Method for planning subarea emission reduction strategies to improve ozone over a large area: A case of Taiwan

IF 4.2 2区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Atmospheric Environment Pub Date : 2025-03-04 DOI:10.1016/j.atmosenv.2025.121149

Tu-Fu Chen, Xin-Li Gong, Chang-You Tsai, Ken-Hui Chang

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引用次数: 0

Abstract

Inappropriate reduction strategies can exacerbate ozone pollution. While previous research has primarily focused on developing emission reduction strategies for large areas, this study aimed to create a method for quickly planning emission reductions in subareas within a larger area. Using Taiwan (large area) as an example, this study illustrates how to determine the emission reductions required in each county (subarea) to achieve a 50% reduction in the number of DM8O3 (daily maximum 8-h average ozone) pollution station-days across the entire region (the preset goal). The methodology began with observational data to calculate the expected DM8O3 concentration improvements needed to meet the preset goal. CMAQ-DDM simulations were then conducted to evaluate cross-county O₃ transport, revealing the reciprocal impact of emissions between counties on air quality. The results indicated that NO_X emission reductions caused O₃ deterioration, leading to a focus exclusively on NMHC reductions. A system of simultaneous linear equations was constructed to link emission reductions, the cross-county O₃ transport, and the expected improvements. Linear programming was applied to calculate the required NMHC reductions for each county. The findings showed that most counties needed to reduce NMHC emissions by 30%–40%, while some required only 20%. CMAQ simulations of the improvements resulting from these emission reductions (referred to as validated improvements) confirmed that they met the expected improvements in most counties and across Taiwan as a whole. Finally, a nonlinear correction factor, defined as the ratio of validated to linear improvements, was introduced to refine the system of linear equations. This refinement effectively addressed the biases associated with using a system of linear equations to represent the nonlinear processes of ozone formation and ensured that all counties achieved their expected improvements.

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来源期刊

Atmospheric Environment 环境科学-环境科学

CiteScore

9.40

自引率

8.00%

发文量

458

审稿时长

53 days

期刊介绍： Atmospheric Environment has an open access mirror journal Atmospheric Environment: X, sharing the same aims and scope, editorial team, submission system and rigorous peer review. Atmospheric Environment is the international journal for scientists in different disciplines related to atmospheric composition and its impacts. The journal publishes scientific articles with atmospheric relevance of emissions and depositions of gaseous and particulate compounds, chemical processes and physical effects in the atmosphere, as well as impacts of the changing atmospheric composition on human health, air quality, climate change, and ecosystems.