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’, are walking on the fortress wall under the blue sky. yunhap news
It was confirmed that the concentration of ultrafine dust (PM2.5) nationwide last year was the lowest since 2015, when ultrafine dust observation began.
The National Institute of Environmental Sciences, affiliated with the Ministry of Environment, analyzed the observations of 472 national air pollution monitoring networks across the country. It was revealed on the 4th that it was lower than 20㎍/㎥.
This concentration is the lowest since 2015, when ultrafine dust observations began. It also decreased by 17.4% (4㎍/㎥) from 2019 (23㎍/㎥), recording the largest annual decline since 2015.
How did the concentration of ultrafine dust change? Graphic = Reporter Jaemin Shin [email protected]
The days when the concentration of ultrafine dust was’bad’ or higher (36㎍/㎥~) was also 27 days, which was 20 days less than the previous year. The worst air quality level,’very bad’ (more than 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.
Corona 19·China·Weather·Seasonal Management System
In the aftermath of Corona 19, the road around Gwanghwamun Square in Seoul is showing a busy appearance. Photo Joint 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 novel coronavirus infection (Corona 19). Corona 19 caused not only energy consumption but also traffic volume to decrease, and it emitted less pollutants, which affected air quality. In fact, last year’s domestic final energy consumption (January to September) decreased 3.8% compared to the previous year. The number of ships in and out of ports (January-October) also decreased by 7.6% from 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 promotes strong measures for fine dust, the annual average concentration of ultrafine dust in 337 regions across China has increased from 62㎍/㎥ in 2014 to 31㎍/㎥ in 2020 (January-November). It has decreased by 50%.”
Weather factors such as a lot of rain also worked to lower the concentration of fine dust. The national average rainfall last year was 1588.3mm, an increase of 34.1% from 1184.7mm in 2019. The number of days of air stagnation (days when the average wind speed is less than 2m/s) that directly affects high-density fine dust was 245 days last year, down 4.3% from 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, along with the National Fine Dust Information Center, is planning to conduct a detailed analysis of the causes of the improvement of ultrafine dust last year, such as changes in air pollutant emissions by region.
“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 weather.” We will reduce fine dust and greenhouse gases at the same time by reinforcing measures for each part such as industry, transportation, and power generation in line.”
Reporter Chun Kwon-pil [email protected]