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NASAL FILTERING OF FINE PARTICLES IN CHILDREN VS. ADULTS
Citation:
BENNETT, W. D. AND K. L. ZEMEN. NASAL FILTERING OF FINE PARTICLES IN CHILDREN VS. ADULTS. Presented at International Society for Aerosols in Medicine, Perth, AUSTRALIA, March 14 - 18, 2005.
Description:
Nasal efficiency for removing fine particles may be affected by developmental changes in nasal structure associated with age. In healthy Caucasian children (age 6-13, n=17) and adults (age 18-28, n=11) we measured the fractional deposition (DF) of fine particles (1 and 2um MMAD) for oral and nasal breathing using individual breathing patterns previously determined by respiratory inductance plethysmography during a graded exercise protocol. DF for both nasal and mouth breathing were measured separately by laser photometry at the same tidal volume and breathing rate for resting and light exercise (20% max work load) conditions. From these DF measures, nasal deposition efficiency (NDE) was calculated for each condition. We found that NDE for 2um particles was significantly less in the children vs. adults for their light exercise ventilation patterns, 0.25+/-0.16 vs. 0.44+/-0.11 respectively, p<0.002, i.e. the condition for highest deposition by impaction in the nasal airways. NDE under this condition increased significantly with childs height and age (r = 0.62 and 0.59, p<0.05). NDE did not differ between children and adults for the 1um particles and/or resting breathing conditions. These results suggest that due to less efficient nasal filtering of particles the lungs of children may be exposed to higher concentrations of inhaled, ambient particles than adults. Supported by USEPA Cooperative Agreement CR829522 but does not necessarily reflect EPA policy.