On the Effectiveness of Emergency Reduction Measures for Ultrafine Dust Concentration in Seoul, Korea

Abstract

Since 2018, emergency reduction measures (ERMs) have been implemented by the Seoul Metropolitan Government to address air quality in Seoul, Republic of Korea. ERMs are activated when the concentration of ultrafine dust, particulate matter (PM) with an aerodynamic diameter of less than 2.5μm (PM 2.5), exceeds a certain level. In this study, using the daily time series data from 1 January 2018 to 31 June 2023, the effectiveness of ERMs is empirically analyzed by specifying multiple regression models in which PM 2.5 is explained not only by the days of ERMs but also by many other important factors. The empirical analysis shows that (i) PM 2.5 is influenced by its own past values up to three days; (ii) PM 2.5 is negatively influenced by both rainfall and wind speed, but positively related to temperature, humidity and yellow dust. The effect of PM 2.5 from the neighborhood (Dailan, China) is significantly positive; (iii) the effect of vehicle traffic volume and coal thermal power generation on PM 2.5 is not statistically significant; (iv) the effect of ERMs is not very strong when many important control variables are included in the regression equation. In conclusion, the ERMs do not play an effective role in reducing PM 2.5 over the whole period. However, it can be seen that the effectiveness of the ERMs has been increasing in recent years.