Ambient air quality - Standard method for the measurement of the concentration of ozone by ultraviolet photometry

This document specifies a continuous measurement method for the determination of the concentration of ozone present in ambient air based on the ultraviolet photometric measuring principle. This document describes the performance characteristics, and sets the relevant minimum criteria required to select an appropriate ultraviolet photometric ozone analyser by means of type approval tests. It also includes the evaluation of the suitability of an anayser for use in a specific fixed site so as to meet the Directives data quality requirements and requirements during sampling, calibration and quality assurance.
The method is applicable to the determination of the mass concentration of ozone present in ambient air in the range from 0 mg/m3 to 500 mg/m3. This concentration range represents the certification range for the type approval test.
NOTE 1   0 mg/m3 to 500 mg/m3 of O3 corresponds to 0 nmol/mol to 250 nmol/mol of O3.
The method covers the determination of ambient air concentrations of ozone in zones classified as rural areas, urban and urban-background areas.
NOTE 2   Other ranges may be used for measurement systems applied at rural locations monitoring Ecosystems.
The results are expressed in mg/m3 (at 20 °C and 101,3 kPa).
When the standard is used for other purposes than the EU-directive, the range and uncertainty requirements need not apply.

Luftqualität - Messverfahren zur Bestimmung der Konzentration von Ozon mit Ultraviolett-Photometrie

Dieses Dokument legt ein kontinuierliches Messverfahren zur Bestimmung der Konzentration von Ozon in Luft nach dem Ultraviolett-Photometrie-Messprinzip fest. Dieses Dokument gibt die Leistungskenngrößen an und legt die relevanten Mindestanforderungen für die Eignungsprüfung von Ultraviolett-Photometern fest. Es schließt auch die Bewertung der Eignung eines Messgeräts zur Anwendung an einer spezifischen Messstelle hinsichtlich der Anforderungen der EU-Richtlinien an die Datenqualität und hinsichtlich der Anforderungen für Probenahme, Kalibrierung und Qualitätssicherung ein.
Das Verfahren ist anwendbar zur Bestimmung der Massenkonzentration von Ozon in Luft im Bereich von 0 µg/m³ bis 500 µg/m³. Dieser Konzentrationsbereich entspricht dem Zertifizierungsbereich für die Eignungsprüfung.
ANMERKUNG 1   0 µg/m3 bis 500 µg/m3 O3 entspricht 0 nmol/mol bis 250 nmol/mol O3.
Das Verfahren umfasst die Bestimmung der Konzentration von Ozon in Gebieten, die als ländliche Gebiete, städtische Gebiete und Gebiete mit städtischem Hintergrund klassifiziert sind.
ANMERKUNG 2   Für Messsysteme an ländlichen Standorten zur Überwachung von Ökosystemen können kleinere Messbereiche verwendet werden.
Die Ergebnisse werden in µg/m³ (bei 293 K und 101,3 kPa) angegeben.
Wenn diese Norm für andere als in der EU-Richtlinie festgelegte Zwecke eingesetzt wird, brauchen die Anforderungen hinsichtlich Anwendungsbereich und Unsicherheit nicht zur Geltung kommen.

Qualité de l'air ambiant - Méthode normalisée pour le mesurage de la concentration en ozone par photométrie U.V.

