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DEPOSITION PATTERNS OF RAGWEED POLLEN IN THE HUMAN RESPIRATORY TRACT
Citation:
Martonen, T. AND M. O'Rourke. DEPOSITION PATTERNS OF RAGWEED POLLEN IN THE HUMAN RESPIRATORY TRACT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-92/312.
Description:
Inhaled particle deposition sites must be identified to effectively treat human airway diseases. e have determined distribution patterns of a selected aeroallergen, ragweed pollen, among human extrathoracic (ET: .e., oro-nasopharyngeal) regions and the lung. A predictive model validated by inhalation exposure data from human subjects was utilized. eposition locations were primarily functions of (i) ragweed particle parameters (size, 14-20 um; shape, spherical; and density, 1.14 g cm-3) and (ii) mode of breathing. n the general population, two styles of inhalation are prevalent: ormal augmenters (NAs), and mouth breathers (MBs), their clinical definitions are based on intra-ET airflow divisions. or a MA-mode breathing, sedentary (10 L min-1) adult, 88% of inhaled ragweed pollen was removed by the ET compartment and 7.0% collected within the lung. or a MB, the respective deposition efficiencies were 68% and 25%. To amply the model, we used a daily springtime ragweed pollen concentration of 300 grains m and an exposure time of 0.5 hour to calculate actual doses for the respiratory system. Under the stipulated conditions, a MS would inhale 45 pollen grains per day and 8 would be deposited in the lung; the value is 3 grains for a MA. requently, individuals with impaired respiratory functions are MBs in whom such pollen deposits are likely contributors to airway disease.