It's possible that the N95 masks with their electrostatic charge might manage to intercept charged molecules but my chemistry is failing me as to whether NO2 or benzene would be affected.
Correct, Covid facemask does nothing to help with gasses. Op should use extractor fan and ventilation.
Additionally: the acute dangers of gas-stoves are highly exaggerated. With proper ventilation there’s nothing to worry about.
I agree with you about the surgical masks but I'm not sure that the risks of carbon monoxide can be overstated.
There have been a number of families recently in the US that have died of CO poisoning due to the lack of CO alarms. If you have natural gas appliances, definitely keep CO alarms around the house.
A few years ago we were looking at putting in a whole house fan, and one of the risks is, if you don't have proper ventilation set up, you can pull CO into the house instead of it ventilating like it's supposed to.
There are definitely risks but you can mitigate them with CO detectors/alarms.