이 연구의 목적은 2008년 5월 29일 우리나라에 영향을 미치는 황사를 예측하기 위해 WRF-Chem 모델 내 에어로졸 스킴과 광물성 먼지 옵션에 따른 미세먼지 농도 변화와 그에 따른 기상장의 민감도를 분석하는 것이다. 미세먼지의 인위적 배출량에 대해서는 0.5˚±0.5˚ RETRO 전구 배출량을, 광해리의 경우 Fast-J 광해리 스킴을, 그리고 황사 발생량을 추정하기 위해 RADM2 화학메커니즘 및 MADE/SORGAM 에어로졸 시나리오, MOSAIC 8 섹션 에어로졸 시나리오, 그리고 GOCART 먼지 침식 시나리오를 각각 적용하였다. 그 결과 RADM2 화학메커니즘 및 MADE/SORGAM 에어로졸 시나리오가 다른 시나리오들보다 우리나라 황사 먼지 농도와 배경 PM 농도를 더 높게 모사하였다. 그리고 이 시나리오와 서울의 각 대기질 측정망의 평균 PM10 농도와의 비교 결과, 상관계수는 0.67, 평균제곱근오차는 44μgm-3으로 나타났다. 또한 WRF-Chem 모델에서 상기 3가지 시나리오와 이들 시나리오가 없는 순수 기상에서의 온도, 풍속, 경계층 높이, 장파복사의 기상 민감도를 분석한 결과, 1,800-3,000 m 경계층 높이와 2-16ms-1 풍속 U 성분의 공간적 분포가 황사 먼지 발생의 공간적 분포와 유사하게 나타났다. 그리고 GOCART 먼지 침식 시나리오와 RADM2 화학메커니즘 및 MADE/SORGAM 에어로졸 시나리오는 황사 먼지 또는 에어로졸과 기상이 온라인으로 상호작용함으로써 지구장파복사가 더 낮게 모사되었다.
고형페기물 매립지에서 온실가스 배출량 산정은 기후변화에 대응 측면에서 매우 중요한 사항이다. 국내에서 메탄가스 배출량 산정은 주로 IPCC(Intergovernmental Panel on Climate Change)가이드라인에 근거하여 매립지 표면에서 직접적으로 flux chamber를 이용하여 배출량을 측정하거나, 또는 FOD(First Order Decay)방법에 의존하여 왔다. 그러나 FOD방법은 매립특성을 반영한 매립가스발생속도상수(k)를 정확히 산정하는데 어려움이 존재하고, 또한 표면 발산량을 측정하는 방법은 매립지 표면에서 배출량이 다양하고 측정이 한정된 기간에만 국한된다는 문제점을 내재하고 있다. 대안으로 본 연구에서는 plume measurement의 한 방법으로 대기확산모델을 활용한 역모델링기법을 적용하는 것을 검토하였다. 역모델링에 의해서 매립지 메탄가스 배출량을 직접 계산하기 위한 방법론을 정리하고, 실제 대전매립지에서 측정한 메탄농도를 이용하여 역모델링기법을 적용한 매립지 메탄 배출량 산정하는 방법에 대하여 제시하였다. 역모델링 과정을 검증하기 위해서 임의의 배출량으로 모델링을 수행하여 모델 예측농도와 확산변수 를 계산하였으며, 역으로 예측농도와 확산변수 를 이용하여 배출량을 재산정 하였다. 재산정한 배출량이 임의의 배출량과 동일함을 확인함으로써 본 연구에서 제시하고 있는 역모델링 절차가 적절함을 검증하였다. 또한, 본 연구에서는 역모델링 기법을 적용하여 실제 대전매립지를 대상으로 메탄 배출량 산정하였다. 대전매립지를 대상으로 메탄배출량을 산정한 결과 29.65~36.68 g/㎡-day로 산정되었으며, 주요 메탄 배출지점은 매립지 내의 유사한 지점에서 일관되게 나타났다. 본 연구방법은 기존의 방법과 비교하면, 메탄농도의 측정방법이 간단하고 비용이 적게 소요되므로 지속적인 모니터링이 가능한 장점이 있으며, 불균일한 매립지 표면의 배출량을 비교적 간편하게 산출이 가능한 것으로 파악되었다. 한편, 본 연구는 제한된 실험에 의한 결과이므로 향후 실제 매립지 배출량을 직접 측정하거나, 또는 추적자 실험을 통해서 그 방법론을 추가로 검증할 필요가 있는 것으로 판단된다.
Even though offensive odor control law was enforced in 2005, the civil appeal of odor doesn’t decrease all parts of the country. On Effluent Quality Standard site, the reason why the civil appeal is filed could be the restriction which is regulated by odor concentration(dilution threshold) without considering odor emission.
