The Seoul Metropolitan Government (SMG) confirmed that the city’s PM_2.5 levels hit a record low of 20 μg/m³. Ever since the city codified its urban air quality index and began recording PM_2.5 levels, this spring saw the most number of good air quality days (under 15 μg/m³) at 36 days, and only 11 days exceeded bad air quality levels.

The improvement of PM_2.5 levels can be seen as the result of a complex ripple effect made by municipal policies, weather conditions, and international factors. Especially, it is analyzed that the city’s policies on particulate matter has gained incredible momentum, considering the long-term trend of particulate matter reduction.

In particular, a record low measurement of 21 μg/m³ this past March when PM levels are usually at their highest is considered to have been impacted by the city’s enforcement of its seasonal PM management policy with strengthened reduction measures, such as increasing the PM reduction rate of large business sites and expanding the operation of street sweepers.

Weather conditions this spring were generally similar or somewhat unfavorable to those of the last three years, but the number of days of air stagnation greatly decreased from 23 last year to 8 this year, which seems to have had favorable influence.

Moreover, the city is taking its PM policies to prepare ozone policies in anticipation of high ozone levels this coming summer, focusing on reducing volatile organic compounds (VOCs), which greatly impact ozone air pollution when released into the atmosphere.

Seoul will respond with even more intensive control and management as it is expected that domestic and international emissions will most likely increase year over year due to the return to normalcy nationwide and worldwide, and it will do its best to protect citizens’ health through integrated management of ozone in summer and particulate matter in winter.