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| This Dec. 2, 2020, file photo shows a truck passing by a road sign that says vehicles with emission grade 5 are being inspected. Yonhap |
By Ko Dong-hwan
The government's seasonal monitoring of air quality has proven to be more effective this year than last, prompting the authorities to believe the fledging initiative can play a vital role in keeping the air clean.
The Ministry of Environment said May 25 the latest seasonal monitoring that was enforced from Dec. 1, 2020 to March 31 this year led to a greater reduction in the average concentration level of PM2.5 (particulate matter with a diameter of 2.5 micrometers or less) than when the regulation was first used from December 2019 to March 2020. The government added that the achievement comes even when the country's overall air quality tends to be worse then compared to the rest of the year. There have been more dust clouds and other air pollutants this year so far than the previous one, it said.
During the latest monitoring period, the average PM2.5 concentration level nationwide was 24.3 microgram per cubic meter. That was, according to the government, an improvement by 16 percent compared to the average from the past three years, which was 29.1.
The latest monitoring period also showed 35 "good" days and 20 "bad" days. (The national standard defines days with PM2.5 concentration level being 15 micrograms per cubic meter or lower as "good," while 36 or higher as "bad") The data beat the government's expectation, which forecast that the monitoring period would lower the country's average PM2.5 level to no further than 27.4 and the number of "bad" days would be no less than 24.
"If the seasonal monitoring period wasn't put into practice this year, we expect there would have been 10 fewer 'good' days and four more 'bad' days during the period this year," a ministry official said.
During seasonal monitoring periods, the government orders highways and other roads nationwide to be cleaned more frequently than during the rest of the period and enforces more stringent emission standards on local factories, businesses and vehicles. Automobiles with a grade 5 emission classification (the least-clean level in the country's five-tier system) were also banned from driving during those periods.
Following the latest seasonal monitoring period, the government said that amounts of environmentally harmful chemical emissions that have been saved were evident: PM2.5 was saved by over 6,200 tons, sulfur oxides over 42,000 tons, nitrogen oxides over 52,000 tons, and volatile organic compounds over 20,000 tons. Old diesel vehicles with a grade 5 emission classification also decreased in number from 2.1 million by the end of 2019 to 1.6 million by the end of March this year. In Seoul, which is home to one fifth of the country's 51 million population, concentration levels of nitrogen dioxide and elemental carbon, major pollutants from vehicle emissions, decreased. In the port cities of Incheon and Busan, sulfur dioxide and PM2.5 readings were also down, indicating that monitoring of emissions from ships also worked.
Overall, the latest monitoring period reduced over 121,000 tons of air pollutants linked to PM2.5 concentrations, the ministry said.
The effectiveness of the latest seasonal monitoring has been proven despite strong dust clouds that flew in over the country during March. There were 18 days when the dust clouds blanketed the country, while weak winds caused air to be trapped. The average number of such days throughout 2018-20 during the same month was 13. During the first seasonal monitoring period, there was only one day that triggered a warning of dust clouds from overseas, according to the ministry.
"Compared to the first seasonal monitoring period, the second one has been proven more effective in lowering concentration levels of PM2.5 and other air pollutants, showing that the initiative has worked well," the ministry official said. The government added that studies on the results of the latest seasonal monitoring period will lead to preparing measures to improve air quality for the upcoming third seasonal monitoring.
