1、PD CEN/TS 16976:2016 Ambient air Determination of the particle number concentration of atmospheric aerosol BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06PD CEN/TS 16976:2016 PUBLISHED DOCUMENT National foreword This Published Document is the UK implementation of C
2、EN/TS 16976:2016. The UK participation in its preparation was entrusted to Technical Committee EH/2/3, Ambient atmospheres. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of
3、a contract. Users are responsible for its correct application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 978 0 580 90926 9 ICS 13.040.20 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published
4、under the authority of the Standards Policy and Strategy Committee on 31 August 2016. Amendments/corrigenda issued since publication Date 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
5、Version Ambient air - Determination 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 Specificatio
6、n (CEN/TS) was approved by 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
7、a European Standard. CEN 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
8、the final decision about 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, Icel
9、and, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Manag
10、ement Centre: Avenue Marnix 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 16976:2016 CEN/TS 16976:2016 (E) 2 Contents Page European Foreword 5 Introduction 6 1 Scope 7 2 Normativ
11、e references 7 3 Terms and 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 1
12、3 6 CPC performance criteria 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 Numb
13、er concentration detection 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
14、 temperature and pressure sensor 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 hum
15、idity . 19 7.5 Dilution factor . 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 16976:2016 CEN/TS 16976:2016 (E) 3 8.5 Data processing and reporti
16、ng 21 9 Quality control, quality 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
17、.2.5 CPC zero check . 22 9.2.6 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
18、) . 23 9.2.13 Leak check . 23 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 .
19、 25 9.3.7 Dilution factor (where 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
20、 . 29 B.2 Air properties and 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
21、 (data processed to final physical 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.
22、6 Line-by-line explanations: . 35 Annex D (informative) Uncertainty calculation (example) 47 D.1 General 47 D.2 CPC plateau detection efficiency . 47 PD CEN/TS 16976:2016 CEN/TS 16976:2016 (E) 4 D.3 CPC detection efficiency drift . 47 D.4 Flow determination . 47 D.5 Correction to standard temperatur
23、e and pressure . 47 D.6 Sampling 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 (inform
24、ative) Dilution systems . 53 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
25、 PD CEN/TS 16976:2016 CEN/TS 16976:2016 (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 su
26、bject of patent rights. CEN shall 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,
27、Croatia, Cyprus, Czech Republic, 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 a
28、nd the United Kingdom. PD CEN/TS 16976:2016 CEN/TS 16976:2016 (E) 6 Introduction There is a growing awareness of the significance of aerosol particles with diameters of D 1 m for human health as well as for their climatic impact. To assess air quality, it appears necessary to supplement gravimetrica
29、lly determined mass concentrations such as PM 10 or PM 2.5 with a measurement of the particle number concentration. Since ultrafine particles with diameters of D 0,1 m make an almost insignificant contribution to the mass of atmospheric aerosol particles, they can best be detected with counting meas
30、uring methods of sufficient sensitivity. As particle measurement instrumentation allows determining either the particle number concentration or the particle number size distribution two Technical Specifications will be established: one dealing with the determination of the single parameter number co
31、ncentration (a measure of “total” number concentration), one dealing with the determination of number concentration within a limited number of size ranges. Clauses 5 and 6 contain general information about the method and the expected properties of the aerosol to be measured. Clause 7 sets out the pe
32、rformance criteria for CPCs. Specifically, these are the relevant performance characteristics of CPC instruments (without any sampling system), the respective criteria that shall be met, and a description of how the tests shall be carried out. In general these tests are expected to be carried out by
33、 test houses or CPC manufacturers rather than users, and could form the basis for type testing of CPCs in future. Clause 8 sets out the performance criteria and test procedures for the sampling and conditioning system (e.g. dilution). These may be applied by manufacturers of sampling systems, test h
