AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
A New Paradigm for Size Distribution Measurements Relevant to Aerosol Health Studies
AMANDA GRANTZ, Johannes Leppä, Richard Flagan, California Institute of Technology
Abstract Number: 375 Working Group: Instrumentation and Methods
Abstract With regard to particle size, evidence suggests that fine particles play a substantial role in affecting human health. Associations between PM2.5 and health endpoints are consistent, yet the role of ultrafine particles within this class has yet to be fully resolved. A research gap still exists in the development and deployment of inexpensive and widespread real-time monitoring instruments and methods for aerosol size distribution measurement. Size determinations are crucial for proper exposure assessments because particles of different sizes may deposit in different compartments of the human respiratory tract upon inhalation and possibly affect health in different ways. This study discusses whether high resolution measurements are necessary for prediction of lung dose in epidemiological time series studies or if there is potential for a new paradigm for collecting aerosol particle size measurements more simply and cost-effectively for health effects studies.
The arguments presented in this study are based on synthetic data describing aerosol populations measured in the environment. Particle number size distributions are simulated from published data and used as input for modeled measurement systems. These systems are modeled to recover size distributions with varying resolution. The ICRP model of particle deposition is then used to calculate deposition patterns in the human respiratory tract based on these measured particle size distributions. The deposited dose of particles is estimated for different regions of the human respiratory tract. Predicted deposition values are compared to ideally known deposition values, as calculated directly from the simulated input particle size distribution. Calculated dose biases are within ±10% even for measurement systems modeled to classify particle sizes with resolution values down to 3.