• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.537-546
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• 2013

In the Seoul Metropolitan Area(SMA) photochemical air pollutants, nitrogenic compound and particulate matters have increased substantially due to mobile sources, power plants and so on. Therefore 'Special Act on Seoul Metropolitan Air Quality Improvement' was enacted on 2003 in order to improve air quality in the SMA. According to the Special Act, Central and local government have developed the state implementation plan(SIP) to reduce air pollutant emissions from various local sources. One of the key elements of the SIP development is the air quality modeling since modeling results can be used to establish emissions control strategies as well as to demonstrate attainment of air quality goals for ozone, particulate matter, and so on. Air quality modeling, therefore, can be usefully utilized to investigate the effects of government's efforts according to control strategies or measures. Using the air quality model, we can determine whether the implementation plan should be revised or not. A number of questions, however, has been raised concerning accuracy, consistency and transparency of modeling results because if we do not trust modeling results, all the measures dependent on modeling becomes in vain. So, without dealing with these questions, we can not guarantee the reliability and utilizability of air quality modeling results. In this study, we tried to establish standard methodology for air quality modeling in order to ensure consistency and transparency of modeling results used in the development and evaluation of national air policy. For this purpose, we established air quality modeling guideline to provide or recommend modeling procedures, vertical and horizontal domains, input data of meteorological and air quality modeling and so on.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.5
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• pp.625-638
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• 1999

Air quality modeling for coastal urban region has been composed of a complex system including meteorological, chemical and physical processes and emission characteristics in complex terrain. In this study, we studied about an effect prediction for deposition phenomenon affecting on air quality in Pusan metopolitan metropolitan city. In air quality modeling including ship sources, a situation considered deposition process habe better result than not considered when compared with observed value. Air pollutants emitted into urban air during the daytime nearly removed through urban atmosphere polluted. Also these phenomena correlated concentration variation connent with sea/land breezes and terrain effect. Therefore we conclude that the concentration was low at daytime when deposition flux is high, and deposition effect on industrial complex and Dongrae region is considerable in particular.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.4
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• pp.407-438
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• 2013

Current status and future direction of air quality modeling for monitoring and forecasting air quality in East Asia were discussed in this paper. An integrated air quality modeling system, combining (1) emission processing and modeling, (2) meteorological model simulation, (3) chemistry-transport model (CTM) simulation, (4) ground-based and satellite-retrieved observations, and (5) data assimilation, was introduced. Also, the strategies for future development of the integrated air quality modeling system in East Asia was discussed in this paper. In particular, it was emphasized that the successful use and development of the air quality modeling system should depend on the active applications of the data sets from incumbent and upcoming LEO/GEO (Low Earth Orbit/Geostationary Earth Orbit) satellites. This is particularly true, since Korea government successfully launched Geostationary Ocean Color Imager (GOCI) in June, 2010 and has another plan to launch Geostationary Environmental Monitoring Spectrometer (GEMS) in 2018, in order to monitor the air quality and emissions in/around the Korean peninsula as well as over East Asia.

• Asian Journal of Atmospheric Environment
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• v.11 no.4
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• pp.330-343
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• 2017

Climate change is an important issue, with many researches examining not only future climatic conditions, but also the interaction of climate and air quality. In this study, a new version of the emissions processing software tool - Python-based PRocessing Operator for Climate and Emission Scenarios (PROCES) - was developed to support climate and atmospheric chemistry modeling studies. PROCES was designed to cover global and regional scale modeling domains, which correspond to GEOS-Chem and CMAQ/CAMx models, respectively. This tool comprises of one main system and two units of external software. One of the external software units for this processing system was developed using the GIS commercial program, which was used to create spatial allocation profiles as an auxiliary database. The SMOKE-Asia emissions modeling system was linked to the main system as an external software, to create model-ready emissions for regional scale air quality modeling. The main system was coded in Python version 2.7, which includes several functions allowing general emissions processing steps, such as emissions interpolation, spatial allocation and chemical speciation, to create model-ready emissions and auxiliary inputs of SMOKE-Asia, as well as user-friendly functions related to emissions analysis, such as verification and visualization. Due to its flexible software architecture, PROCES can be applied to any pregridded emission data, as well as regional inventories. The application results of our new tool for global and regional (East Asia) scale modeling domain under RCP scenario for the years 1995-2006, 2015-2025, and 2040-2055 was quantitatively in good agreement with the reference data of RCPs.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.4
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• pp.430-439
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• 2007

The objective of this work is the air quality modeling according to the practical roughness length using the building information as surface boundary conditions. As accurate wind and temperature field are required to produce realistic urban air quality modeling, comparative simulations by various roughness length are discussed. The prognostic meteorological fields and air quality field over complex areas of Seoul, Korea are generated by the PSU/NCAR mesoscale model (MM5) and the Third Generation Community Multi-scale Air Quality Modeling System (Models-3/CMAQ), respectively. The simulated $O_3$ concentration on complex terrain and their interactions with the weak synoptic flow had relatively strong effects by the roughness length. A comparison of the three meteorological fields of respective roughness length reveals substantial localized differences in surface temperature and wind folds. Under these conditions, the ascended mixing height and weakened wind speed at night which induced the stable boundary stronger, and the difference of simulated $O_3$ concentration is $2{\sim}6\;ppb$.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.1
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• pp.30-40
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• 2011

