Abstract: At present,the generation schedule of coal-fired units based on the total air pollution of the whole system lacks the targeted regulation mechanism for mitigating air pollution concentration for densely populated areas.Thus,the differentiated environmental capacity constraints based on temporal and spatial dispersion characteristics of air pollutants are added to the conventional security-constrained unit commitment model.By curtailing the generation of coal-fired units that have severe impacts on air pollution concentration of densely populated areas to decrease the discharge capacity,the ambient air quality in these areas is improved and the health impact to human is decreased.In this model,the contribution from coal-fired units to the air pollutant concentration of densely populated areas is based on Gaussian puff dispersion model,forecasting meteorological information and forecasting pollution levels for key urban areas.The proposed model is formulated as a mixed integer programming problem and is simulated on a test system.The simulation results show that the proposed model with differentiated environmental capacity constraints can mitigate the health impact to human by the targeted regulation to the air pollution intensity in densely populated areas,without causing the noticeable degradation of system economy and air quality index.