Local aspects of vehicular pollution

We consider the local aspects of vehicular pollution by the use of l:10 scale models. The model automobiles were placed in a low-velocity wind tunnel to simulate a queue of slow-moving city traffic and tracer gasses were then injected into the air flow though the tail pipes fitted to two of the models. Measurements show that the exhaust gases are entrained in the wake of the vehicle from which they were emitted, and are dispersed mainly by the passage of the following car. The spatial distribution of tracer gas along and across the models suggests that the level of pollution received by a commuter in a slow-moving heavy traffic may be strongly influenced by the pollution produced from the car immediately in front.