I think it sounds wrong (to my British ear, at least), because an 'amount' is normally used to refer to a known or measurable amount; the short answer would be 'It's a weak collocation (if it's a collocation at all)'. Perhaps 'amount' just isn't countable...
To get round this he could have said something countable - 'every molecule/litre/breath/bit [depending on his audience] of air that leaves a building has to be replaced.' Or he could have stuck with 'amount' and said 'Whatever,Any amount.... has to be replaced'.
Whatever - something beginning with c (either 'collocation' or 'countability') comes into the answer!