American Association for Aerosol Research - Abstract Submission

AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA

Abstract View


An Integrated Modeling Approach to Understand the Interaction between Air Pollution and Pollen Allergy in a Changing World

RUI ZHANG, Tiffany Duhl, Muhammed T. Salam, James House, Richard Flagan, Ed Avol, Frank Gilliland, Alex Guenther, Serena H. Chung, Brian K. Lamb, Timothy M. VanReken, Washington State University

     Abstract Number: 403
     Working Group: Bioaerosols: Characterization and Environmental Impact

Abstract
There is growing evidence that air pollutants can interact with inhalant allergens carried by pollen grains to enhance the risk of allergic airway disease (AAD) for sensitive populations. Linking air pollutants, pollen levels, and human allergenic response using an integrated modeling approach is a key step toward quantifying the overall health impacts under current and future climate conditions. A regional-scale pollen release and transport modeling framework has been developed within the WRF/CMAQ air-quality modeling system. The Simulator of the Timing and Magnitude of Pollen Season (STaMPS) model was developed to estimate the daily pool of pollen available for release by wind. It is driven by species-specific meteorological threshold conditions and is flexible with respect to the representation of vegetation species and plant functional types. The hourly pollen emission flux is then parameterized using the pollen pool, friction velocity, and wind threshold values. Dry deposition for each species of pollen is estimated based on pollen grain size and density.

An evaluation of this new modeling framework was conducted during the 2010 pollen season for southern California. The simulation period coincided with observations by the University of Southern California's Children's Health Study (CHS), which included ozone, PM2.5, and pollen count, as well as measurements of exhaled nitric oxide in study participants. Two nested domains with horizontal grid cells of 12 km and 4 km were constructed and seven representative allergenic pollen genera were included: birch, walnut, mulberry, olive, oak, sagebrush, and grasses. The modeling framework tends to underestimate peaks in oak and overestimate grass pollen concentrations, but it shows reasonable agreement with observed concentrations for other species. For future work, the modeled pollen, ozone, and PM2.5 concentrations will be used to evaluate species-specific pollen allergen dose response functions to understand the interaction between air pollution, pollen level, and respiratory health outcomes.