title: Effect of race on fine particle deposition for oral and nasal breathing.
abstract: Nasal efficiency for removing fine particles from inhaled air may be affected by variations in nasal structure associated with race. In 11 African American and 11 Caucasian adults (age 18-31 yr) we measured the fractional deposition (DF) of fine particles (1 and 2 mum mass median aerodynamic diameter) (MMAD) for oral and nasal breathing using individual breathing patterns previously measured by respiratory inductance plethysmography during a graded exercise protocol. DF for both nasal and mouth breathing was measured separately by laser photometry at the same tidal volume and breathing rate for resting and light exercise (20% of maximum work load) conditions. From these DF measures, nasal deposition efficiency (NDE) was calculated for each condition. For light exercise conditions, NDE for both 1- and 2-microm particles was less in African Americans versus Caucasians, 0.15 +/- 0.07 (SD) versus 0.24 +/- 0.11 for 1-microm particles (p = .03), and 0.29 +/- 0.13 versus 0.44 +/- 0.11 for 2-microm particles (p = .006). The racial differences in NDE were associated with racial differences in nasal resistance and nostril shape. These race-dependent nasal efficiencies are dosimetric factors that should be considered in modeling and assessing particulate dose from human exposure to air pollutants.
authors.affiliation: Center for Environmental Medicine, Asthma and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. William_Bennett@med.unc.edu
authors.forename: William D
authors.initials: WD
authors.lastname: Bennett
authors.forename: Kirby L
authors.initials: KL
authors.lastname: Zeman
mesh_terms: D000293:Adolescent; D000328:Adult; D000336:Aerosols / Q000008:administration & dosage*; D001741:Black or African American; D000403:Airway Resistance; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009058:Mouth Breathing / Q000503:physiopathology*; D009666:Nose / Q000033:anatomy & histology / Q000502:physiology*; D010316:Particle Size; D012123:Pulmonary Ventilation; D012119:Respiration; D014885:Waxes; D044465:White People
chemical_list: D000336:Aerosols; D014885:Waxes; C026344:carnauba wax