TY - JOUR T1 - Theoretical analysis of the influence of aerosol size distribution and physical activity on particle deposition pattern in human lungs JO - Scandinavian Journal of Work, Environment & Health PY - 2004/VL - 30 IS - 2 SP - 73 EP - 79 AU - Voutilainen, Arto AU - Kaipio, Jari P AU - Pekkanen, Juha AU - Timonen, Kirsi L AU - Ruuskanen, Juhani UR - https://www.sjweh.fi/show_abstract.php?abstract_id=817 KW - aerosol size distribution KW - human lung KW - modeling KW - particle deposition KW - particulate matter KW - physical activity KW - pulmonary deposition KW - urban aerosol N2 - '

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OBJECTIVES ': 'A theoretical comparison of modeled particle depositions in the human respiratory tract has been performed by taking into account different particle number and mass size distributions and physical activity in an urban environment.

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METHODS ': 'Urban air data on particulate concentrations in the size range 10 nm-10 µm were used to estimate the hourly average particle number and mass size distribution functions. The functions were then combined with the deposition probability functions obtained from a computerized ICRP 66 deposition model of the International Commission on Radiological Protection to calculate the numbers and masses of particles deposited in five regions of the respiratory tract of a male adult, the man`s physical activity and minute ventilation during the day being taken into account.

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RESULTS ': 'Two different mass and number size distributions of aerosol particles with equal (computed) <10 µm particle mass concentrations gave significantly different deposition patterns in the central and peripheral regions of the human respiratory tract. The deposited particle numbers and masses were much higher during the day (0700-1900) than during the night (1900-0700) because an increase in physical activity and ventilation were temporally associated with highly increased traffic-derived particles in urban outdoor air.

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CONCLUSIONS ': 'In future analyses of the short-term associations between particulate air pollution and health, it would not only be important to take into account the outdoor-to-indoor penetration of different particle sizes and human time-activity patterns, but also actual lung deposition patterns and physical activity in significant microenvironments.

SN - 0355-3140 ER -