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Citizens who visited Changryongmun, a world cultural heritage site in Suwon-si, Gyeonggi-do, on December 30, when the concentration of fine dust was “good”, walk on the fortress wall under the blue sky. Yunhap news
The concentration of ultrafine dust (PM2.5) across the country last year was confirmed to be the lowest since 2015, when ultrafine dust observation began.
The National Institute of Environmental Sciences, affiliated with the Ministry of the Environment, analyzed the observations of 472 national networks for monitoring air pollution throughout the country. On the 4th it was revealed to be less than 20㎍ / ㎥.
This concentration is the lowest since 2015, when ultrafine dust observation began. It also decreased by 17.4% (4㎍ / ㎥) since 2019 (23㎍ / ㎥), registering the largest annual decline since 2015.
How did the concentration of ultrafine powder change? Graphic = Reporter Jaemin Shin [email protected]
The days when the ultrafine dust concentration was “bad” or higher (36㎍ / ㎥ ~) was also a total of 27 days, 20 days less than the previous year. The worst level of air quality, ‘very bad’ (over 76㎍ / ㎥) occurred six days last year, but never last year. On the other hand, the number of ‘good’ days (less than 15㎍ / ㎥) was 154 days, an increase of 39 days compared to 2019, and was recorded as the year with the most clear days since the observation.
Corona 19 · China · Climate · Seasonal management system
In the wake of Corona 19, the road around Gwanghwamun Square in Seoul looks busy. Joint Photo Report Group
The National Institute of Environmental Sciences analyzed four reasons why the concentration of ultrafine dust was low last year. The first is the aftermath of the new coronavirus infection (Corona 19). Corona 19 caused not only energy consumption, but also less traffic and fewer pollutants, affecting air quality. In fact, the final internal energy consumption of last year (January to September) decreased by 3.8% compared to the previous year. The number of ships entering and leaving the ports (January-October) also decreased by 7.6% compared to the previous year, and the number of air flights (January-November) decreased by 43.7%.
The decrease in fine dust from China, one of the main causes of high concentration, also affected. The National Academy of Environmental Sciences said: “As China promoted strong measures for fine dust, the annual average concentration of ultrafine dust in 337 regions of China has increased from 62㎍ / ㎥ in 2014 to 31㎍ / ㎥ in 2020 ( January ~ November). It has decreased by 50%. ”
Climatic factors, such as a lot of rain, also contributed to reducing the concentration of fine dust. The national average precipitation last year was 1588.3 mm, an increase of 34.1% from the 1184.7 mm in 2019. The number of days of stagnant air (days with an average wind speed of 2 m / s or less), which directly affects high-density fine dust, was 245 days last year, 4.3% less than the previous year (256 days).
In addition, the National Institute of Environmental Sciences explained that strengthened domestic air pollution regulation policies, such as the seasonal management system, which was first introduced last winter, have also been effective in reducing the concentration of fine dust. The National Academy of Environmental Sciences, together with the National Fine Dust Information Center, plans to conduct a detailed analysis of the causes of the ultrafine dust improvement last year, such as changes in air pollutant emissions by region.
Kim Young-woo, director of climate and atmospheric research at the National Institute of Environmental Sciences, said: “The concentration of ultrafine dust in 2020 was the lowest since observation, but high concentrations of fine dust can still occur at any time depending on external factors such as the weather. ” We will reduce fine dust and greenhouse gases at the same time by reinforcing measures for each part, such as industry, transport and online power generation. ”
Reporter Chun Kwon-pil [email protected]
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