Methanol exposure from an M85 fueled vehicle parked in an attached garage

A mixture of 85% methanol and 15% gasoline (M85) has been proposed as an alternative fuel for gasoline in CO and ozone non attainment areas. Its use will potentially increase methanol inhalation exposure indoors resulting from evaporation of methanol vapor from methanol fueled vehicles parked in residential garages. This study assessed the indoor air concentrations of methanol and selected Volatile Organic Compounds (VOC) resulting from evaporative emissions from a car fueled with M85 and parked in a residential garage to evaluate potential inhalation exposures to the general population.; The indoor air concentrations of methanol, benzene and toluene were measured in a residential home with an attached garage. The affect of vehicle emission control device (charcoal canister hose connection), house HVAC (heating, ventilation air conditioning) fan, ambient air temperature, garage temperature, fuel tank temperature and wind speed were examined. The disconnection of the charcoal canister hose, which simulates a malfunctioning or spent evaporative emission control device resulted in elevated benzene, toluene and methanol concentrations in the garage and attached home. Higher fuel tank temperatures resulted in higher air concentrations for benzene and toluene in the garage, but not for methanol. The concentrations of all compounds in the garage and the concentrations of benzene and toluene in the adjacent room were lower when HVAC fan was on than when off, while the concentrations of all three compounds in the remainder of the house were higher, though these differences were not statistically significant.; The Monte Carlo technique was used to evaluate potential dose and risk distributions by combining the concentration, time activity pattern, inhalation rate, life expectancy and body weight. The risk associated with exposure to methanol, benzene and toluene were the highest for children between ages of one to four. The total daily dose were 84.1 ug/kg, 2.71 ug/kg and 39.4 ug/kg for methanol, benzene and toluene, respectively. The risk from methanol exposure in the highest exposed group (younger children) were less than 1 implying that the estimated methanol indoor air exposures present no elevated health risks to the general population. Insufficient toxicological data exist to evaluate health risk to sensitive populations such as pregnant women.; A multi-zonal mass balance indoor air model was employed to predict the air movement between rooms and the temporal methanol contaminant concentration gradients. This model showed that there is infiltration from the source room (garage) to the adjacent room and further to the rest of the house. The temporal trend of the model output matched the measured data in the adjacent room, the remainder of the house and the first hour simulation in the garage. Variations in the source term had the greatest effect on the results. The infiltration concentration of evaporative emission was greater in the adjacent room than in the remainder of the house.