Originally Posted by Franc Rauscher

Air velocity is not pressure. The air volicity to which you reffered is "in the nozzle" It has no reason to have an increase in velocity unless there is a difference in pressure between the one end of the nozzle and the other.

If a pipe is forced thru a gas and the gas in the nozzle has a velocity increase, it must be the result of different air pressures in the leading end of the pipe verses the exiting end.

The venturi diagram above illustrates this fluidic function.
roadster with a stick