Measurement of total lung deposition of inhaled ultrafine particles in healthy men and

Ultrafine particles ( < 0.10 µm in diameter) are present in great number in polluted urban air, thus posing a potential health risk. In this study, the total deposition fraction (TDF) of ultrafine aerosols with a narrow size distribution (number median diameter NMD = 0.04–0.1 µm and geometric standard deviation s g = ~1.3) was measured in a group of young healthy adults ( 11 men and 11 women). TDF was obtained with 6 dif-ferent breathing patterns: tidal volume (Vt) of 500 ml at respiratory flow rates (Q) o