<<Disclaimer: Verify this information before applying it to your situation.>> If there are particles of wheat, rye or barley floating in the air as in a bakery or an animal feed barn, etc. these particles WILL end up in the gut if they are inhaled. 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. Valerie in Tacoma * Please carefully compose your subject lines in all posts * Archives are at: Http://Listserv.icors.org/SCRIPTS/WA-ICORS.EXE?LIST=CELIAC