Okay - i admit my previous statement was wrong, and this mixture does indeed enter the atmosphere.
It does however break-down relatively quickly by both sunlight and microorganisms in earth - as it's half-life is only 22-days. So as far as chemicals that impact the environment, acetone is certainly far from the worst.
Back to the original question -
is anyone else besides myself and the 2nd poster bothered when they receive new boards that contain all of the Flux from the assembly process?