When regulating odor concentration only, the different scenarios were considered and analyzed for diffuse form through odor concentration, stack height and flow rate using AERSCREEN. Oder compounds from the analyzed scenarios were fluctuated by not only odor concentration but flow rate. Therefore, flow rate regulation introduction is necessary because odor concentration regulation of Effluent Quality Standard doesn’t make the civil appeal reduce.
Now, Odor Effluent Quality Standard is managed by Effluent Quality Standard like air pollutants in Korea. It means, the concept conversion of Receptor-centric is need for preventing civil appeal and complaint of odor. For the odor management of receptor-centric, workplace emission is regulated in accordance with odor concentration at receptor. but it’s hard to regulate all of workplace respectively because all workplace condition is different each other In Japan, odor diffusion modeling for calculating the causal relationship between receptor and emission is used for the method to figure out the problem. By expanding odor automatic monitoring network that some of local governments have, odor emission management and continues receptor current status analysis are needed to combine and operate for resolving odor problem.
There are many pollutants emitted into the air. Some of these pollutants have a malodor. Unlike other pollutants, people are able to detect and feel discomfort when this type of pollutant becomes high peak concentration instantaneously. In this sense, the peak concentration has an important meaning in the odor management and modeling. In previous odor modeling, the peak concentration was calculated by correcting the one-hour average concentration using the correlation equation. This study was carried out to find appropriate method to predict the peak concentration using meteorological input data of high time resolution in the odor modeling. It show that the peak concentration could be directly calculated from the dispersion modeling without using the correction equation when fine time scales such as 1 min or less time intervals are used as the meteorological input.
To improve modeling performance of CALPUFF in predicting dispersions of methane as the greenhouse gas and hydrogen sulfide as odor inducing pollutants emitted from Daejeon Landfill, we conducted tracer experiments of C2H2 and compared calculated concentrations by CALPUFF model under different dispersion coefficients with those measured as the tracer. The PG (Pasquill-Gillford) and micro- meteorological options in determining the dispersion coefficients in CALPUFF were tested against the tracer measurements. The results show that the micro-meteorological option, in which the dispersion coefficients are calculated by a similarity theory in planetary boundary layer, leads to a better agreement with the measured tracer concentrations than ISC-PG option.
MIt is important to estimate odor impact from the emission sources located in the industrial complex to near-by residential area. To understand modeling capacity in describing the odor dispersion, we examined an accuracy of odor modeling comparing with concentric measurements of sensory odors from the industrial complex. The odor measurements were carried out 6 times at 10 sites along the concentric circles and they were compared with odor modeling results using CALMET and CALPUFF. Although there are some discrepancies between the modeled and measured odor intensities, the model could depict key characteristics of odor dispersion patterns.
The uncertainties in emission data and meteorology were main causes of the discrepancies. The odor modeling procedure developed in this study can be used in odor forecasting system and odor impact assessment. In order to improve the accuracy of odor modeling, the improvement of odor emission data and systematic monitoring of the odor using sensor network are necessary in future.
In order to improve an accuracy of the real-time odor dispersion modeling system, a sensitivity of CALMET model with different input meteorological data was studied. The performance of CALMET model was tested by comparing the model predictions with the observations at the Daedeok Industrial Complex in Daejeon Metropolitan City. It is shown that the CALMET model with WRF (Weather Research and Forecasting) input data of GFS (Global Forecast System) depicts the measurements better than that of RDAPS (Regional Data Assimilation and Prediction System). The CALMET model could be further improved by selecting options of Divergence minimization, Froude number adjustment and Slope flows without choosing Kinematic Effects in the modeling procedure.
This study was carried out to find the optimal methods in odor dispersion modeling. The CALMET and CALPUFF recommended by US EPA were used in the study. The accuracy of 3 dimensional meteorological field was one of the important parameters in the modeling, To understand the sensitivity of CALMET according to meteorological input data, four Cases were tested and compared with the measurements. The four Cases with various input data were followed : Case 1 was surface and upper measured data, Case 2 was MM5 data only, Case 3 was surface weather station and MM5 data, Case 4 was surface weather station, upper-air weather station and MM5 data. The comparisons of wind speeds, wind direction and temperatures by CALMET model with observations under various input data showed that Case 4 was more accurate than the other Cases. The results of CALPUFF dispersion modeling were compared with odor complains data and they showed that there were similar patterns even if some discrepancies existed. CALPUFF dispersion modeling was also compared with odor monitoring station data, and there was a good agreement in the threshold odor concentrations. In order to get more accurate result for odor modeling, we need following additional measures: First, fine tuning of odor emission data with the consideration of variations of emission fate according to operation hour of the odor emitting facilities. Second, construction of continuous monitoring system(on-line GC, odor a sensor etc.) was necessary to monitor the odor compound concentrations.
