People read books at an outdoor library at Seoul Plaza in Jung District, Friday. Yonhap
Seoul's fine dust levels have dropped significantly over the past two decades, marking a hard-won turnaround even as ozone is looming to be the capital's next air quality threat.
The Seoul Metropolitan Government said Wednesday that the annual average concentration of ultrafine dust, or PM2.5, fell 40 percent from 30 micrograms per cubic meter in 2006 to 18 micrograms in 2025. Fine dust, or PM10, dropped 47 percent over the same period, from 60 micrograms to 32 micrograms.
Days with poor PM2.5 levels, defined as concentrations at or above 36 micrograms per cubic meter, fell from 108 in 2006 to 32 last year, while days with clean air, at or below 15 micrograms, more than doubled from 73 to 182 over the same period.
The city credited the gains largely to the de-dieselization of its bus fleet. Between 2006 and 2014, Seoul converted about 8,900 diesel buses to compressed natural gas and other cleaner alternatives. The shift has continued since, with electric buses now making up about 23 percent of the city's fleet.
Fitting aging diesel vehicles with particulate filters and subsidizing early scrapping also contributed, with such measures completed for about 530,000 vehicles as of last year. The city also plans to replace about 400 buses with electric models this year.
However, the improvements have not extended to all pollutants. Seoul's ozone levels rose more than 48 percent between 2015 and 2025 to 0.0326 parts per million, a particular concern for children and the elderly, who are most vulnerable to its effects on the eyes and respiratory tract.
To address the problem, the city will run a seasonal ozone campaign through August, inspecting about 1,030 volatile organic compound-emitting facilities including gas stations, painting shops and dry cleaners.
“As fine dust levels show steady improvement, we will now turn our attention to ozone, which affects citizens' health in summer,” said Kwon Min, director-general of the city's Climate and Environment Bureau, adding that Seoul aims to create year-round clean air through source-specific reduction measures and public awareness campaigns.
Source: Korea Times News
