Individual and population exposures to gasoline.

Area of Science:

• Environmental Chemistry
• Occupational Health
• Exposure Science

Background:

• Gasoline is a complex mixture of hydrocarbons, alcohols, ethers, and additives, with variable composition.
• Exposure to gasoline constituents can occur during refueling and through vehicular emissions (evaporative and tailpipe).
• Defining specific chemical exposures is essential due to the variable nature of gasoline.

Purpose of the Study:

• To analyze the composition of gasoline and its associated exposures.
• To quantify exposure levels during self-service refueling.
• To characterize emissions from vehicles, including evaporative and tailpipe releases.

Main Methods:

• Analysis of gasoline composition and constituent proportions.
• Measurement of airborne hydrocarbon concentrations during refueling.
• Quantification of evaporative and tailpipe emissions from vehicles.

Main Results:

• Refueling exposes an estimated 111 million people to gasoline constituents, with total hydrocarbons typically at 20-200 ppmV.
• Liquid gasoline loss during refueling averages 0.14-0.23 g per gallon.
• Vehicle emissions include total hydrocarbons (0.2-2.8 g/mile for running losses, 0.3-1.0 g/mile for tailpipe) and specific compounds like benzene.

Conclusions:

• Accurate exposure assessments require defining exposures to individual chemicals or chemical groups due to gasoline's variable composition.
• Refueling and vehicle emissions represent significant pathways for human exposure to gasoline constituents.
• Further quantification of skin exposure from spills and detailed analysis of emission components are warranted.