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Trans-Pacific transport of tropospheric ozone from East Asia to the U.S. based on the CMAQ extended for hemispheric application (H-CMAQ) with the higher-order decoupled direct method (HDDM)
Citation:
Itahashi, S., C. Hogrefe, S. Napelenok, AND Y. Zhang. Trans-Pacific transport of tropospheric ozone from East Asia to the U.S. based on the CMAQ extended for hemispheric application (H-CMAQ) with the higher-order decoupled direct method (HDDM). 2018 CMAS Conference, Chapel Hill, NC, October 22 - 24, 2018.
Impact/Purpose:
As anthropogenic emissions from East Asia increase, they affect air quality not only on the regional scale but also on global scales. This work will improve our understanding of the role of trans-Pacific air pollution based on the state-of-the-art hemispheric modeling system.
Description:
As anthropogenic emissions from East Asia increase, they affect air quality not only on the regional scale but also on global scales. The Community Multiscale Air Quality (CMAQ) modeling system has been recently extended by the U.S. EPA to the hemispheric scale (H-CMAQ). Based on the H-CMAQ, we have performed a comprehensive analysis to study the trans-pacific transport of tropospheric ozone (O3) from East Asia to the U.S. We focus on April 2010 when exceedances of the U.S. National Ambient Air Quality Standard (NAAQS) for O3 were widely observed across the U.S. Comparisons with surface observation network, ozonesonde, and satellite showed that the H-CMAQ can capture O3 during April 2010. To investigate the trans-Pacific transport of O3, in this work, we employed the higher-order decoupled direct method (HDDM) technique in H-CMAQ. We found that ozone formation during April 2010 was limited by VOCs over East Asia whereas it was limited by NOx over the U.S. except California, the Great Lakes, and New England. We will analyze the sensitivities of the model predictions to region-specific emissions (i.e., East Asia and the U.S.) to quantify the impacts of air pollutants from East Asia on the U.S. air quality. This work will improve our understanding of the role of trans-Pacific air pollution based on the state-of-the-art hemispheric modeling system.
