Olom, great attitude!
When this book was written, the environment was not a big issue yet.
By now, most of humanity has learned not to poop in your own water well. Some parts of the world are still catching up.
Most sustances are only harmfull at certain concentrations, others can accumulate over time in your body or in nature and cause serious damage that way.
It usually comes down to emission limits. So much micro gram of a substance per cubic meter of expelled air. Or total amount per hour.
No economic way to measure that for the small guy.
Prevention is the biggest factor. No need to scrub fumes if they are not created
(in large quantities). So either slow reactions in semi closed vessels with low emissions or big and fast reactions which will require huge scrubbing systems.
So don't create a lot of fumes, and if you do, don't let them escape to open air without scrubbing them first. Have the fume hood there to get the traces of gasses and unintentional releases or accidents vented away from you.
But very good to hear you are aware of this and you want to limit the gases expelled.