Fig. 12
Total dissolution (includes all lung regions and the gastrointestinal tract) available for absorption into blood. Lead tetraoxide aerosol (concentration = 45 µg-Pb/m3) of monodisperse 3.0 µm MMAD particles (density = 8.3 g/cm3) were inhaled by an adult male sitting at rest for 8-h/day, 5 day/week, from age 20 to 40 years. The 5 days/week exposure was implemented by reducing the daily amount of air inhaled by 5/7 to smooth the illustrated lines. The daily dissolution includes gastrointestinal absorption of 9%