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초분광센서를 활용한 이산화질소 농도 추정식에 관한 연구

Study on the Concentration Estimation Equation of Nitrogen Dioxide using Hyperspectral Sensor

  • 전의익 ((주)지오스토리 기술연구소) ;
  • 박진우 (한국국토정보공사) ;
  • 임성하 (한국국토정보공사) ;
  • 김동우 (한국환경정책.평가연구원) ;
  • 유재진 (한국환경정책.평가연구원 환경평가본부) ;
  • 손승우 (한국환경정책.평가연구원 환경평가본부) ;
  • 전형진 (한국환경정책.평가연구원) ;
  • 윤정호 (한국환경정책.평가연구원)
  • Jeon, Eui-Ik (R&D Center, Geostory Inc.) ;
  • Park, Jin-Woo (Division of Convergence, Korea Land and Geospatial InformatiX Corporation) ;
  • Lim, Seong-Ha (Division of Convergence, Korea Land and Geospatial InformatiX Corporation) ;
  • Kim, Dong-Woo (Department of Land and Water Environment Research, Korea Environment Institute) ;
  • Yu, Jae-Jin (Department of Environmentral Assessment) ;
  • Son, Seung-Woo (Department of Environmentral Assessment) ;
  • Jeon, Hyung-Jin (Department of Land and Water Environment Research, Korea Environment Institute) ;
  • Yoon, Jeong-Ho (Department of Land and Water Environment Research, Korea Environment Institute)
  • 투고 : 2019.05.10
  • 심사 : 2019.06.07
  • 발행 : 2019.06.30

초록

국내 산업단지에서 배출되는 대기오염물질의 모니터링을 위해 굴뚝원격감시시스템이 운영되고 있으나 대상 시설이 한정적이어서, 시스템이 설치되지 않은 시설은 단속 요원이 직접 모니터링 및 단속을 수행하고 있다. 그래서 효율적인 산업단지에서 배출되는 대기오염물질의 모니터링을 위해 다양한 센서를 활용한 연구들이 수행되고 있다. 이에 따라 본 연구에서는 초분광센서로 측정할 수 있는 분광복사량을 활용하여 대기오염물질 중 이산화질소의 농도를 추정할 수 있는 공식을 개발하고 검증하였다. 농도 추정식 개발을 위해 다양한 농도의 이산화질소를 대상으로 태양천정각, 관측천정각, 상대방위각을 다르게 하여 분광복사량을 관측하였다. 관측된 분광복사량에서 특정 파장 간의 값의 차이를 흡수 깊이로 하였으며, 흡수 깊이와 이산화질소 농도와의 관계를 이용하여 농도 추정식을 개발하였다. 그리고 개발된 농도 추정식들의 검증을 위해 이산화질소와 아황산가스가 혼합된 가스를 대상으로 측정한 분광복사량을 이용하였다. 그 결과, 추정식의 형태에 따라 결정 계수와 RMSE가 0.71~0.88, 72~323 ppm으로 나타났으며, 지수 형태의 농도 추정식의 결정 계수가 가장 높게 나타났다. 추정식의 형태에 따라 농도의 변화에 따른 추정 농도의 정확도가 일정하지 않지만, 향후 농도 추정식의 고도화가 이루어진다면 초분광 센서를 활용하여 산업단지 배출되는 이산화질소의 모니터링에 사용 가능할 것으로 판단된다.

The CleanSYS(Clean SYStem) is operated to monitor air pollutants emitted from specific industrial complexes in Korea. So the industrial complexes without the system are directly monitored by the control officers. For efficient monitoring, studies using various sensors have been conducted to monitor air pollutants emitted from industrial complex. In this study, hyperspectral sensors were used to model and verify the equations for estimating the concentration of $NO_2$(nitrogen dioxide) in air pollutants emitted. For development of the equations, spectral radiance were observed for $NO_2$ at various concentrations with different SZA(Solar Zenith Angle), VZA(Viewing Zenith Angle), and RAA(Relative Azimuth Angle). From the observed spectral radiance, the calculated value of the difference between the values of the specific wavelengths was taken as an absorption depth, and the equations were developed using the relationship between the depth and the $NO_2$ concentration. The spectral radiance mixed gas of $NO_2$ and $SO_2$(sulfur dioxide) was used to verify the equations. As a result, the $R^2$(coefficient of determination) and RMSE(Root Mean Square Error) were different from 0.71~0.88 and 72~23 ppm according to the form of the equation, and $R^2$ of the exponential form was the highest among the equations. Depending on the type of the equations, the accuracy of the estimated concentration with varying concentrations is not constant. However, if the equations are advanced in the future, hyperspectral sensors can be used to monitor the $NO_2$ emitted from the industrial complex.

키워드

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Fig. 1. Observation setting to estimate spectral radiance of NO2 using the hyperspectral sensor

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Fig. 2. NO2 spectral radiance. a for develop, b for examination of concentration estimation equations

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Fig. 3. NO2 concentration versus absorption depth with three concentration estimation equations

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Fig. 4. Relationships between measured concentration and estimated concentration

Table 1. Technical specifications of the hyperspectral sensor

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Table 2. Calculated absorption depth for developing the concentration estimation equations

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Table 3. Concentration estimation equations with R2 and RMSE

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Table 5. The statistics of measured concentration by the concentration estimation equations with measured concentration

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Table 4. Absorption depth according to NO2 concentration

SHGSCZ_2019_v20n6_19_t0005.png 이미지

참고문헌

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