• 환경영향평가
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• 제27권5호
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• pp.509-520
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• 2018

본 연구에서는 기상조건 변화에 따른 우리나라 $PM_{10}$ 농도변화 범위를 정량적으로 산정하기 위하여, 2010년에서 2014년까지(5년간) 모델의 입력자료인 국내외 배출량을 동일하게 가정하였을 때 기상조건에 따른 우리나라 $PM_{10}$ 농도변화 범위를 분석하였다. 본 분석에 사용된 모델은 WRF(ver.3.8.1)과 CMAQ(ver.5.0.2)이며, 기상 입력자료는 NCEP FNL $1^{\circ}{\times}1^{\circ}$ 자료, 국외 배출량 목록은 MIX 2010, 국내 배출량 목록은 CAPSS 2010을 이용하였다. 모델 모사결과는 2010년의 전국 일평균 $PM_{10}$ 농도에 대해 측정값과 0.82의 R값을 보이며 실제 $PM_{10}$ 농도의 증감경향을 잘 나타냈지만, 모델은 실제 $PM_{10}$ 농도와 비교하여 과소모의 하는 것으로 나타났다. 기상 및 대기질 모델을 통해 모사된 우리나라 연평균 $PM_{10}$ 농도는 기상조건의 변화로 인해 2010년 대비 평균적으로 약 $2.6{\mu}g/m^3$의 농도변화를 나타내었으며, 계절별로는 봄, 여름, 가을, 겨울에 대해 각각 $4.8{\mu}g/m^3$, $1.7{\mu}g/m^3$, $1.7{\mu}g/m^3$, $4.2{\mu}g/m^3$의 표준편차를 나타내며 봄철과 겨울철에 상대적으로 큰 $PM_{10}$ 농도 차이를 나타냈다. 전국 18개 권역을 대상으로한 지역별 분석 결과에서는 기상조건의 변화로 인해 모든 지역에서 연평균 $PM_{10}$ 농도가 $1.0{\mu}g/m^3$ 이상의 표준편차를 나타냈으며, 특히 서울과 경기북부, 경기남부, 강원영서, 충북 지역의 경우 $2.0{\mu}g/m^3$ 이상으로 타 지역에 비해 상대적으로 높은 차이를 나타냈다.

• 한국환경과학회지
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• 제20권3호
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• pp.405-416
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• 2011

In order to clarify the impact of regional warming on the ozone concentration according to the differences in meteorological contribution in each city over the South-Eastern part of the Korean Peninsula, several numerical experiments were carried out. WRF - CMAQ model was used to access the ozone differences in each case, during the episode day. Meteorological contributions estimated by WRF command a reasonable feature on the dispersion of ozone concentrations in each city according to regional warming. This causes a difference in estimated ozone concentration. A higher ozone concentration difference tend to be forecasted in coastal cities than in upcountry city. Therefore, the emission reduction policy according to the regional warming should consider the characteristics of meteorological contribution of each city.

• 한국대기환경학회지
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• 제21권1호
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• pp.49-62
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• 2005

Lake Paldang is a main resource of drinking water for 20 million people in the greater Seoul area. Dry deposition amounts of nitrogen and sulfur were estimated for three typical days in each season over the watershed of Lake Paldang. Models- 3/CMAQ (Community Multiscale Air Quality) and MM5 (Mesoscale Model) were used to predict air quality and meteorology, respectively. Aerosols as well as gaseous pollutants were considered. Nitrogen was mainly deposited in the form of HNO, while most of sulfur was deposited in the form of SO$_2$. Contribution of secondary pollutants was the largest in fall since they were transported from the greater Seoul area. However, contribution of secondarily-formed particulate pollutants to the nitrogen deposition was the largest in winter because semi-volatile ammonium nitrate favors lower temperature. Annual deposition amounts of nitrogen and sulfur were 37% and 26% of their emission amounts, respectively, over the watershed of Lake Paldang. Higher value of the nitrogen deposition showed a more influence of pollutants emitted in the greater Seoul area.