Le présent document spécifie une méthode de mesurage en continu pour la détermination de la concentration en ozone de l'air ambiant. Cette méthode est basée sur le principe de mesure par photométrie U.V. Le présent document décrit les caractéristiques de performance et fixe les critères minimums requis pour sélectionner un analyseur par photométrie U.V. approprié à l'aide d'essais d'approbation de type. Il présente également l'évaluation de l'aptitude à l'emploi d'un analyseur sur un site fixe spécifique de manière à répondre aux exigences de qualité des données prescrites dans les Directives ainsi qu'aux exigences à observer au cours du prélèvement, de l'étalonnage et de l'assurance qualité.
La méthode s'applique à la détermination de la concentration massique en ozone présent dans l'air ambiant dans la plage allant de 0 mg/m3 à 500 mg/m3. Cette plage de concentration représente l'étendue de mesure certifiée pour l'essai d'approbation de type.
NOTE 1   0 µg/m3 à 500 mg/m3 d'O3 correspondent à 0 nmol/mol à 250 nmol/mol d'O3.
La méthode couvre la détermination des concentrations en ozone présent dans l'air ambiant dans les zones classées comme zones rurales, urbaines et périurbaines.
NOTE 2   D'autres plages peuvent être utilisées pour les systèmes de mesure appliqués aux zones rurales contrôlant des écosystèmes.
Les résultats sont exprimés en mg/m3 (à 20 °C et 101,3 kPa).
Lorsque la norme est utilisée à d'autres fins que la Directive UE, les exigences relatives à la plage et à l'incertitude peuvent ne pas être appliquées.

Kakovost zunanjega zraka – Standardna metoda za določanje koncentracije ozona z ultravijolično fotometrijo

General Information

Status
Withdrawn
Publication Date
08-Mar-2005
Withdrawal Date
21-Aug-2012
Current Stage
9960 - Withdrawal effective - Withdrawal
Due Date
22-Aug-2012
Completion Date
22-Aug-2012

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SLOVENSKI STANDARD
SIST EN 14625:2005
01-september-2005
.DNRYRVW]XQDQMHJD]UDND±6WDQGDUGQDPHWRGD]DGRORþDQMHNRQFHQWUDFLMHR]RQD
]XOWUDYLMROLþQRIRWRPHWULMR

Ambient air quality - Standard method for the measurement of the concentration of

ozone by ultraviolet photometry

Luftqualität - Messverfahren zur Bestimmung der Konzentration von Ozon mit Ultraviolett

-Photometrie

Qualité de l'air ambiant - Méthode normalisée pour le mesurage de la concentration en

ozone par photométrie U.V.
Ta slovenski standard je istoveten z: EN 14625:2005
ICS:
13.040.20 Kakovost okoljskega zraka Ambient atmospheres
SIST EN 14625:2005 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 14625:2005
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SIST EN 14625:2005
EUROPEAN STANDARD
EN 14625
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2005
ICS 13.040.20
English version
Ambient air quality - Standard method for the measurement of
the concentration of ozone by ultraviolet photometry

Qualité de l'air ambiant - Méthode normalisée de mesurage Luftqualität - Messverfahren zur Bestimmung von Ozon in

de la concentration d'ozone par photométrie UV Luft mit dem UV-Verfahren
This European Standard was approved by CEN on 10 December 2004.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European

Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national

standards may be obtained on application to the Central Secretariat or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official

versions.

CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,

Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,

Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14625:2005: E

worldwide for CEN national Members.
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SIST EN 14625:2005
EN 14625:2005 (E)
Contents
Page

Foreword......................................................................................................................................................................4

1 Scope ..............................................................................................................................................................5

2 Normative references ....................................................................................................................................5

3 Terms and definitions ...................................................................................................................................5

4 Symbols and abbreviated terms ..................................................................................................................9

5 Principle........................................................................................................................................................12

5.1 General..........................................................................................................................................................12

5.2 Measuring principle.....................................................................................................................................12

5.3 Type approval test .......................................................................................................................................13

6 Sampling equipment ...................................................................................................................................13

6.1 General..........................................................................................................................................................13

6.2 Sampling location........................................................................................................................................13

6.3 Sampling inlet and sampling line...............................................................................................................14

6.4 Particulate filter............................................................................................................................................14

6.5 Control and regulation of sample flow rate ..............................................................................................15

6.6 Sampling pump for the manifold................................................................................................................15

7 Analyser equipment ....................................................................................................................................15

7.1 General..........................................................................................................................................................15

7.2 Interferences ................................................................................................................................................15

7.3 Ultraviolet absorption cell...........................................................................................................................15

