▷ An analysis in South Chungcheong area showed that the fine dust level dropped by 15.4 percent from the previous two years (26→22μg/m3).
▷ According to the air quality modeling, the level of fine dust went down by 1.1 percent in South Chungcheong area and an average of 3.3 percent a month in the most affected area (at daily maximum 8.6 percent, hourly maximum 14.1 percent).
The Ministry of Environment (Minister Kim Eunkyung), the Ministry of Trade, Industry and Energy (Minister Paik Ungyu) and the National Institute of Environment Research (President Park Jinwon) announced that the shutdown of eight ageing coal-fired power plants nationwide over the month of June (4 in South Chungcheong, 2 in Sough Gyeongsang, 2 in Gangwon) led to an improvement in the level of fine dust, mainly in South Chungcheong area.
According to an analysis on 40 measuring points in South Chungcheong region, the level of fine dust went down by 15.4 percent to 22 micrograms per cubic meter from 26 micrograms per cubic meter, the average of the two previous years during the one-month period.
The reduction from the shutdown of coal plants was estimated to be 1.1 percent (0.3 micrograms per cubic meter). Yet, the level of fine dust at the most affected point showed a decrease of an average of 3.3 percent a month, a maximum of 8.6 percent a day and a maximum of 9.5 micrograms per cubic meter per hour.
The amount of reduced emissions was measured by using the national emissions data of four thermal plants in South Chungcheong region and real-time telemonitoring (TMS) system. The authorities analyzed fine dust and precursors such as SOx and Nox that generate secondary fine dust particles.
According to the analysis, the closure of the four plants in Boryeong and Seocheon in South Chungcheong resulted in a cut of 141 tons of emissions of fine dust, while 304 tons of emissions fell by the shutdown of eight plants across the country. The figure accounts for 15 percent of the 1,975 tons emitted by 53 coal-fired plants nationwide in June last year.
< Result of Fine Dust Concentrations >
The fine dust concentrations in South Chungcheong region was measured at 40 points by using measuring network, measuring device and simplified measuring device. The concentration of fine dust dropped by 4 micrograms per cubic meter from the previous two years’ average of 26 micrograms per cubic meter to 22 micrograms per cubic meter.
The weather conditions in June this year were similar to those of previous years including the days of precipitation and the average wind velocity, but other conditions such as the direction of wind and the influx of external pollutant were favorable compared to the previous years.
< Result of Modeling >
An air quality modeling (BMF method applied), which factored into weather conditions in June for the past three years, was conducted to compare the amount of emissions discharged from operating and non-operating aged plants.
The result showed that the one-month shutdown in South Chungcheong area led to a drop of 0.3 micrograms per cubic meter in the fine dust concentration level. And, at the most affected point, the dust concentration level showed a decrease of an average of 0.8 micrograms per cubic meter (3.3 percent) a month, a maximum of 0.8 micrograms per cubic meter (8.6 percent) a day and a maximum of 9.5 micrograms per cubic meter (14.1 percent) per hour.
Such improvement was mainly attributable to a drop in generation of secondary fine dust by SOx and NOx (96 percent) than a decrease in primary fine dust (4 percent).
When combining the results of fine dust measurement and air quality monitoring, fine dust in South Chungcheong went down an average of 4 micrograms per cubic meter a month, of which the reduction for the shutdown was 0.3 micrograms per cubic meter and the remaining 3.7 micrograms per cubic meter were due to a lower level of pollutants flowing from elsewhere and local weather conditions.
< Significance of Analysis>
The analysis showed that the temporary shutdown brought out improvements in the monthly average level of fine dust. In particular, the closure had a higher reduction effect in a short-term, which is relevant to human health.
According to NIER's research on citizens in Seoul in 2009, the mortality rate is projected to rise by 0.8 percent for all age group and 1.1 percent for the vulnerable aged 65 or above when the PM 2.5 level increases by 10 micrograms per cubic meter.
ME, NIER and MOTIE will use the results of analysis to set future policies on coal-fired power plants, and continue to carry out studies on the effect of the shutdown of plants next year.
Kim Jeong-su, Director of Climate and Air Quality Research Department of NIER, commented that "the analysis showed that the shutdown of aged coal-fired power plants is effective in reducing high concentration of fine dust in a short term."