<<Disclaimer: Verify this information before applying it to your situation.>> Dear List, A week or so ago, I wrote to say that my experience suggests that the problem with air-borne gluten is that it lands on one's lips and is then inadvertently licked off and swallowed. Several listers responded with useful addenda and corrections: 1. That is why I stay out of obvious places where flour is floating in the air i.e. pizza parlors, bakeries, pancake houses, Long John Silver's. I understand that flour can hang in the air for many, many hours. 2. It can land on the food, too! 3. Don't forget that when you inhale, inhaled particles are also deposited along the back of the nose/throat in the naso and oropharynx, which are then also swallowed. 4. The inside of the nose & throat is covered with mucous & tiny hairs called celia. The mucous & celia trap particles & brush them to the back of the throat where they are swallowed. This process is controlled by involuntary reflexes and cannot be prevented. This is part of our body's natural defense system. The system is designed to protect us from invasion of bacteria & viruses by trapping & sending these pathogens to the stomach where they can be destroyed by stomach acid & digestion. Unfortunately, gluten is not destroyed by stomach acid & normal digestion. Flour & grain particles are quite large compared to bacteria & virusus so just about any good fitting mask should provide adequate protection from these particles entering the nasal passages. However finding a good fitting mask that effectively seals out unfiltered air can be difficult. The nose hairs also act as a barrier to catch particles before they can be pushed back, but of course they don't catch everything. It there is grain dust in the air, it has a good chance of getting to the throat. Current medical belief holds that, irrespective of symptoms, the inflammatory reaction to gluten arises solely in the gut, or (somewhat controversial, and in any case hardly universal) the Purkinje cells of the cerebellar cortex. It is my understanding that at present, there is no physiological explanation for apparent reactions to gluten contacted outside the digestive tract. Bottom line: air-borne particles can land on anything and have myriad options for access to the gut. And, as we know, it doesn't take much to trigger the inflammatory reaction. regards, Mary B. NYC -- *Support summarization of posts, reply to the SENDER not the CELIAC List* Archives are at: Http://Listserv.icors.org/SCRIPTS/WA-ICORS.EXE?LIST=CELIAC