7.4 Ultraviolet source lamp ...............................................................................................................................16

7.5 UV detector...................................................................................................................................................16

7.6 Ozone-specific scrubber.............................................................................................................................16

7.7 Switching valve............................................................................................................................................16

7.8 Temperature indicator.................................................................................................................................16

7.9 Pressure indicator .......................................................................................................................................16

7.10 Flow rate indicator.......................................................................................................................................17

7.11 Sampling pump for the analyser................................................................................................................17

7.12 Residence time in the sampling system and inside the analyser ..........................................................17

7.13 Internal ozone span source ........................................................................................................................17

8 Type approval of ultraviolet photometric ozone analysers.....................................................................17

8.1 General..........................................................................................................................................................17

8.2 Relevant performance characteristics and performance criteria ...........................................................17

8.3 Design changes ...........................................................................................................................................20

8.4 Procedures for determination of the performance characteristics during the laboratory test ...........20

8.5 Determination of the performance characteristics during the field test................................................30

8.6 Expanded uncertainty calculation for type approval...............................................................................34

9 Field operation and ongoing quality control ............................................................................................34

9.1 General..........................................................................................................................................................34

9.2 Suitability evaluation...................................................................................................................................34

9.3 Initial installation..........................................................................................................................................35

9.4 Ongoing quality control ..............................................................................................................................36

9.5 Calibration of the analyser..........................................................................................................................37

9.6 Checks ..........................................................................................................................................................38

9.7 Maintenance .................................................................................................................................................41

9.8 Data handling and data reports..................................................................................................................41

10 Expression of results ..................................................................................................................................42

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SIST EN 14625:2005
EN 14625:2005 (E)

11 Test reports and documentation................................................................................................................42

11.1 Type approval tests.....................................................................................................................................42

11.2 Field operation .............................................................................................................................................42

Annex A (normative) Correction for ambient nitric oxide ...................................................................................44

Annex B (normative) Calculation of lack of fit......................................................................................................45

Annex C (informative) Sampling equipment.........................................................................................................47

Annex D (informative) Sampling on micro scale..................................................................................................49

Annex E (informative) Ultra violet photometric analyser ....................................................................................50

Annex F (informative) Manifold testing equipment..............................................................................................51

Annex G (normative) Type approval......................................................................................................................52

Annex H (normative) Calculation of uncertainty in field operation at the hourly alert threshold value.........74

Bibliography..............................................................................................................................................................86

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SIST EN 14625:2005
EN 14625:2005 (E)
Foreword

This document (EN 14625:2005) has been prepared by Technical Committee CEN/TC 264 “Air quality”, the

secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an identical text or

by endorsement, at the latest by September 2005, and conflicting national standards shall be withdrawn at the

latest by September 2005.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following

countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,

Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

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SIST EN 14625:2005
EN 14625:2005 (E)
1 Scope

This document specifies a continuous measurement method for the determination of the concentration of ozone

present in ambient air based on the ultraviolet photometric measuring principle. This document describes the

performance characteristics, and sets the relevant minimum criteria required to select an appropriate ultraviolet

photometric ozone analyser by means of type approval tests. It also includes the evaluation of the suitability of an

anayser for use in a specific fixed site so as to meet the Directives data quality requirements and requirements

during sampling, calibration and quality assurance.

The method is applicable to the determination of the mass concentration of ozone present in ambient air in the

3 3

range from 0 µg/m to 500 µg/m . This concentration range represents the certification range for the type approval

test.
3 3
NOTE 1 0 µg/m to 500 µg/m of O corresponds to 0 nmol/mol to 250 nmol/mol of O .
3 3

The method covers the determination of ambient air concentrations of ozone in zones classified as rural areas,

urban and urban-background areas.

NOTE 2 Other ranges may be used for measurement systems applied at rural locations monitoring Ecosystems.

The results are expressed in µg/m (at 20 °C and 101,3 kPa).

