Externality reductions in residential areas due to rail transit networks

This work adopts a continuum approximation method based on long-term planning to describe the continuous characteristics of air pollution dispersion, street and rail transit network flow as well as household distribution. The model of air pollution distribution in a metropolitan area with surface streets and rail transit networks is constructed by applying dispersion equations of air pollutants in the field of Physics. Variations in air pollution due to decreased car flows, which result from commuters' shifting to the newly completed rail transit system, are also analyzed. Benefits from the reduction of air pollution are estimated by accumulating all of the exposed households at each residential site. Finally, a case study demonstrates the model application and estimates the improvement of residential environment in the Taipei metropolitan area due to the rail transit system.