A heavily industrial nation, South Korea has one of the highest carbon emission production rates in the world. To participate in the global efforts to reduce carbon emissions, the South Korean government has recently proposed four national targets for carbon emission reduction: 14.7%, 19.2%, 25.7%, and 31.3% from the predicted 2030 BAU level. As the embodied environmental impacts of apartment building are becoming increasingly apparent, this study develops a carbon emission reduction policy model using a system dynamics approach to estimate the required amount of carbon emission reduction of apartment building construction. The results of this study indicate that apartment buildings require the reduction of 190 million kg CO2 for policy one, 248 million kg CO2 for policy two, 332 million kg CO2 for policy three, and 404 million kg CO2 for policy four, respectively, in the year 2030. This study also conducts a sensitivity analysis to investigate the impact of apartment floor demand on the expected total carbon emission amount and the carbon emission reduction amount of an apartment. Based on those results, this study develops a mathematical model for determining the optimal numbers of apartment units. (C) 2016 Elsevier B.V. All rights reserved.