CEN TS 16976-2016 Ambient air - Determination of the particle number concentration of atmospheric aerosol《环境空气-大气气溶胶粒子数浓度的测定》.pdf

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1、PD CEN/TS 16976:2016Ambient air Determinationof the particle numberconcentration of atmosphericaerosolBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06PD CEN/TS 16976:2016 PUBLISHED DOCUMENTNational forewordThis Published Document is the UK implementation of CEN/TS169

2、76:2016.The UK participation in its preparation was entrusted to TechnicalCommittee EH/2/3, Ambient atmospheres.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Use

3、rs are responsible for its correctapplication. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 90926 9ICS 13.040.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This Published Document was published under the authority of

4、 theStandards Policy and Strategy Committee on 31 August 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dPD CEN/TS 16976:2016TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION CEN/TS 16976 August 2016 ICS 13.040.20 English Version Ambient air - Det

5、ermination of the particle number concentration of atmospheric aerosol Air ambiant - Dtermination de la concentration en nombre de particules de larosol atmosphrique Auenluft - Bestimmung der Partikelanzahlkonzentration des atmosphrischen Aerosols This Technical Specification (CEN/TS) was approved b

6、y CEN on 26 June 2016 for provisional application. The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard. CEN

7、members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final decision about

8、the possible conversion of the CEN/TS into an EN is reached. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latv

9、ia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marni

10、x 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TS 16976:2016 EPD CEN/TS 16976:2016CEN/TS 16976:2016 (E) 2 Contents Page European Foreword 5 Introduction 6 1 Scope 7 2 Normative references 7 3 Terms and

11、definitions . 7 4 Atmospheric aerosol 8 5 Description of the method . 9 5.1 Sampling and conditioning 9 5.1.1 Sampling . 9 5.1.2 Drying . 10 5.1.3 Dilution 11 5.2 Determination of the number concentration with a CPC 11 5.2.1 Condensation growth 11 5.2.2 Optical detection 13 6 CPC performance criteri

12、a and test procedures . 14 6.1 General . 14 6.2 General requirements of the CPC . 14 6.3 Test conditions 15 6.4 Performance characteristics and criteria . 15 6.5 Test procedures 16 6.5.1 Inlet flow rate accuracy 16 6.5.2 Number concentration measurement range 16 6.5.3 Number concentration detection

13、limit . 16 6.5.4 Linearity and slope of response 16 6.5.5 Detection efficiency curve at low particle size 17 6.5.6 Upper particle size detection limit 17 6.5.7 Zero count rate 17 6.5.8 Response time . 17 6.5.9 Dependence of flow rate on supply voltage 17 6.5.10 Accuracy of temperature and pressure s

14、ensor calibration 18 6.5.11 Effect of failure of mains voltage 18 7 Performance criteria and test procedures for the sampling and conditioning system 18 7.1 General requirements 18 7.2 Performance characteristics and criteria . 18 7.3 Diffusion losses . 19 7.4 Relative humidity . 19 7.5 Dilution fac

15、tor . 19 7.6 Primary sampling flow . 19 8 Measurement procedure . 20 8.1 Measurement planning 20 8.2 Environmental operating conditions 20 8.3 Initial installation 20 8.4 Initial checks on site 20 PD CEN/TS 16976:2016CEN/TS 16976:2016 (E) 3 8.5 Data processing and reporting 21 9 Quality control, qua

16、lity assurance and measurement uncertainty 21 9.1 General 21 9.2 Frequency of calibrations, checks and maintenance . 21 9.2.1 General 21 9.2.2 Maintenance of CPC 22 9.2.3 Calibration of CPC plateau region and linearity 22 9.2.4 Determination of CPC low size cut-off . 22 9.2.5 CPC zero check . 22 9.2

17、.6 Number concentration check . 23 9.2.7 CPC flow rate calibration 23 9.2.8 Temperature and pressure sensor calibration 23 9.2.9 CPC internal diagnostics . 23 9.2.10 Sample system maintenance 23 9.2.11 Relative humidity sensor . 23 9.2.12 Dilution factor (where applicable) . 23 9.2.13 Leak check . 2

