§ 41. Mr. Russellasked the Minister of Transport and Civil Aviation why it is considered better for exhaust fumes from motor vehicles to be emitted near the ground rather than at roof level.
§ Mr. NugentExhaust fumes are heavier than air. In densely trafficked streets if the fumes were emitted at roof level they would fall and enter the windows of other vehicles, especially stationary ones, and 5W nearby buildings as well. On the other hand, emission near the ground avoids these ill effects.