When the standard is used for other purposes than the EU-directive, the range and uncertainty requirements need

not apply.
2 Normative 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.
ENV 13005, Guide to the expression of uncertainty in measurement

EN ISO 14956:2002, Air quality — Evaluation of the suitability of a measurement procedure by comparison with a

required measurement uncertainty (ISO 14956:2002)

ISO 13964:1998, Air quality — Determination of ozone in ambient air — Ultraviolet photometric method

3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
3.1
ambient air
outdoor air in the troposphere excluding workplace air
3.2
sample gas temperature
temperature at the sampling inlet outside the monitoring station
As stated in the relevant EU-legislation.
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SIST EN 14625:2005
EN 14625:2005 (E)
3.3
availability of the analyser

fraction of the total time period for which usually valid measuring data of the ambient air concentration is available

from an analyser
3.4
calibration

comparison of theanalyser response to a known gas concentration with a known uncertainty

3.5
certification range
concentration range for which the analyser is type approved
3.6
combined standard uncertainty

calculation result of combining the uncertainties determined from all performance characteristics specified in this

document according to the prescribed procedures given in this documentd
3.7
coverage factor

numerical factor used as a multiplier of the combined standard uncertainty in order to obtain an expanded

uncertainty
3.8
designated body

body which has been designated for a specific task (type approval tests and/or QA/QC activities in the field) by the

competent authority in the Member States

NOTE It is recommended that the designated body is accredited for the specific task according to EN ISO 17025.

3.9
expanded uncertainty

quantity defining an interval about the result of a measurement that may be expected to encompass a large fraction

of the distribution of values that could reasonably be attributed to the measurand

NOTE for the purpose of this document the expanded uncertainty is the combined standard uncertainty multiplied by a

coverage factor k = 2 resulting in an interval with a level of confidence of 95 %

3.10
fall time
difference between the response time (fall) and the lag time (fall)
3.11
independent measurement

individual measurement that is not influenced by a previous individual measurement by separating two individual

measurements by at least four response times
3.12
individual measurement

measurement averaged over a time period equal to the response time of the analyser

3.13
influence quantity

quantity that is not the measurand but that affects the result of the measurement (VIM 2.7), either an interferent

influence quantity (i.e. the concentration of a substance in the air under investigation that is not the measurand), or

an external influence quantity (i.e. a quantity that is not the measurand nor the concentration of a substance in the

air mass under investigation)
NOTE Examples are:

 presence of interfering gases in the flue gas matrix (interferent influence quantity);

 temperature of the surrounding air (external influence quantity);
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SIST EN 14625:2005
EN 14625:2005 (E)
 atmospheric pressure (external influence quantity);
 pressure of the gas sample (external influence quantity).
3.14
interference
response of the analyser to interferents
3.15
interferent

component of the air sample, excluding the measured constituent, that effects the output signal

3.16
initial ozone concentration

ozone concentration in the ambient air just before entrance into the sampling inlet

3.17
lag time

time interval from the instant at which a step change of sample concentration occurs at the inlet of the analyser to

the instant at which the output reading reaches a level corresponding to 10 % of the stable output reading

3.18
lag time (fall)
lag time for a negative step change
3.19
lag time (rise)
lag time for a positive step change
3.20
limit value

level fixed on the basis of scientific knowledge, with the aim of avoiding, preventing or reducing harmful effects on

human health and/or the environment as a whole, to be attained within a given period and not to be exceeded once

attained
3.21
lack of fit

maximum deviation of the average of a series of measurements at the same concentration from the linear

regression line
3.22
long-term drift

difference between zero or span readings over a determined period of time (e.g. period of unattended operation)

3.23
monitoring station

enclosure located in the field in which an ozone analyser has been installed in such a way that its performance and

operation comply with the prescribed requirements
3.24
parallel measurement

measurements from different analysers, sampling from one and the same sampling manifold, starting at the same

time and ending at the same time
3.25
performance characteristic
one of the parameters assigned to equipment in order to define its performance
3.26
performance criterion

limiting quantitative numerical value assigned to a performance characteristic, to which conformance is tested

