clean Air Act Amendments (202(a)(4)) of 1977. These amendments also specify that new vehicles shall not be certified if they generate unregulated emissions which present a potential risk to human health. The objectives of this document are to review the data from selected short-term in vitro and in vivo bioassays to (a) determine if there is evidence suggesting potential human health risk either from uncombusted emissions or from emissions of combusted motor vehicle fuels or fuel additives, (b) identify the operational variables involved in generating products of concern for human health, (c) determine the probable nature of the health effects of concern, (d) estimate the ability of short-term tests to establish human risk estimates and (e) develop a short-term bioassay program to monitor the health effects of fuel/fuel additives and unregulated combustion emissions.