In recent years, there have been increasing concerns on the management of particulate matter (PM) in Seoul. The city’s annual mean concentration of PM2.5 (of which diameter is less than 2.5 μm) is 2.5 times higher than the level outlined by the WHO’s guideline. In addition, premature deaths which have been attributed to PM2.5 was 1,762 people in 2015. Urban access regulation is one of the effective policy measures that have been put in place to address air pollution. Although Seoul has been operating the Low Emission Zone (designated areas where the most polluting vehicles are regulated) since 2010, the program’s impact on urban air pollution is limited because it covers only heavy-duty, diesel-powered, freight vehicles. For this reason, we propose a new urban access regulation in Seoul. The proposed regulation covers all kinds of cars (including passenger cars, gasoline/LPG cars, light-duty cars, foreign cars), of which emission level is 5 or more according to the national air quality certificate (ROK Ministry of Environment). In addition, detailed policy designs including designated areas, exceptions, enforcement systems, penalties, incentives, and long-term plans have also been proposed conducted on the issue, it was established that a majority of the general public support the scheme (77% of respondents agree) and many citizens (more than half) require more stringent application of the scheme. Once operational, it is expected that the scheme can reduce the total PM2.5 emissions of Seoul’s transport sector up to 27%, according to an application of the EMME2 transportation demand model.