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Development of a semi-mechanistic allergenic pollen emission model
Citation:
Cai, T., Y. Zhang, X. Ren, L. Bielory, Z. Mi, Chris Nolte, Y. Gao, R. Leung, AND P. Georgopoulos. Development of a semi-mechanistic allergenic pollen emission model. SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, Netherlands, 653:947-957, (2019). https://doi.org/10.1016/j.scitotenv.2018.10.243
Impact/Purpose:
This paper describes the development of a semi-mechanistic model for estimating the emission of ragweed and oak pollen. Many people are allergic to these two species, and airborne exposure to these pollen particles can cause a variety of health impacts, including asthma.
Description:
Modeling pollen emission is crucial for studying the spatiotemporal distributions of allergenic pollen. A semi-mechanistic emission model was developed based on mass balance of pollen grain fluxes in the near surroundings of allergenic plants. The emission model consists of direct emission and resuspension, and it accounts for influences of temperature, wind velocity, and relative humidity. Modules of this emission model have been developed and parameterized to provide pollen season onset and duration, hourly flowering likelihood, and vegetation coverage for oak and ragweed, as two examples. The simulated spatiotemporal pattern of pollen emissions generally follows the corresponding pattern of area coverage of allergenic plants and diurnal pattern of hourly flowering likelihood. It is found that oak pollen emissions start from the Southern part of the Contiguous United States (CONUS) in March and then shift gradually toward Northern CONUS, with a maximum emission flux of 5.8 x 10^6 pollen/(m2 h). On the other hand, ragweed pollen emissions start from Northern CONUS in August and then shift gradually toward Southern CONUS. The mean ragweed emission flux during August to September can go up to 2.4 x10^6 32 pollen/(m2 h), with a maximum of 8 x 10^7 pollen/(m2 h). The emission model is robust with respect to the input parameters of oak and ragweed. This model could also be applied to other pollen species given the related parameters.
