Formaldehyde and Methyl Nitrite Levels in a Garage During the Cold Start-Up of a Methanol Fueled Vehicle.

Abstract

A three-dimensional computer simulation was performed to determine the formaldehyde (HCHO) and methyl nitrite (CH3ONO) levels inside a small garage during the cold start-up of a methanol fueled vehicle (MFV). The garage size was appropriate for one MFV. Two types of garage were considered in order to quantify the ventilation effect. The total amount of pollutants was independent of the ventilation until 70 s after engine start-up, because the pollutants remained concentrated directly behind the vehicle. After 180 s, the pollutant levels in the ventilated model were reduced to half that in the no-ventilated model. However, under such small garage condition, even with one ventilator, at a point 1 m behind the MFV and 1.5 m high, the HCHO concentration reached 9.2 ppm. To reduce the HCHO level to below 5 ppm, the HCHO peak concentration in the emission should be reduced to 0.5 times the present concentration. Although the harmful effects of CH3ONO have not yet been investigated in detail, they should be considered, particularly during cold start-up of MFV in a closed garage.