When you're running in a pack of cars in over two hundred miles an hour, it's unsettling for the drivers and for the cars. The drivers refer to it as dirty air. In a way you can see dirty areas through computational fluid dynamics (CFD). That's computer modeling that will show the airflow across the car. The model was provided by dragon racing and the simulations done by TotalSim at Ohio. The results are dramatic and anyone can certainly see why it is called Dirty Air.