Numerical simulations were carried out to investigate the impact of SST spatial distribution on the result of air quality modeling. Eulerian photochemical dispersion model CAMx (Comprehensive Air quality Model with eXtensions, version 4.50) was applied in this study and meteorological fields were prepared by RAMS (Regional Atmospheric Modeling System). Three different meteorological fields, due to different SST spatial distributions were used for air quality modeling to assess the sensitivity of CAMx modeling to the different meteorological input data. The horizontal distributions of surface ozone concentrations were analyzed and compared. In each case, the simulated ozone concentrations were different due to the discrepancies of horizontal SST distributions. The discrepancies of land-sea breeze velocity caused the difference of daytime and nighttime ozone concentrations. The result of statistic analysis also showed differences for each case. Case NG, which used meteorological fields with high resolution SST data was most successfully estimated correlation coefficient, root mean squared error and index of agreement value for ground level ozone concentration. The prediction accuracy was also improved clearly for case NG. In conclusion, the results suggest that SST spatial distribution plays an important role in the results of air quality modeling on high ozone episode at coastal region.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.E2
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• pp.75-81
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• 2003

Variational data assimilation, which is recently introduced to the air quality modeling, is a promising tool for obtaining optimal estimates of initial conditions and other important parameters such as emission and deposition rates. In this paper. two advanced techniques for variational data assimilation, based on the adjoint and quasi-inverse methods, are tested for a simple air quality problem. The four-dimensional variational assimilation (4D-Var) requires to run an adjoint model to provide the gradient information in an iterative minimization process, whereas the inverse 3D-Var (I3D-Var) seeks for optimal initial conditions directly by running a quasi -inverse model. For a process with small dissipation, I3D-Vu outperforms 4D-Var in both computing time and accuracy. Hybrid application which combines I3D-Var and standard 4D-Var is also suggested for efficient data assimilation in air quality problems.

• Journal of Environmental Science International
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• v.8 no.1
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• pp.135-144
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• 1999

Air quality modeling about coastal urban region such as Pusan shoud be consider shipping source emmited from ships anchoraging and running. It has been proved at our previous studies that the ratios of air pollutants emission amount in coastal area to inland are 12.2% for NO$_2$ and 11.7% for $SO_2$ and the air qualify of coastal urban area consierably counts on ships. Also the dispersion pattern of the all pollutants followed local circulation system in this region. Therefore this study has been developed air quality model which can describe the formation, transport, transformation and deposition processes of air pollutants considering shipping source. Currently, restriction for emission amount of ships does not exist, so our study will be useful to set the omission standard and for devising air quality policy in coastal urban region.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.6
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• pp.563-576
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• 1998

To study the influences of the emission sources during lune 13∼15 1997 in Seoul, MESOPVFF II model has been used. The MESOPVFF II model includes terrain effects, chemical transformation and removal processes. Data of 20 surface meteorological stations and the upper air station on mid-west area in Korea were used as a DWM (Diagnostic Wind Model) input data. This model is likely to be applicable because the predicted SO2 concentration was well matched with measured 502 concentration in Seoul and Kyonggido. In generally air pollutants in Seoul have major influence on the other cities but the result of modeling appeared also air pollutants of the other cities influence on Seoul. Finally, in the case of calculating the air quality by diffusion model, the influences of air pollutants emitted in metropolitan area as well as the emission rate in modeling area should be considered.

• Journal of Environmental Impact Assessment
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• v.16 no.6
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• pp.381-391
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• 2007

The air quality modeling was carried out to assess the impact of air quality for large scale urban development. The site for the assessment is Multi-fuctional Administrative City which locates in Yeongi-gun, Chungcheongnam-do and estimated population in 2030 is 500,000. Two automatic weather monitoring stations were installed to monitor the meteorological variables for a year and upper air meteorological parameters were measured using radiosonde for 5 days with 4 hours interval in every season. The air quality of standard air pollutants were also measured for 5 days continuously in every season. The results of wind field analysis based on the site measurements and CALMET modeling showed that the valley and mountain winds were prevailed when the sypnotic wind was weak. It also showed that wind speed and directions were highly space-variable within the site basin. The variable wind characteristics implies that the Gaussian dispersion model such ISC3 and AERMOD are not appropriate and the unsteady-sate Lagrangian model such as CALPUFF is preferable. CALPUFF model was applied to assess air quality impact of new sources. The new sources were those for individual and group heating facilities as well as the traffic increases. The results showed that the estimated concentrations of CO and $SO_2$ pollutants by summing the impact concentration of new sources by the dispersion model and the ambient air concentrations by the site measurements were acceptable but those of PM-10 and $NO_2$ would violate ambient air quality standards at several locations due to high ambient air concentrations. It is recommended that the emission reductions near the site should be enforced to improve the ambient air quality.