In order to classify odors that are in the air at the specific place and at the specific period, it is necessary to generate representative patterns for each odor sources. In this study, in order to classify the various odors efficiently, the k-mean clustering algorithm was applied to the experimental data. Considering the mixed air with various odors, the representative patterns for odor sources were generated with the combination of two or three different odors. As a result, an acquired odor sample could be discriminated and hence its source can be traced by the proposed clustering method, in this study. The results of this study will be useful for settling the civil complaint related odor.
A three-dimensional Computational Fluid Dynamics (CFD) with the renormalization group (RNG) k-ε turbulence model was used to simulate flow patterns and corresponding dispersion of passive H₂S pollutant in urban area with complex terrains. The major emission sources of H₂S considered in this study include the sewage disposal plant and the leather waste water disposal plant located the northwest direction from the residential area. In order to describe the flow and dispersion characteristics of H₂S in the complex terrain, the terrain data in the modeling domain was processed as the input data for the CFD model, while the previous studies were conducted in flat terrains. The recirculating flow zone was formed behind the buildings, and the pollutant concentration in the zone was noticeably high because of limited ventilation. The velocity profile and ventilation rate along the height were calculated to identify the effective zone of weak flow and re-circulation by the buildings and complex terrains. According to this study, the CFD modeling was demonstrated to be highly effective to simulate the effect of buildings and complex terrains on the flow and dispersion of odors. Detailed studies are desirable to further validate the odor dispersion with measurements under more complex flow conditions.
Odor management area was introduced by Odor prevention laws in 2004. Odor is generated a lot of sources. It is generated from various process as well as stack outlet. So it is hard to control odor. The ministry of environment develops the system to control odor. Nineteen areas were selected as Odor management area. Odor management area should be conducted for periodical research on the actual condition. Odor is normally measured by Odor analysis method. However, there are some difficulties to conduct by Odor management area because of measurement frequency, limitation of areas and high cost. Therefore we need to figure out how to reinforce this performance in Odor management area. So we have checked possibility of monitoring system with realtime odor monitoring, electron sensor, mobile communication and odor modeling system. The Odor monitoring system is consist of realtime monitoring system and electron sensor system. The Odor monitoring system could be checked for odor concentration and source of odor by accessing internet and mobile communication.
There are many odor complains in Ansan and Siheung industrial complexes. In order to solve the odor problem, it is necessary to identify the major odor emission sources and to understand odor dispersion mechanism in these areas by applying the real-time odor monitoring system. The proposed system mainly consists of the measuring network of odor causing materials and meteorological variables as well as the dispersion modeling system on real-time base. In this study, the effective ways is also proposed to apply the system to ameliorate the odor environments.
In order to validate the meteorological and odor dispersion modeling methods, the measured meteorological parameters such as wind speed and direction and odor intensities were compared with those calculated from the models. The CALMET and CALPUFF models which were recommended by USEPA were used to predict the meteorological variable and odor concentrations. The average time of odor concentration was 10 mins. to consider instantaneous response nature of the odors. The results showed that model predictions were in good agreement with the measurements. It is expected that the modeling method presented in this paper will be useful to assess the impact of odors from industrial complex to near-by residential areas.
Odor emission effects of unit processes in 10 livestock farms and 3 manure treatment facilities in Y and I cities, Kyonggido, were simulated using puff model after the odor emission rates were measured. 2 degree level of odor intensity and 1 degree level of it were predicted by the puff model in the adjacent area of odor emission source and within the 8km radius range of it, respectively. As real time odor modelling system was operated at specific manure based fertilizer making facility located in Y city, the highest odor concentration was predicted at the entrance of that facility and relatively lower odor intensity was estimated at the place more or less be aparted from the emission sources. The higher odor intensity was evaluated at dawn and evening because the odor was accumulated in case of stable air condition.
Odor emission characteristics of unit processes in 10 livestock farms and 3 manure treatment facilities in Kyonggi province were examined in terms of odorous compound concentration and dilution ratio values of the threshold limit measured by instrumental analysis and air dilution sensory test, respectively. The highest odor concentration was detected at the compositing process unit of each facility and the dilution ratio showed high correlation with the treatment capacity as well as hygiene of the facility. Odor intensities in some facilities showed severe fluctuations (10 to 27 times difference) in response to the wind speed and direction as well as other weather conditions. According to the instrumental analysis, the major odorous compounds in the research area appeared to be ammonia, hydrogen sulfide, trimethyl amine, acetaldehyde and carbonyl compounds. Although some facilities breed same livestock, the types of odorous compounds as well as their concentration profiles were dependent on the type of composting process and management skill. In addition, dilution ratio of the threshold limit did not always show positive correlation with the odorous compound concentrations, which indicates the necessity of applying both methodologies, sensory test, and instrumental analysis.