Carbon Monoxide

Like I said earlier, climb into your trunk and have someone shine a bright light along the seal,.......................... carbon monoxide doesn't need a large gap because the car creates a vacuum inside the passenger compartment when you're driving down the road. This low pressure causes the passenger compartment to "SUCK" the outside air into the car.

EXACTLY what I was trying to get across earlier, and doesn't only apply to the rear of the car