• airborne;
  • flour;
  • particles;
  • size

Air sampling was done in a UK bakery and a flour mill with an eight-stage cascade impactor to determine the size of airborne flour particles. The concentration of captured material was determined by a competitive inhibition radioimmunoassay. Comparison of the different sites revealed that 8.79% and 52.14% of the particles in the bakery dough-brake and roll-production areas had a diameter leqslant R: less-than-or-eq, slant6.0 μm, respectively, and 19.7% of the particles in the flour mill packing area were of this size. We conclude that in dusty areas up to 20% of the airborne flour particles are of a diameter likely to allow them to be deposited in the bronchial airways and alveoli.