I don't think anyone considers that significant, insofar as it appears to me that you've simply invented numbers in an attempt to wield them the way villagers wield a cross to ward off Dracula. Any time you feel like putting a little meat on those bones, I'll be around. In the mean time, those of us who've ever felt a blast of air while standing on a subway platform will continue to wonder just what in the hell you're babbling about.
Particles only move when they have more pressure on one side than they do on the other side.
Hello, McFly? Anyone home? Open the window. Observe all that air. All that air creates air pressure outside the tube, whereas there's none inside the tube. Hence, air moves from high to low pressure, into the tube. I don't think I can do this monosyllabically, so please don't make me try.
Thus if air is moving into the tube AND moving down the tube the air mass cannot be of constant density.
As convenient as it is for you to "refute" arguments I haven't made, it's really a touch dishonest. See ya round.
I've decided to outsource your argument. Call your local HVAC people. Ask them how big a blower you need to move air through 50 feet of tube. Then ask them how big a blower you need to move it through a 300 ft tube to keep the same volume of air moving. When they tell you it will require a bigger blower, you may begin your argument, and tell them what morons they are. I'm sure they will be just as impressed with you as I am.