SEOUL, SOUTH KOREA, April 9, 2018 – Seoul Health & Environment Research Institute announced its analysis of the causes for the high-density of fine dust (PM2.5) in Seoul from March 23rd to 27th.
According to the analysis of Seoul Health & Environment Research Institute, the fine dust came from abroad on the 24th March. And then, high pressure caused atmospheric congestion and heavy humidity made causative agent of fine dust in Korea accumulating. It led the high density of fine dust to remain until the morning of 26th March. Then, the density of fine dust got lower from the afternoon of the 26th. According to National Institute of Environmental Research, overseas effect※ stands at 58~69% from 23rd to 24th March (1st half of the period) and 32~51% from 25th to 26th March (2nd half of the period).
※ Overseas effect: Rate of the fine dust coming from abroad (including China) out of the density of fine dust in Korea (%)
The fine dust coming from abroad was added to fine dust in Korea. It caused high humidity and atmospheric congestion, which led to secondary formation of particles. The key causal factors for the high-density fine dust were nitrate, sulfate, and ammonium salt. On the 15th January at a time when the atmosphere had high-density fine dust, there was a clear increase in nitrate. However, the analysis of the high-density fine dust in March shows a clear increase in nitrate and ammonium ion. The analysis was made on the elements of the fine dust (PM2.5), measured by Seoul Air Pollution Monitoring Stations from the 24th to 26th March. It shows that the atmosphere during the 3 days had 3.1 times higher nitrate (NO3-), 3.4 times higher sulfate (SO42-) and 4.1 times higher ammonium salt (NH4++) than the average from the 1st to 23rd of March. This is quite different from the fine dust elements this January at a time when nitrate was noticeably increased.
Meanwhile, the analysis of the high-density fine dust in March showed the increase in the density of vanadium (V) and nickel (Ni). The two elements are said to be found in fine dust in case of the combustion of heavy oil. The analysis also looked at heavy metals in the fine dust (PM2.5) was measured by the Seoul city government from the 24th to 26th of March. As a result, vanadium (V) was 12 times higher (16.6ng/㎥) and nickel (Ni) was 5 times higher (7.3ng/㎥) than the average of March in 2016 and 2017, which is 2 times higher than this January with high-density fine dust.
Seoul Health & Environment Research Institute said that “there was a noticeable increase in nitrate on the 15th January of this year when it showed high-density fine dust, meanwhile, this March showed the increase of sulfate, ammonium salt, vanadium and nickel.”