## 2 Research Methodology: ABaCAS-Taiwan
### BenMAP  
Once the pollutant reductions that result from the implementation of some pollution control measures have been modeled using the aforementioned modules, the BenMAP module of the ABaCAS-Taiwan framework can be used to estimate the consequent health benefits of these improvements in air quality. BenMAP is a mature tool for assessing the health benefits of improvements in air quality, and has been employed in many countries [9; 22; 23; 30; 31; 32; 33; 34].  
BenMAP is an assessment tool based on the IPA framework [19; 20; 33]. Three types of technical parameters are required for BenMAP analysis: (1) The results of pollutant dispersal simulations, (2) health impact functions, and (3) monetization functions. In this study, the results of pollutant dispersal simulations were mainly derived from the simulation results of the RSM and SMAT modules. The change in health impact was evaluated using Equation (3), which is based on the BenMAP methodology:  
\[\Delta Y=Y_{0}\big{(}1-e^{-\beta\Delta\text{PM}}\big{)}\cross\text{{Pop}} \tag{3}\]  
In this equation, \(\Delta Y\) is the expectation value of the change in health events, with \(Y_{0}\) being the probability of health events in the baseline scenario; \(\beta\) is the literature-derived coefficient of estimation of the health impact function, and it is used to gauge the dependence of health events on pollutant concentrations; \(Pop\) is the size of the affected population. Equation (3) can be used to convert changesin pollutant concentration into an expected value of health impact, in units of occurrences. Numerous studies have been conducted to estimate the \(\beta\) value of each health event. In BenMAP, the \(\beta\) values obtained in each study can be unified into a representative \(\beta\) value through a meta-analysis of the pooled data. The unified \(\beta\) may then be used to assess health impacts [20]. In this study, a random-effects meta-analysis was performed to unify the \(\beta\) value.  
Finally, the economic cost of pollution can be estimated in BenMAP by monetizing the health impacts using Equation (4). Decreases in pollutant concentration will reduce the expected health impact, which then increases health benefits in the monetized assessment. Conversely, a rise in pollutant concentration will increase health costs:  
\[\textit{Economic Value}=\textit{Health Impact}\star\textit{Value of Health Impact} \tag{4}\]  
In Equation (4), _Health Impact_ is the expectation value of changes in the occurrence of a certain health event and is given by Equation (3); _Value of Health Impact_ refers to the monetized metric of this health event. The health impacts of air pollution generally include changes in morbidity and mortality risk. However, [PERSON] [35] noted that reductions in mortality risk accounted for over 98% of the health benefits that resulted from reductions in air pollution, whereas the reduction in medical costs owing to improvements in morbidity only accounted for approximately 2% of these health benefits. Therefore, this study will only focus on mortality risk when considering the health impact of air pollution. Changes in mortality risk were monetized using the value of statistic life (VSL) metric.