They also call the stuff "waft"

Ziggy provides us with an inadvertent look at a horrible future - one where pollution, lethargy and decay have turned the world into a wasteland and the landscape is dotted with posh Oxygen Dens - hovels of iniquity where citizens gather together to "catch a breeze", as they call it, breathing pure, unfiltered 02 instead of the gaseous nutrition cocktail cooked up by the government. Cheaper still are the guys on the street asking "Buddy - want a whiff?" and holding out breathing masks, but you don't know where those ventilators have been.