All pole holes that are not essential should be permanently sealed. Active pole holes should have flexible covers with air tight seals. An alternative is to install air tight booths around poles. Ventilation systems should be installed to control vehicle exhaust. The two types of ventilation systems which may be used are dilution and local.
Local exhaust is preferable because it removes the diesel exhaust at the source.
Dilution Ventilation Hot exhaust emissions rise, therefore, exhaust fans should be located near the ceiling and exhausted outside. The volume of exhaust emissions generated is dependent on the number of trucks in operation in the firehouse and the horsepower of the trucks. Make-up air must be supplied to replace exhausted air. The exhaust opening should be situated to prevent re-entry of exhaust through windows or fresh air intakes. An exhaust filter hose system should be connected to the tail pipe of the truck.