TRACING THE RECENT CHANGE OF FINE DUST DENSITY IN SEOUL VIA STATISTICAL REASONINGSEOK HO CHANG AND SOONHUI LEE
The global economy shrank sharply in the first half of 2020 mainly due to COVID-19 pandemic and countriesâ tight control of their peopleâs movement. Our previous study (Chang and Lee 2021) presents that the average concentration of fine dust in Seoul has improved significantly in the first half of 2020 compared to before the coronavirus. However, as the economic activities of countries, including China and Republic of Korea, gradually resumed in the second half of 2020, some changes in air quality around the world, including Republic of Korea, have been observed. Although the Korean Government has recently implemented the second seasonal fine dust management system to reduce the intensity and frequency of fine dust by taking stronger emission reduction and management from December 2020, our analysis suggests that the average differences of the concentration of ultrafine dust in Seoul during the period from October 2020 to March 2021 and that from October 2019 to March 2020 are not statistically significant. We also make some brief comments on the implications of our findings.