1、February 2009DEUTSCHE NORM English price group 24No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 13.040.20!$V) Fundame
2、ntals VDI 4212 Blatt 1, Remote sensing Atmospheric measurements near ground with DOAS Gaseous emissions and ambient air measurements Fundamentals EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15483November 2008ICS 13.040.20English VersionAmbient air quality - Atmospheric measurements near ground
3、with FTIR spectroscopyQualit de lair ambiant - Mesurages de lair ambiant proximit du sol par spectroscopie transforme deFourier (FTIR)Luftqualitt - Messungen in der bodennahen Atmosphremit FTIR-SpektroskopieThis European Standard was approved by CEN on 11 October 2008.CEN members are bound to comply
4、 with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management
5、Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theoffici
6、al versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Sloveni
7、a, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN nationa
8、l Members.Ref. No. EN 15483:2008: EEN 15483:2008 (E) 2 Contents Page Foreword3 Introduction .3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Symbols and abbreviations 5 5 Principle6 6 Measurement planning10 7 Measurement procedure .12 8 Calibration and quality assurance .15 9 Data
9、processing.20 10 Sources of uncertainty24 11 Servicing.27 Annex A (informative) The classical Fourier transform spectrometer 28 Annex B (informative) Monitoring configurations .33 Annex C (informative) Equipment35 Annex D (informative) Conditions for measuring emission flux 39 Annex E (informative)
10、Servicing 40 Annex F (normative) Performance characteristics42 Annex G (informative) Influence of fog on the spectra .46 Annex H (informative) Sample form for a measurement record.49 Annex I (informative) Calibration by using spectral lines from databases and determination of the instrument line sha
11、pe (example)54 Annex J (informative) Example applications56 Bibliography 67 DIN EN 15483:2009-02 EN 15483:2008 (E) 3 Foreword This document (EN 15483:2008) has been prepared by Technical Committee CEN/TC 264 “Air quality”, the secretariat of which is held by DIN. This European Standard shall be give
12、n the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2009, and conflicting national standards shall be withdrawn at the latest by May 2009. Attention is drawn to the possibility that some of the elements of this document may be the s
13、ubject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium,
14、 Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Introduction Fourier t
15、ransform infrared spectroscopy (FTIR spectroscopy) has been successfully developed from an established laboratory analytical method to a versatile remote sensing method for atmospheric gases. In this method, the long-path absorption of IR radiation by gaseous air pollutants is measured over an open
16、path between an artificial IR source and an IR spectrometer and used to calculate the integrated concentration over the monitoring path. Since IR radiation is used for remote sensing, the measurements can be made without contact, that is to say without direct sampling, and can be made in various dir
17、ections. These measurements include monitoring diffuse emissions from large-area sources, for example landfills, road traffic routes, sewage treatment plants, areas used for industrial or agricultural purposes, and in addition the minimization of production losses by tracing leaks in plant sections
18、or piping systems. FTIR spectroscopy is thus suitable for a great number of analytical tasks which cannot adequately be performed using in-situ methods that make point measurements. Generally, using a suitable measuring arrangement, an overview of the local air pollution may be obtained on site in a
19、 short time. This also includes measurements in areas to which access is difficult or impossible, or where the direct presence of staff or set-up of instruments is dangerous. FTIR spectroscopy can be used to determine different compounds at the same time. This European Standard presents the function
20、 and performance of FTIR analytical systems. At the same time, operational notes are given, so that reproducible and valid measurements can be obtained. In addition, questions of measurement planning are discussed and the appendices give a selection of typical applications. In some circumstances (e.
21、 g. CO) the method might be applicable for measurement of air quality as required by European legislation 1. DIN EN 15483:2009-02 EN 15483:2008 (E) 4 1 Scope This European Standard is applicable to open-path absorption measurements of concentration path length product using the Fourier transform inf
22、rared (FTIR) technique with an artificial radiation source. It is applicable to the continuous measurement of infrared active organic and inorganic compounds in the gaseous state in ambient air using fixed tropospheric open paths up to approximately 1 km in length and provides a spatial average. 2 N
23、ormative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 6142, Gas analysis - P
24、reparation of calibration gas mixtures - Gravimetric method (ISO 6142:2001) EN ISO 6144, Gas analysis - Preparation of calibration gas mixtures - Static volumetric method (ISO 6144:2003) EN ISO 9169, Air quality - Definition and determination of performance characteristics of an automatic measuring
25、system (ISO 9169:2006) ISO 6145 (all parts), Gas analysis Preparation of calibration gas mixtures using dynamic volumetric methods 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 absorbance the negative logarithm of the transmission, )(/)(lg(
26、)( 0IIA = , where I() is the spectral transmitted intensity of the radiation and )(0I is the incident spectral intensity NOTE 10loglg = 3.2 apodisation application of a weighting function to interferogram data to alter the instruments response function 3.3 background spectrum with all other conditio
27、ns being equal, that spectrum taken in the absence of the particular absorbing species of interest 3.4 instrument line shape (ILS) mathematical function which describes the effect of the instruments response on a monochromatic line. 3.5 intensity radiant power per unit solid angle (non-collimated be
28、am) or per unit area (collimated beam) 3.6 interferogram effects of interference that are detected and recorded by a two-beam interferometer DIN EN 15483:2009-02 EN 15483:2008 (E) 5 3.7 interferogram acquisition time time to acquire a single interferogram 3.8 monitoring path actual path in space ove