18、3 9.3 Measurement uncertainty . 24 9.3.1 General 24 9.3.2 CPC plateau detection efficiency . 24 9.3.3 CPC detection efficiency drift 24 9.3.4 Flow determination . 25 9.3.5 Correction to standard temperature and pressure 25 9.3.6 Sampling losses due to diffusion to walls . 25 9.3.7 Dilution factor (w

19、here applicable) . 25 9.3.8 Calculation of overall uncertainty 25 Annex A (normative) Determination of diffusion losses in sampling lines 27 Annex B (informative) Example of the calculation of diffusion losses in a sampling system 29 B.1 Description of the sampling system . 29 B.2 Air properties and

20、 diffusion coefficient . 30 B.3 Losses in the primary sampling tube . 30 B.4 Losses in the secondary sampling tube and the dryer 31 B.5 Overall sampling losses 31 Annex C (informative) Data reporting 32 C.1 Motivation . 32 C.2 Level 0 (annotated raw data) . 32 C.3 Level 1 (data processed to final ph

21、ysical property, potential corrections applied, original temporal resolution) . 33 C.4 Level 2 (hourly averages, including measures of variability) 33 C.5 GAW WDCA Condensation Particle Counter Level 0 (raw data) file format example (system without sample dilution): 35 C.6 Line-by-line explanations:

22、 . 35 Annex D (informative) Uncertainty calculation (example) 47 D.1 General 47 D.2 CPC plateau detection efficiency . 47 PD CEN/TS 16976:2016CEN/TS 16976:2016 (E) 4 D.3 CPC detection efficiency drift . 47 D.4 Flow determination . 47 D.5 Correction to standard temperature and pressure . 47 D.6 Sampl

23、ing losses due to diffusion to walls 47 D.7 Dilution factor (where applicable) 48 D.8 Calculation of overall uncertainty 48 Annex E (informative) Atmospheric aerosols in Europe 49 E.1 General . 49 E.2 Mean concentrations 49 E.3 Examples of measurements 50 Annex F (informative) Dilution systems . 53

24、F.1 Background 53 F.2 Criteria for dilution systems 53 F.3 Operation principles of dilution systems 53 F.3.1 General . 53 F.3.2 Dilution systems with partial flow filtration 54 F.3.3 Dilution systems with external clean air supply 54 Annex G (informative) Laminar flow 56 PD CEN/TS 16976:2016CEN/TS 1

25、6976:2016 (E) 5 European Foreword This document (CEN/TS 16976:2016) has been prepared by Technical Committee CEN/TC 264 “Air quality”, the secretariat of which is held by DIN. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN sh

26、all not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republi

27、c, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. PD CEN/

28、TS 16976:2016CEN/TS 16976:2016 (E) 6 Introduction There is a growing awareness of the significance of aerosol particles with diameters of D 95 % at (50 10) nm 6.5.4 7 Upper particle size detection limit 90 % detection efficiency at 1000 nm 100 nm 6.5.6 PD CEN/TS 16976:2016CEN/TS 16976:2016 (E) 16 8

29、Zero count rate 0,5. Determine D50by linear interpolation. The result is accepted if 6,3 nm D50 7,7 nm. Measure the CPC detection efficiency at 14 nm. The result is accepted if (14 nm) 0,9. If any of the results is not accepted, further maintenance is required. 9.2.5 CPC zero check If a dryer or a d

30、ilution system is used, these devices shall be included in this zero check. Attach an ULPA filter either to the inlet of the CPC or to the inlet of the dryer or the dilution system. Run the CPC for at least 5 min to purge the filter and the CPC. Run the CPC for a minimum of 15 min. The zero count ra

31、te during this period shall be less than 15 counts per minute. If not, maintenance is required. PD CEN/TS 16976:2016CEN/TS 16976:2016 (E) 23 9.2.6 Number concentration check A check on the performance of the CPC shall be carried out every 3 months. This can be less rigorous than the annual calibrati

32、on, for example taking the form of a field comparison using a recently calibrated reference CPC connected to the secondary sampling tube via a Y-shaped connector. If the hourly average concentration determined by the field CPC deviates by more than 10 % from the reference, maintenance is required. 9

33、.2.7 CPC flow rate calibration Run a test similar to the one in 6.5.1, but only at ambient temperature and pressure: At least 5 consecutive measurements shall be taken over a minimum period of 5 min. The mean of the measurement results shall be compared with the flow rate as specified by the manufac

