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Respiratory dose of inhaled particulate matter and its health implications in susceptible populations.
Citation:
KIM, C. S. Respiratory dose of inhaled particulate matter and its health implications in susceptible populations. Presented at Intl Society of Aerosols in Medicine, Monterrey, CA, May 10 - 14, 2009.
Impact/Purpose:
research results
Description:
Particulate matter (PM) in the air is known to cause adverse health effects, particularly in elderly subjects with respiratory and cardiopulmonary disease. Although observed health effects are likely caused by multiple factors, the respiratory dose is one factor of particular concern because pathophysiologic changes of the lung can alter deposition characteristics of PM. We have measured total and regional deposition of different size particles (Dp = 0.04–5 um) with various breathing patterns in the elderly and patients with asthma and COPD. In the elderly subjects, there were no significant differences (p<0.05) in both total and regional deposition compared with young adults indicating that age is not a contributing factor for lung deposition. In the patient groups, total and tracheobronchial deposition were greater but alveolar deposition was either unchanged (fine particles) or slightly decreased (coarse particles) compared with normals. Local deposition patterns showed a proximal shift of peak deposition sites and notable increase in local surface dose (50-200%) for fine and coarse particles. Both ultrafine and coarse particles were found to deposit in the generally same lung regions suggesting compounding effects of different size PM. Enhanced local dose and compounding size effects could play a crucial role in initiating adverse health effects and this needs to be incorporated in health risk assessment strategy. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.