open path monitoring 법응용 대기가스측정및분석

Transcription

1 open path monitoring 법응용 대기가스측정및분석 이정순 한구표준과학연구원

2 Open path monitoring Horizontal or vertical? (Malm, 2000) Open path monitoring: 시정, 오존, UV 지수, 연직분포 2

3 Atmospheric Environmental Sensing Scattering process Raman scattering Laser-induced fluorescence (LIF) Light detection and ranging (LIDAR) Absorption process IR absorption Spectroscopy (FTIR) Differential Optical Absorption Spectroscopy LongPath absorption spectroscopy with Laser Differential absorption Lidar, TDLAS Photo-acoustic spectroscopy (PAS) with Laser Emission process LIBS 3

4 Why open-path path? Direct multiple measurement - 시료의전처리가필요없다 In-situ measurement - 현장실시간측정이가능하다. Absolute measurement Calibration 이필요하지않다. Intact measurement Absorption spectrum -> 정량분석 global monitoring: 대기조성 / 화학연구 4

5 대기특성스펙트럼? 5

6 대기중의물질의 양 측정 산란 (elastic/inelastic; Raman ) 방출흡수 Lambert-Beer의법칙 흡수체가광경로내균질한분포를이룰때, 흡수도 (A) 는흡수물질의농도에비례한다. 흡수도 (A) 는경로의거리에비례한다. L L light path length σ (λ) absorption cross-section c concentration of gas C = A = σ (λ)lc 1 σ( λ) L ln[ I( λ) / I ( λ)] 0 6

7 FTIR 응용 Quantitative analysis - FTIR: 온실기체의 multiple 정량분석 -측정방법별inter-comparison 실시 (CO 2 : NDIR, CH 4 : GC-FID, N 2 O: GC-ECD) - 표준가스개발 In-situ gas 성분분석 - 배경대기수준의농도측정실시 Trace gas analysis -open path를적용 7

8 LIDAR 응용 Distance 연직분포측정 Speed forecasting : wind/temp.,,, Rotation Optical properties Atmospheric Composition 온실기체측정 : water vapour, carbon dioxide, methane, chloroflurocarbons (CFCs) and ozone dust/vapor/cloud 특성측정 8

9 DOAS 응용 광경로내의다중가스들의평균농도측정 9

10 Target of open-path path monitoring (1) Composition of air (Earth s atmosphere) Air : mixture of gases and particles (atmospheric aerosols Cloud: clouds of condensed water, and ice cloud Variable gases: water vapor(4.0%~ %) carbon dioxide(0.0365%) methane( %), hydrogen( %) nitrous oxide( %), CO( %) ozone( %), Fluorocarbon12( %) 10

11 Target of open-path path monitoring (2) Air pollution substances measurable effect man, animals, vegetation, or materials Substances: natural or anthropogenic (man-made) chemical compounds gases, liquid drops, or solid particles. Criteria pollutants at surface (defined by EPA): Ozone Carbon monoxide. Sulfur dioxide Nitrogen oxides Lead Particulates 11

12 Target of open-path path monitoring (3) Atmospheric monitoring 원격측정에이용 : 위성, 항공기, Spectral resolution nm between 240 und 790 nm In addition to Ozone several other trace gases can be measured NO2 BrO OClO HCHO SO2 H2O O2 O4 12

13 진행연구 UV-DOAS 방법을이용한가스의흡수단면적측정 UV-DOAS 방법을이용한대기중배경가스농도의측정 UV-DOAS 방법을이용한 SOURCE monitoring 및 3D tomography Spectrometer 를이용한에어로졸측정 FTIR 을이용한 IR 가스흡수단면적측정 FTIR 을이용한대기미량가스조성분석 FTIR을이용한대기중화학물질감지및 tomography 13

14 연구결과 (UV-DOAS) 가스의흡수단면적측정 Spectrometer (JY) 흡수단면적 Estimated uncertainties of two absorption cross section measurements (Benzene) Uncertainty factors Light path length Pressure Temperature Uncertainty of CRM (C 6 H 6 ) Stability of light source Absorbance Total Relative uncertainty[±1σ: %] ( nm)

15 연구결과 (UV-DOAS) 대기중배경가스농도의측정 Spectrometer (320) LP-DOAS Detection limit 측정예 Species NO 2 SO 2 O 3 HNO 2 HCHO DL (ppbv) Rel. Unc [%] Concentration [ppbv] L.I(counts) O Light Intensity HONO NO 2 SO date

16 Spectrometer 를이용한에어로졸측정 Extinction 측정 : 대기중입자광학적 / 물리적특성예측 16

17 연구결과 (FTIR) 가스의흡수단면적측정 FTIR (120HR, Bruker), MIR LDL: /cm Estimated uncertainties of two absorption cross section measurements (NF 3 ) Absorption cross section [10-19 cm 2 ] Resoluti on [cm -1 ] Abs White cell 압력 (bar) (1) cm (2) cm (3) cm Relative unc.(std): 3.5 % 17

18 연구결과 (FTIR) MIR 배경가스조성및온실가스측정 안면도배경가스 Cell 샘플측정예 ( 제조공기 ; CH 4 : ppm, CO 2 : ppm) CO2: ppm (2.61, 1.15%) CH4: ppb (55.32, 0.07%) 18

19 가스측정시스템 HR-FTIR (BRUKER, 분해능 : cm -1 ) OP-DOAS ( 제작, UV spectra) HR-monochrometer (J-Y, 분해능 : 0.1 A 이하 ) retro-reflector array 19

20 가스측정시스템 정밀한가스측정을위하여그림과같이자동화된가스측정장치의구축이필요합니다. waste flow control ~400 ml/min T p sample flow White cell 6.4 m path 750 ml vol. IR source purge gas:zero air flow: ~5 L/min dewpoint: ~-75 C MCT- High D* dectector LN 2 cooled range: cm -1 Interferometer KBr beamsplitter 20