• 한국대기환경학회지
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• 제32권4호
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• pp.394-407
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• 2016

The spatial air pollution distribution of the Ulsan metropolitan region (UMR) was analyzed using monitoring data and high-resolution numerical simulations. A three-year (2011~2014) analysis for the average concentrations from the 13 air quality monitoring sites in the UMR showed that $SO_2$ and $PM_{10}$ levels in industrial regions were much higher than those in other regions, whereas spatial differences of $NO_2$ and CO concentrations were not significant. In particular, elevated $O_3$ concentrations were clearly found at urban sites near petrochemical complex area. Results from high-resolution simulations by CMAQ model performed for four months of 2012 showed large spatial variations in grid-average pollutant concentrations between industrial areas and other areas in the UMR, which displayed significant changes with wind pattern by season. It was noted that the increases of $SO_2$ and $PM_{10}$ levels were limited in costal industrial areas or over the area nearby the sea in all seasons. Modeled $O_3$ concentrations were quite low in industrial areas and main urban roads with large $NO_x$ emissions. However, the model presented that all pollutant concentrations were significantly increased in the urban residential areas near the industrial complexes in summer season with increase of southerly wind.

• 한국대기환경학회지
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• 제24권3호
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• pp.284-299
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• 2008

Emission input modules was developed to produce emission input data and change some profiles for Sparse Matrix Operator Kernel Emissions (SMOKE) using Clean Air Policy Support System (CAPSS)'s activities and previous studies. Specially, this study was focused to improve chemical speciation and temporal allocation profiles of SMOKE. At first, SCC cord mapping was done. 579 SCC cords of CAPSS were matched with EPA's one. Temporal allocation profiles were changed using CAPSS monthly activities. And Chemical speciation profiles were substituted using Kang et al. (2000) and Lee et al. (2005) studies and Kim et al. (2005) study. Simulation in Seoul Metropolitan Area (Seoul, Incheon, Gyeonggi) using MM5, SMOKE and CMAQ modeling system was done for effect analysis of changed input modules of SMOKE. Emission model results adjusted with new input modules were slightly changed as compared to using EPA's default modules. SMOKE outputs shows that aldehyde emissions were decreased 4.78% after changing chemical profiles, increased 0.85% after implementing new temporal profiles. Toluene emissions were decreased 18.56% by changing chemical speciation profiles, increased 0.67% by replacing temporal profiles as well. Simulated results of air quality were also slightly elevated by using new input modules. Continuous accumulation of domestic data and studies to develop input system for air quality modeling would produce more improved results of air quality prediction.

• 대기
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• 제32권4호
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• pp.341-351
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• 2022

Recently, interest in the possibility of a washout effect using artificial rain enhancement technology to reduce high-concentration fine dust is growing. Therefore, in this study, the reduction rate of PM₁₀ concentration according to the amount of artificial rain enhancement was calculated during Asian Dust event which occurred over the Korean Peninsula on March 29, 2021 using air quality model [i.e., Community Multiscale Air Quality (CMAQ)] combined with the mesoscale model for artificial rain enhancement (i.e., WRF-MMS). According to WRF-MMS, the washout effect lasted 5 hours, and the maximum precipitation rate was calculated to be 1.5 mm hr^-1. According the CMAQ results, the PM₁₀ reduction rate was up to 22%, and the affected area was calculated to be 6.4 times greater than that of the artificial rain enhancement area. Even if the maximum amount of precipitation per hour is lowered to 0.8 mm hr^-1 (about 50% level), the PM₁₀ reduction rate appears to be up to 16%. In other words, it is believed that this technique can be used as a direct method for reducing high-concentration fine dust even when the artificial rain enhancement effect is weak.

• 한국대기환경학회지
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• 제34권3호
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• pp.469-485
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• 2018

On September 26, 2017, South Korean government has established the Particulate Matter Comprehensive Plan to improve Korean air quality by 2022, which aims to reduce annual mean surface $PM_{2.5}$ concentration to $18{\mu}g/m^3$. This study demonstrates quantitative assessment of predicted $PM_{2.5}$ concentrations over 17 South Korean regions with the enforcement of the comprehensive plan. We utilize the Community Multi-scale Air Quality (CMAQ) modeling system with CAPSS 2013 and CREATE 2015 emissions inventories. Simulations are conducted for 2015 with the base emissions and the planned emissions, and impacts from model biases are minimized using the RRF (Relative Response Factor). With effective emission reduction scenario suggested by the comprehensive plan, the model demonstrates that the surface $PM_{2.5}$ concentration may decrease by $6{\mu}g/m^3$ ($23{\mu}g/m^3{\rightarrow}17{\mu}g/m^3$) and $7{\mu}g/m^3$ ($25{\mu}g/m^3{\rightarrow}18{\mu}g/m^3$) for Seoul and South Korea, respectively. The number of high $PM_{2.5}$ days(daily mean>$25{\mu}g/m^3$) also decreases from 21 days to 4 days.