34、turer, and the relative difference shall meet the criteria for the actual flow rate in Table 1 (difference 5 % to the nominal flow rate, difference 2 % to the factory-certified flow rate). If these criteria are not met, maintenance is required. The result of the calibration shall be documented and u

35、sed for further number concentration calculations or included in the calibration factor for correction. 9.2.8 Temperature and pressure sensor calibration The temperature and pressure sensors used to correct sampled volumes to standard temperature and pressure shall be calibrated by any appropriate m

36、ethod to confirm that the values are correct to within 3 K for temperature and 1 kPa for pressure. 9.2.9 CPC internal diagnostics Internal diagnostics, especially warning and error flags, shall be checked at least weekly in case of remote data access, otherwise monthly. Users shall develop procedure

37、s appropriate to their systems. For example, if data availability over last 7 days is less than 99 %, the error flags can be checked for recorded errors. Corrective action shall be taken if necessary (e.g. CPC maintenance). 9.2.10 Sample system maintenance The sampling system shall be maintained acc

38、ording to the manufacturers instructions. 9.2.11 Relative humidity sensor The relative humidity sensor in the sampling system shall be calibrated by any appropriate method to confirm that the relative humidity values between 20 % and 80 % are correct to within 3 %. 9.2.12 Dilution factor (where appl

39、icable) If the sampling system includes dilution, the dilution factor shall be determined using one of the methods described in 7.5, and shall show agreement with the previously determined value to within 5 %. If the deviation is greater than 5 %, maintenance is required. 9.2.13 Leak check Put an UL

40、PA filter on the inlet to the system or via an optional three-way valve (see Figure B.1). Purge the system for at least 5 min. Leakage within the sampling system shall be checked for a minimum of 15 min. The zero count rate during this period shall be less than 15 counts per minute. This test includ

41、es the CPC zero count rate check according to 9.2.5, which, if this test is passed, does not need to be performed separately. Maintenance of the sampling system is required if the CPC zero count rate check is then passed. PD CEN/TS 16976:2016CEN/TS 16976:2016 (E) 24 9.3 Measurement uncertainty 9.3.1

42、 General The main components of the measurement uncertainty for one-minute-duration measurements are set out in Table 5. In practice, random noise is only significant for very low particle concentrations, and so the uncertainty for measurements averaged over a longer period will be similar. Table 5

43、Uncertainty components and how to estimate them Uncertainty component Symbol Clause Estimation CPC plateau detection efficiency u9.3.2 As given on CPC calibration certificate CPC detection efficiency drift udrift9.3.3 From analysis of stability between calibrations Flow determination uflow9.3.4 From

44、 uncertainty of flow calibration, and long term stability Correction of volume to standard temperature and pressure uSTP9.3.5 From uncertainty of T and p measurements Sampling losses due to diffusion to walls uloss9.3.6 A fixed value estimated theoretically Dilution factor (where appropriate) udil9.

45、3.7 From the uncertainty of the method used to determine the dilution factor, and from the stability of these determinations. Many other factors will contribute to the uncertainty, but are here considered to be negligible. For example: CPC nonlinearity this will be much more significant if the photo

46、metric mode is used; CPC low size cut-off the effect will be highly dependent on the particle size distribution, but is generally small; Effect of hygroscopic growth the growth of particles in the sampling system, even after control of relative humidity, will have some effect on the size distributio

47、n, but only a negligible effect on the total numbers, in effect by altering the low size cut-off; Repeatability as noted above, random noise is only significant for very low particle concentrations; Leakage with the criteria specified, the contribution of leakage to the uncertainty will be very smal

48、l. 9.3.2 CPC plateau detection efficiency Following ISO 27891, the annual calibration of the CPC will lead to a certificate that includes a value for the uncertainty in the detection efficiency determination. The component uis the 1 value, so that if the uncertainty is presented as k = 2 or 95 % con

49、fidence,uis half this value. The component shall be expressed as a percentage of the detection efficiency. 9.3.3 CPC detection efficiency drift The CPC detection efficiency drift is estimated from the typical difference between the “post maintenance” and subsequent “as found” detection efficiencies, diff. PD CEN/TS 16976:2016CEN/TS 16976:2016 (E) 25 Calculate the mean of these differences,diff . For the purposes of this Technical Specification, the uncertainty component drift diff100 / 2u = where is the mean post maint