34、ouses or users (network operators). Clause 9 sets out requirements for the installation, initial checks and calibrations, and operation of a CPC and sampling system at a monitoring site, including routine maintenance, data processing (including use of QA/QC data) and reporting. In general these will
35、 be the responsibility of users (network operators), though calibrations requiring test aerosols shall only be carried out by suitably qualified laboratories. Clause 10 sets out Quality Assurance and Quality Control procedures, i.e. the ongoing checks and calibrations that are required on the CPC an
36、d sampling system during operation at a monitoring site. It is expected that these will be the responsibility of users (network operators), though calibrations requiring test aerosols shall only be carried out by suitably qualified laboratories. The main sources of measurement uncertainty are descri
37、bed. PD CEN/TS 16976:2016 CEN/TS 16976:2016 (E) 7 1 Scope This Technical Specification describes a standard method for determining the particle number concentration in ambient air in a range up to about 10 7cm 3for averaging times equal to or larger than 1 min. The standard method is based on a Cond
38、ensation Particle Counter (CPC) operated in the counting mode and an appropriate dilution system for concentrations exceeding the counting mode range. It also defines the performance characteristics and the minimum requirements of the instruments to be used. The lower and upper sizes considered with
39、in this document are 7 nm and a few micrometres, respectively. This document describes sampling, operation, data processing and QA/QC procedures including calibration parameters. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are
40、indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 27891, Aerosol particle number concentration Calibration of condensation particle counters 3 Terms an
41、d definitions For the purposes of this document, the following terms and definitions apply. 3.1 actual flow rate volumetric flow rate of an individual instrument, measured at its inlet under the actual air conditions 3.2 aerosol a multi-phase system of solid and/or liquid particles suspended in a ga
42、s, ranging in particle size from 0,001 m to 100 m 3.3 calculation flow rate flow rate which directly relates count rate and particle number concentration Note 1 to entry: This flow rate is used for instrument internal calculation of the particle number concentration. It depends on the instrument typ
43、e and may be nominal, factory-certified or actual inlet flow rate. It may also include a calibration factor unless the total inlet flow is analysed. 3.4 coincidence error error that occurs with counting measuring methods when two or more particles are counted simultaneously as a single particle Note
44、 1 to entry: Coincidence error is related to particle number concentration, flow velocity through the sensing zone and size of sensing zone. PD CEN/TS 16976:2016 CEN/TS 16976:2016 (E) 8 3.5 detection efficiency ratio of the particle number concentration determined by the measuring instrument to the
45、reference particle number concentration of the aerosol at the instruments inlet Note 1 to entry: The detection efficiency depends on particle size and may depend on particle number concentration. 3.6 factory-certified flow rate volumetric flow rate of an individual instrument at the time of factory
46、calibration, measured at its inlet under the actual air conditions, and documented on a check out certificate 3.7 nominal flow rate volumetric flow rate indicated on the instrument specification sheet by the manufacturer Note 1 to entry: The nominal flow rate is that flow rate, which a specific CPC
47、model is designed for by the manufacturer. The real flow rate of individual instruments may differ from the nominal flow due to manufacturing tolerances. 3.8 number size distribution frequency distribution of the particle number concentration represented as a function of particle size 3.9 particle s
48、mall piece of matter with defined physical boundary Note 1 to entry: The phase of a particle can be solid, liquid, or between solid and liquid and a mixture of any of the phases. SOURCE: ISO 27891:2015, modified 3.10 particle number concentration number of particles related to the unit volume of the
49、 carrier gas Note 1 to entry: For the exact particle number concentration indication, information on the gaseous condition (temperature and pressure) or the reference to a standard volume indication is necessary. SOURCE: ISO 27891:2015 4 Atmospheric aerosol Atmospheric aerosols are strongly dependent on their local and regional sources. Especially, the size distribution in number and mass, as well as the size-resolved chemical composition are highly variable. Aerosol particles are either emitted directly (primary aerosols) or formed by nucleation and condensati
