I was idly going through slashdot on Friday, where I came across a link to a story on the Globe and Mail. Apparently, the Canadian Transportation Agency told Air Canada to provide a nut-free buffer zone in their airplanes. Air Canada had already stopped serving peanuts on-board, but they were still serving cashews nuts. That move was prompted by the complaint of a passenger that was severely allergic to nuts.
Interestingly, the Agency considered a severe food allergy to be equivalent to a disability that the air carrier should take into account in the service they offer.
I imagine, the easiest way to comply with that decision is to stop serving nuts altogether. Isolating a part of the plane and making it allergen-free is technically possible but it won't come cheap (think of air filters or at least air-curtains, special floor mats, regular surface cleaning, control on who and what enters that zone, zone autonomy - e.g., restrooms, and a procedure to control those things).
Allergens in food have been receiving increasing attention lately. In the EU there is concise legislation in place that requires foodstuffs to identify on the label any allergens that are contained as ingredients (either as main ingredients or as carry over substances from one of the main ingredients or from one of the treatments the foodstuff or one of its ingredients was subjected to) as well as any allergens that are likely to be present in traces (e.g., due to contamination during the production process). The list of allergens is regularly reviewed and revised. When needed, EFSA also looks into cases of allergens used as technological aids in food processing and tries to assess the levels that can survive until the final product and estimate the corresponding risk.
However, in my understanding, so far, food allergens have not been treated as a hazard with an environmental dimension. Personally, I am unaware of the potential effect of food allergens on people with severe allergy, when the contact is made through the skin (or the lungs, in case a food allergen can somehow be found on fine dust). I would imagine that brief skin contact could not easily lead to adverse reactions; but, then again, I am no expert on allergies and, thus, I might be very wrong on my hypothesis.
While I acknowledge the risks, the inconvenience and all the negative effects that allergies have on the quality of life of the people affected, I tend to believe that in severe cases, the person affected should also take his/ her condition into consideration. What exactly that may mean, really depends on the case and their doctor's advice. It could mean avoiding certain places or wearing long sleeves and gloves or a mask (i.e., means to avoid coming in contact with the allergen), carrying cortisone or antihistamine medication or even shots of epinephrine (i.e., means to fight the allergic reaction), etc.
After all, it makes sense to me that one should take reasonable care of oneself!