환경영향평가시 대기확산모델의 적용에 관한 연구

Abstract

This study aims to develop effective environment assessment guidance by applying regional and project characteristics based intensive analysis tools on air-quality emphasized projects and by applying screening analysis tools on non-air-quality emphasized projects. Also, assessment contents for the stage of PERS and EIA are discussed, and the study results are summarizes for three categories as follows. First, each of Preliminary Environment Review System(PERS) and Environment Impact Assessment(EIA) has a different goal. However, it is hard to figure out those different characteristics of PERS and EIA from the actual reports. In order to clarify the content of PERS and EIA, the site-suitability should be mainly discussed in PERS. The development for mitigation plan, on the other hand, should be a main consideration in EIA. There are not so many differences in model application methods, but the secondary pollutant assessment, which has not been conducted by far, is required for both systems. Second, in order to better consider the effect of real topography in air quality modeling, AERMOD (The American Meteorological Society[AMS/EPA Regulatory MODel]) should take over ISCST3. AERMOD represents advances in the formulation of a steady-state, Gaussian plume model. It is apparent that AERMOD has an advantage over ISCST3 when the various scientific components are compared. Especially, AERMOD considers non-Gaussian plume in convective condition and accounts for a dispersion rate that is a continuous function of meteorology. In contrast, ISCST3 assumes that the dispersion rate is constant with height, and the plume is always Gaussian in form. Therefore, AERMOD is recommended over a complex terrain area. However, AERMOD has neither a lake breeze model to assess shoreline fumigation conditions nor is it capable of considering coastal and over-water interaction such as thermal internal boundary layer(TIBL) development. This prevents applying the AERMOD over coastline area with large point sources. A proper model that overcomes the limitation of AERMOD could be CALPUFF. CALPUFF is an integrated puff model capable of modeling instantaneous or continuous releases over distances ranging from hundreds of meters to hundreds of kilometers. In practice, the effect of a large point source could range over hundreds of kilometers. CALPUFF contains a meteorological preprocessor which produces a gridded three-dimensional flow fields of wind speed, wind direction, temperature, mixing layer height, and atmospheric turbulence, using available surface and upper air measurements. Also, CALPUFF includes a complex terrain algorithm(Complex 1) to account for the effect of elevated terrain on ground level concentrations, and a shoreline model to account for the formation of a thermal internal boundary layer due to land-water temperature differences. Therefore, CALPUFF is recommended over coastline area and complex terrain area with large point source. Third, screening method is required in construction and use process to improve the efficiency of assessment. At this point, we select all the items that can be waived advanced air quality modeling process in use process of EIA. Then, we can save the labor by virtue of the improved efficiency of the suggested method, which can be applied to construction process as good as use process. However, if the result of concentration from the screening method is greater than the national(province) standard value, then the advanced modeling should be conducted as next step.