29、r which the pollutant concentration is measured and averaged 3.9 open-path measurement measurement which is performed in the open atmosphere 3.10 path length distance that the radiation travels in the open atmosphere 3.11 reference spectrum spectrum of the absorbance versus wavenumber for a pure gas
30、eous sample under defined measurement conditions and known and traceable concentrations 3.12 signal-to-noise ratio ratio between the signal strength and the RMS (root mean square) noise 3.13 spectral acquisition time time to acquire and co-add interferograms to achieve required signal-to-noise ratio
31、, including the Fourier transform processing 3.14 spectral intensity radiant power per unit solid angle per wave number (non-collimated beam) or per unit area per wave number (collimated beam) 3.15 synthetic background spectrum spectrum that is derived from a field spectrum by choosing points along
32、the baseline and connecting them with a high-order polynomial or short, straight lines 4 Symbols and abbreviations a() specific (decadic) absorption coefficient; ai() specific (decadic) absorption coefficient of the ith compound; a()IVspecific absorption coefficient of the interfering variable; a()M
33、Vspecific absorption coefficient of the measured variable; a() specific (natural) absorption coefficient (=a()/lg(e); c concentration; ciconcentration of the ith compound; DIN EN 15483:2009-02 EN 15483:2008 (E) 6 cIVconcentration of the interfering variable; cMVconcentration of the measured variable
34、; I() spectral intensity incident on the receiver (also abbreviated I); I0() spectral intensity of radiation emitted by the transmitter (also abbreviated to I0); IV index for interfering variable; l length of the monitoring path; MV index for measured variable ; n number of measured values; wave num
35、ber in cm1; unapodised spectral resolution; smaxmaximum optical path difference; standard deviation; t student factor (for a statistical confidence of 95%). 5 Principle 5.1 General In infrared (IR) absorption spectroscopy, IR radiation is passed through a sample to a detector and the detected radiat
36、ion is analysed to determine the spectral intensity which is received. Comparison of the transmitted intensity versus non-attenuated intensity shows at which wavelengths species present in the sample have absorbed radiation. Absorption takes place as a result of rotational and vibrational excitation
37、 of the absorbing species, and the wavelengths at which the radiation is absorbed are therefore characteristic of the molecular structure. The infrared absorption spectrum is therefore able to provide a basis for identification and quantification of the absorbing species present. For further informa
38、tion on the fundamental principles of IR spectroscopy, a number of suitable texts are available e. g. 2; 3. The FTIR technique measures the interferogram, for example using the Michelson interferometer technique, of the broadband IR radiation intensity. By performing a Fourier transform of this inte
39、rferogram across a wide range of wavelengths a spectrum is obtained containing information about the absorption features of gases within the monitoring path. In principle it is then possible to analyse these absorption features to determine the total concentration of a wide range of species. The FTI
40、R system is capable of making simultaneous measurements of multiple species. 5.2 Configuration of the measurement system Open-path techniques measure the concentration path length product of one or more species in the atmosphere within a defined, extended optical path. The total concentration of the
41、 species is derived from this measurement value. Two of the basic configurations for an open-path monitoring system are given in Figures 1 and 2 4. DIN EN 15483:2009-02 EN 15483:2008 (E) 7 In the bistatic system (Figure 1) the transmitter and the detector are separated at the two ends of the optical
42、 beam. The monostatic system (Figure 2) operates by transmitting the optical beam into the atmosphere to a passive retroreflector which returns the beam to the detector. DIN EN 15483:2009-02 EN 15483:2008 (E) 8 Key 1 FTIR spectrometer 2 telescope for radiation collection 3 ambient air 4 monitoring p
43、ath 5 IR radiation source with collimating optics Figure 1 Bistatic arrangement for FTIR remote sensing Key 1 FTIR spectrometer 2 telescope for radiation collection 3 ambient air 4 monitoring path 5 IR radiation source with collimating optics 6 FTIR spectrometer including radiation source 7 telescop
44、e for transmission and collection of IR radiation 8 retroreflector Figure 2 Monostatic arrangement for FTIR remote sensing In the bistatic measurement set-up, the IR radiation source (5) and the FTIR spectrometer (1) are spatially separated from one another. The two instrumental parts are oriented i
45、n such a way that the radiation emitted from the IR source and collimated by a parabolic mirror is collected by the FTIR spectrometer telescope (2). The monitoring path length is defined by the distance between collimating and receiving optics. For a monostatic measurement set-up, transmitting and r
46、eceiving optics are an integral part of the FTIR spectrometer (6), which also includes the IR radiation source and a beam splitter serving to separate the received and transmitted beams. By means of a retroreflector (8) the IR beam passes twice through the DIN EN 15483:2009-02 EN 15483:2008 (E) 9 me
47、asurement volume. The monitoring path length in this case is defined by twice the distance between the transmitter/receiver and the retroreflector optics. Monostatic systems have the advantage that the transmitted radiation can be modulated to reduce the effect of background emission interference. 5
48、.3 The Beer-Lambert law The basis for the quantitative evaluation of transmission measurements for the determination of concentrations of gases is the Beer-Lambert law. This relates the frequency-specific absorption of the emitted infrared radiation by the gases present in the monitoring path betwee
49、n source and FTIR spectrometer and their concentrations. The Beer-Lambert law, for the special case of only one absorbing gas mixed homogeneously in the monitoring path has the following form: )lc)(a(e)(I)(I=0(1) With the relationship )(a)e()(a = lg the following applies )(010)()()(lcaIIT= (2) where T )( transmittance; I0() intensity of radiation emitted by the transmitter (also abbreviated to I0below); I() intensity incident on the receiver (also termed I below); a() spe
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