Fullwings beat me to the maths, thank you. So some numbers. Normal packaging is based on a sublimation rate of 2%/hr, this allows our 75s 2T of dry ice on the main deck. Our current enhanced packaging is based on 1%/hr, allowing 4T on the main deck. This new packaging allows 13T. Alongside this there are rules about other freight nearby, primarily animals. (All figures rounded).
Be assured, aircrew always have 100% O2 available.
There is no good reason to have a flight as vaccine only. You can get loads of doses in a very small space and I believe our first vaccine flights are mixed cargo. For us it’s just another pallet or bin of freight to be packed in a certain way.
As said before there are no plans for CO2 monitors, though I am happy to ask the question on Thursday.
With the exception of a main cargo deck fire there are no QRH drills requiring decompression. If I felt that my performance was impaired due CO2, smoke and fumes would be the place to start.
The biggest danger with CO2 would be Fullwings handling it with the ice cream and getting a cold burn. Ps Catering dry ice doesn’t count towards the totals above.