• Asian Journal of Atmospheric Environment
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• 제9권4호
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• pp.259-271
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• 2015

This study conducted analyses on biogenic volatile organic compounds (BVOC) emission sources contributing to urban ozone ($O_3$) concentration in Osaka Prefecture, Japan in summer 2010 by using the Weather Research and Forecasting model (WRF) version 3.5.1 and the Community Multiscale Air Quality model (CMAQ) version 5.0.1. This prefecture is characterized by highly urbanized area with small forest area. The contributions of source regions surrounding Osaka were estimated by comparing the baseline case and zero-out cases for BVOC emissions from each source region. The zero-out emission runs showed that the BVOC emissions substantially contributed to urban $O_3$ concentration in Osaka (10.3 ppb: 15.9% of mean daily maximum 1-h $O_3$ concentration) with day-by-day variations of contributing source regions, which were qualitatively explained by backward trajectory analyses. Although $O_3$ concentrations were especially high on 23 July and 2 August 2010, the contribution of BVOC on 23 July (35.4 ppb: 25.6% of daily maximum $O_3$) was much larger than that on 2 August (20.9 ppb: 14.2% of daily maximum $O_3$). To investigate this difference, additional zero-out cases for anthropogenic VOC (AVOC) emissions from Osaka and for VOC emissions on the target days were performed. On 23 July, the urban $O_3$ concentration in Osaka was dominantly increased by the transport from the northwestern region outside Osaka with large contribution of $O_3$ that was produced through BVOC reactions by the day before and was retained over the nocturnal boundary layer. On 2 August, the concentration was dominantly increased by the local photochemical production inside Osaka under weak wind condition with the particularly large contribution of AVOC emitted from Osaka on the day.

• 한국대기환경학회지
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• 제34권5호
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• pp.708-726
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• 2018

In this study, we examined the contribution of nitrogen oxides and volatile organic compounds emitted from China and Japan to ozone concentrations over Gwangyang-bay, South Korea. We used a chemical transport model, Community Multi-scale Air Quality model, and its instrumented sensitivity tool, High-order Decoupled Direct Method. Intercontinental Chemical Transport Experiment-Phase B 2006 for East Asia and Clean Air Policy Support System 2007 emissions inventories for South Korea were used for the ozone simulation. During the study period, May 2007, the modeled maximum daily 8-hr average ozone concentration among seven air quality monitors in Gwangyang-bay was 68.8 ppb. The contribution of $NO_x$ emissions from China was 19.5 ppb (28%). The highest modeled ozone concentrations and Chinese contributions appeared when air parcels were originated from Shanghai area. The observed 8-hr average ozone concentrations in Gwangyang Bay exceeded the national ambient air quality standard (60 ppb) 203 times by daytime and 56 times by nighttime during the period. It was noticed that many exeedances happened when contribution of Chinese emissions to ozone concentrations over the area increased. Sensitivity analysis shows that a reduction in Chinese $NO_x$ and VOC emissions by 15% could lessen the total exceedance hours by 24%. This result indicates that high ozone concentrations over Gwangyang-bay are strongly enhanced by Chinese emissions.

• 한국대기환경학회지
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• 제33권2호
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• pp.139-158
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• 2017

CMAQ (Community Multiscale Air Quality Model) simulations were carried out to estimate the potential range of contributions on surface $PM_{2.5}$ concentrations over the Seoul Metropolitan Area (SMA) with the gaseous precursors and Primary Particulate Matters(PPM) available from a recent national emissions inventory. In detail, on top of a base simulation utilizing the 2013 Clean Air Policy Supporting System (CAPSS) emission inventory, a set of Brute Force Method (BFM) simulations after reducing anthropogenic $NO_x$, $SO_2$, $NH_3$, VOCs, and PPM emissions released from area, mobile, and point sources in SMA by 50% were performed in turn. Modeling results show that zero-out contributions(ZOC) of $NH_3$ and PPM emissions from SMA are as high as $4{\sim}5{\mu}g/m^3$ over the region during the modeling period. On the contrary, ZOC of local $NO_x$ and $SO_2$ emissions to SMA $PM_{2.5}$ are less than $1{\mu}g/m^3$. Moreover, model analyses indicate that a wintertime $NO_x$ reduction at least up to 50% increases SMA $PM_{2.5}$ concentrations, probably due to increased HNO3 formation and conversion to aerosols under more abundant ozone and radical conditions after the $NO_x$ reduction. However, a nation-wide $NO_x$ reduction decreased SMA $PM_{2.5}$ concentrations even during winter, which implies that nation-wide reductions would be more effective to curtail SMA $PM_{2.5}$ concentrations than localized efforts.