Most of the focus here seems to be on the issue of oil fume in the air conditioning and pressurization system. Which is understandable given the carcinogenic properties of turbine oil.
My worst experiences with fumes/vapor/smells have been after deicing. And it seems to have worsened in the last decade. I don't know if that is due to me being older but I suggest that it may be more due to the fact that we use a lot more type 4 fluid these days. It used to be that we were deiced and that was it. Now we have type 1 and type 4 fluid put on during the same process. I know I am very careful about having the packs off and the ditching switch on during deice but you have to turn the packs back on afterwards and that stuff does drip and spread and finds its way back into the A/C system.
I would like to see more attention given to the mix of fluids we are deiced with. All I can do now is run the packs on high and put on my mask if it gets too bad. It does go away after 30 minutes or so but I have received an airplane later in the day that had a deice smell and I knew it had been at least 7 hours since it had been deiced.