Abstract
Evaluation of the accurate source-receptor relationships is important to understand the air quality over East Asia under the rapid changes in anthropogenic emissions resulting from economic shifts. When examining the sensitivity of variations of the model's input parameters to chemical concentrations, the brute force method (BFM) was the most commonly used, where input parameters are varied one-at-a-time. In this study, we applied the Higher-order Decoupled Direct Method (HDDM) to the case study of a trans-boundary air pollution episode occurred in springtime on 2007. HDDM provides an efficient and accurate approach for proving sensitivities, and could be applied to photochemical ozone (O3) involving complex nonlinear chemical formation processes. Based on the results of HDDM, we analyzed the ozone control regimes, and found that NOX sensitive region was dominate during the episode. The rapid increasing of NOX emissions in East Asia would be a possible reason for increment of O3 concentration during this episode in Japan. Applications of HDDM are to provide location- and time-dependent ozone isopleths via a parametric scaling method, and to assess the source contributions via a zero-out contribution (ZOC). During the episode, the contribution from anthropogenic emissions of China was approximately 30 %, and central eastern China (CEC) accounts for more than 50 % contribution. The usefulness of HDDM for the air quality studies over East Asia was demonstrated by this study.
