Analysis of Total Respiratory Deposition of Inhaled Ultrafine Particles in Adult Subjects at Various Breathing Patterns
Titel:
Analysis of Total Respiratory Deposition of Inhaled Ultrafine Particles in Adult Subjects at Various Breathing Patterns
Auteur:
Kim, Chong S. Jaques, Peter A.
Verschenen in:
Aerosol science and technology
Paginering:
Jaargang 38 (2004) nr. 6 pagina's 525-540
Jaar:
2004-06
Inhoud:
Ultrafine particles are ubiquitous in the ambient air, and their unique physicochemical characteristics may pose a potential health hazard. Accurate lung dose information is essential to assess a potential health risk from exposure to these particles. In the present study, we measured total respiratory tract deposition fraction (TDF) of inert ultrafine aerosols (NMD = 0.04, 0.06, 0.08, and 0.10 μm and σg 1.3) in a group of young healthy adults (11 males and 11 females). A fast-response ultrafine condensation particle counter was used for continuous monitoring of inhaling aerosols breath by breath. Six different breathing patterns were used: three different tidal volumes (Vt = 500, 750, and 1000 ml) and two different flow rates for each Vt. The mean respiratory time (Tm) ranged from 2 to 4 s. The measured data showed that TDF increased with a decrease in particle size, thereby an increase in diffusion coefficient (D), and with an increase in Tm and Vt. For a given particle size both Tm and Vt were almost equally influential to TDF. TDF was generally comparable for men and women at the same breathing pattern. A slight increase in TDF was noticed for women only for smaller size particles (e.g., 0.04 μm). From the parametric analysis a composite parameter, (DTm)0.5Vkt, was identified by which all TDF data could be consolidated into a single curve (k = 0.49, (σ2 = 0.97). The results show that TDF of ultrafine particles can be reliably estimated by a unique empirical formula, and this may provide a convenient means of assessing respiratory dose of ultrafine particles.
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