Hi Bluebutterfly,
Yes … each manufacturer uses a different compounding formula (that is proprietary) for their latex whether it is poured on a belt or in a mold and it’s certainly possible that someone could be sensitive or reacts to something that a particular manufacturer is using. Most manufacturers that have worked with latex for years will also tell you that some batches of latex (or any natural material) can have a stronger smell than others and this is particularly true with natural latex (or any natural material). It’s also true that some people are more sensitive than others to certain smells than others and the odor itself can be offensive or even cause some reaction even if it’s not harmful to most people. The smell of certain foods for example (cooked cabbage is an example for me) can make me sick to my stomach while for others it can be appetizing. I’ve seen examples where one person can react to a smell that others don’t even smell at all because for some reason they are more sensitive to that particular type of smell.
My own guideline is that personal experience “trumps” everything else no matter how may others may be sensitive to the same thing. Some people will still be able to smell the smell of the latex after many months even though it has diminished to levels that others won’t notice. If you put your nose close to a bare latex layer and inhale it can still have some smell remaining even a year or more after it was manufactured.
It would work for containing the smell IMO yes but it may not be comfortable for most people because the polyethylene would not be breathable and would tend to retain heat and would interfere with the feel and performance of the latex. I don’t think it would have any significant effect on the durability of the latex except perhaps to some small degree related to more rapid heat aging of the latex (this is an educated guess and not based on any testing I know of).
I should also mention for the sake of completeness that when latex is shipped on untreated wooden pallets that it would need to be fumigated before entering the country (because of the wood) and while this would be very rare and I can’t imagine a manufacturer that would do this, it’s possible that some latex shipments would be subject to fumigation (see post #2 here).
Phoenix