Abstract Air pollution, a by-product of economic growth, has been incurring extensive environmental costs in Seoul, Korea. Unfortunately, air pollution impacts are not treated as a commercial item, and thus it is difficult to measure the environmental costs arising from air pollution. There is an imminent need to find a way to measure air pollution impacts so that appropriate actions can be taken to control air pollution. Therefore, this study attempts to apply a choice experiment to quantifying the environmental costs of four air pollution impacts (mortality, morbidity, soiling damage, and poor visibility), using a specific case study of Seoul. We consider the trade-offs between price and attributes of air pollution impacts for selecting a preferred alternative and derive the marginal willingness to pay (WTP) estimate for each attribute. According to the results, the households’ monthly WTP for a 10% reduction in the concentrations of major pollutants in Seoul was found to be approximately 5494 Korean won (USD 4.6) and the total annual WTP for the entire population of Seoul was about 203.4 billion Korean won (USD 169.5 million). This study is expected to provide policy-makers with useful information for evaluating and planning environmental policies relating specifically to air pollution.