Assessment of acid deposition over Dhaka division using CAMx–MM5 modeling system

Developmental Biology

Asif Iqbal¹  Nguyen Thi Kim Oanh¹ 

[1] Environmental Engineering and Management, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand$$

关键词: Emission inventory;    Acid deposition;    Dispersion modeling;    Long range transport;    Bangladesh;   

DOI  :  10.5094/APR.2011.052

学科分类：农业科学（综合）

来源: Dokuz Eylul Universitesi * Department of Environmental Engineering

【 摘 要 】

This study provided an insight into the complex phenomenon of acid deposition over Dhaka division of Bangladesh. The 10– day HYSPLIT back trajectories showed that majority of air masses arriving to Bangladesh were originated from the west. The gridded emissions (0.055° or ~5.5 km) for Dhaka division was prepared for 2006 by updating a preliminary emission inventory (EI) available for 2000 and by conducting a new EI for two major source categories, brick kilns and traffic. In Dhaka division as of 2006, the brick kilns contributed the largest SO₂ emission (about 70%), while residential emissions had the highest share of CO and PM₁₀ (over 60%) and substantial NMVOC (about 40%). Emission rates of SO₂ and NO_x in the dry season of 355 t/d and 183 t/d, respectively, were higher than the corresponding rates in the wet season of 60 t/d and 146 t/d, which was mainly due to the operation of brick kilns in the dry season. The acid deposition was simulated, using CAMx–MM5 model, for December and June to represent the dry and wet seasons, respectively. Model performance was reasonable considering the simulated spatial distribution of acid deposition with simulated wind and precipitation fields. The model results for SO₂ and NO_x concentrations were in the same ranges of the limited monitoring data available. However, the acid deposition simulation was still largely experimental due to the lack of acid deposition monitoring data for the model evaluation. The preliminary acid deposition simulation results suggested that the nitrogen wet deposition was the major contributor over the Dhaka division that could be the reason of exceeding the critical load for the local ecosystem. Further research is still required to refine the emission inventory and to gather the monitoring data to confirm the modeling results.

【 授权许可】

Unknown   

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