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SIST EN 14625:2005
EN 14625:2005 (E)
3.27
period of unattended operation

time period over which the drift is within the performance criterion for long-term drift

3.28
repeatability (of results of measurement)

closeness of the agreement between the results of successive individual measurements of the same measurand carried out

under the same conditions of measurement [1]

NOTE These conditions are called laboratory repeatability conditions and include:

-the same measurement procedure;
-the same observer,
-the same analyser, used under the same conditions;
-at the same location;
-repetition over a short period of time.
3.29
reproducibility under field conditions

closeness of the agreement between the results of simultaneous measurements with two analysers in ambient air

carried out under the same conditions of measurement
NOTE 1 These conditions are called field reproducibility conditions and include:
the same measurement procedure;
two identical analysers, used under the same conditions;
at the same monitoring station;
the period of unattended operation.

NOTE 2 In this document the reproducibility under field conditions is expressed as a value with a level of confidence of 95 %

3.30
residence time inside the analyser

time period for the sampled air to be transported from the inlet of the analyser to the outlet of the absorption cell

3.31
residence time in the sampling system

time period for the sampled air to be transported from the sampling inlet (of the sampling system) to the inlet of the

analyser
3.32
response time

time interval from the instant at which a step change of sample concentration occurs at the inlet of the analyser to

the instant at which the output reading reaches a level corresponding to 90 % of the stable in output reading

3.33
response time (fall)
response time at a negative step change
NOTE Response time (fall) is the sum of the lag time (fall) and the fall time.
3.34
response time (rise)
response time at a positive step change
NOTE Response time (rise) is the sum of the lag time (rise) and the rise time.
3.35
rise time
difference between the response time (rise) and the lag time (rise)
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SIST EN 14625:2005
EN 14625:2005 (E)
3.36
sampled air
ambient air that has been sampled through the sampling inlet and sampling system
3.37
sampling inlet

entrance to the sampling system where ambient air is collected from the atmosphere

3.38
short-term drift

difference between zero or span readings at the beginning and end of a 12 h period

3.39
standard uncertainty
uncertainty of the result of a measurement expressed as a standard deviation
[ENV 13005]
3.40
surrounding temperature

temperature of the air directly surrounding the analyser (temperature inside the monitoring station or laboratory)

3.41
type approval

decision taken by a designated body that the pattern of an analyser conforms to the requirements as laid down in

this document
3.42
type approval test

examination of two or more analysers of the same pattern which are submitted by a manufacturer to a designated

body; including the tests necessary for approval of the pattern
3.43
uncertainty(of measurement)

parameter associated with the result of a measurement that characterises the dispersion of the values that could

be attributed to the measureand
4 Symbols and abbreviated terms

For the purposes of this document, the following symbols and abbreviated terms apply.

A availability of the analyser
Av average concentration of the measurand during the field test

b sensitivity coefficient of the analyser to sample gas pressure change expressed as a percentage of the

measured value, obtained during the laboratory type approval test
b sensitivity coefficient of the analyser to sample gas temperature change
b sensitivity coefficient of the analyser to surrounding air temperature change
b sensitivity coefficient of the analyser to electrical voltage change
C O concentration of the applied gas
C average concentration of the measurements at sampling gas pressure P
P1 1
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SIST EN 14625:2005
EN 14625:2005 (E)
C average concentration of the measurements at sampling gas pressure P
P2 2

C average concentration of the measurements at span level at the beginning of the drift period

s,1

C average concentration of the measurements at span level at the end of the drift period

s,2
c test gas concentration
C average concentration of the measurements at sample gas temperature T
T1 1
C average concentration of the measurements at sample gas temperature T
T2 2
C average concentration reading of the measurements at voltage V
V1 1
C average concentration reading of the measurements at voltage V
V2 2

C average concentration of the measurements at zero at the beginning of the drift period

z,1

C average concentration of the measurements at zero at the end of the drift period

z,2

average of at least four independent measurements during the constant concentration period (t )

const

average of at least four independent measurements during the variable concentration period (t )

var
average difference of parallel measurements
d the ith difference in a parallel measurement
f,i
D long-term drift at span concentration c
l,s t
D long-term drift at zero
l,z
D short-term drift at span level
s,s
D short-term drift at zero
s,z
D difference sample/calibration port
E sample system collection efficiency
F response factor in concentration units per voltage output of the analyser
P sampling gas pressure P
1 1
P sampling gas pressure P
2 2
R mean analyser response to the test gas directly sampled by the analyser
r reproducibility under field conditions
r absolute reproducibility in the field
f,abs
R mean analyser response to the test gas via the sample manifold
s repeatability standard deviation at zero
r,z
s repeatability standard deviation at concentration c
r,ct t
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SIST EN 14625:2005
EN 14625:2005 (E)
s reproducibility standard deviation under field conditions
r,f
s repeatability standard deviation
T surrounding air temperature
T sample gas temperature T
1 1
T sample gas temperature T
2 2
t relative difference between response time (rise) and response time fall
t response time (fall)
t surrounding air temperature at the laboratory

t two-sided Students t-factor at a confidence level of 0,05, with n-1 degrees of freedom

n-1, 0,05
t response time (rise)

t time period of the field test minus the time for calibration, conditioning and maintenance

t total time period with validated measuring data
t whole number of t and t pairs
V O3 zero
V minimum voltage V (V) specified by the manufacturer
1 min
V maximum voltage V (V) specified by the manufacturer
2 max
average of measurements
x first average of the measurements at T just after calibration
1 l
x second average of the measurements at T just before calibration
2 l
x average of the measurements at zero
x average of the measurements at concentration c
ct t
X averaging effect
x average of the measurements using the calibration port
X influence quantity of H O with concentration 19 mmol/mol
H2O,z,ct 2
x the ith measurement
influence quantity of the interferent at concentration c
X t
int,ct
X influence quantity of the interferent at zero
int,z
X lack of fit (largest residual from the linear regression function)
x average of the measurements using the sample port

X difference between the readings of the recent zero check and the most recent calibration

x average of the measurements at T or T
T min max
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SIST EN 14625:2005
EN 14625:2005 (E)
X influence quantity of benzene with concentration 1 µmol/mol
benx,z,ct
X difference between the readings of two consecutive zero checks
(x ) the ith measurement result of analyser 1
1,f i

(x ) the ith measurement result of analyser 2 at the same time as the measurement of analyser 1

2,f i
Z reading of the first zero check
Z reading of the second zero check
∆P measured pressure drop induced by the manifold pump

∆R change in the analyser’s response due to the influence of the pressure drop induced by the manifold

pump, expressed as a percentage
5 Principle
5.1 General

This document describes the method for measurement of the concentration of ozone in ambient air by means of

ultraviolet photometry. The requirements, the specific components, the ultraviolet photometric analyser and its

sampling system are described. For the analyser a number of performance characteristics with associated

minimum performance criteria are given. The actual values of these performance characteristics for a specific type

of analyser have to be determined in a so-called type approval test for which procedures have been described. The

type approval test comprises a laboratory and a field test. The selection of a suitable analyser for a specific

measuring task in the field is based on the calculation of the combined expanded uncertainty of the measuring

method. In this combined expanded uncertainty calculation the actual values of the various performance

characteristics of a type approved analyser and the site-specific conditions at the monitoring station are taken into

account. The expanded uncertainty of the method shall meet the requirements of the (EU) legislation. For ongoing

measurements in the field, requirements and recommendations for quality assurance and quality control are given

(see 9.4).
5.2 Measuring principle

Sampled air is drawn continuously through an optical absorption cell where it is irradiated by monochromatic

radiation, c
...

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