Bsi bs en 14902 2005 (2009)

30157365 pdf BRITISH STANDARD BS EN 14902 2005 Incorporating corrigendum no 1 Ambient air quality — Standard method for the measurement of Pb, Cd, As and Ni in the PM10 fraction of suspended particula[.]

corrigendum no 1

Ambient air quality —

Standard method for

This British Standard was

published under the authority

of the Standards Policy and

Strategy Committee

on 27 September 2005

© BSI 2007

National foreword

This British Standard was published by BSI It is the UK implementation of

EN 14902:2005, incorporating corrigendum October 2006

The UK participation in its preparation was entrusted by Technical Committee EH/2, Air quality, to Subcommittee EH/2/3, Ambient atmospheres

A list of organizations represented on this subcommittee can be obtained on request to its secretary

This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application

Compliance with a British Standard cannot confer immunity from legal obligations.

Amendments issued since publication

17049

Corrigendum No 1 30 April 2007 Equation 5 replaced

NORME EUROPÉENNE

ICS 13.040.20 Incorporating corrigendum October 2006

English versionAmbient air quality - Standard method for the measurement of

Pb, Cd, As and Ni in the PM10 fraction of suspended particulate

matter

Qualité de l'air ambiant - Méthode normalisée pour la

mesure de Pb, Cd, As et Ni dans la fraction MP10 de la

matière particulaire en suspension

Außenluftbeschaffenheit - Standardisiertes Verfahren zur Bestimmung von Pb/Cd/As/Ni als Bestandteil der PM10

Fraktion des Schwebstaubes

This European Standard was approved by CEN on 27 June 2005.

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

C O M IT É E U R O P É E N D E N O R M A LIS A T IO N EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: rue de Stassart, 36 B-1050 Brussels

Page

Foreword .3

1 Scope 4

2 Normative references 5

3 Terms, definitions and abbreviations 5

4 Principle 8

5 Requirements 9

6 Reagents and gases 10

7 Apparatus 11

8 Sampling 12

9 Analysis 14

10 Quality control 22

11 Calculation of results 23

12 Estimation of the measurement uncertainty of the method 26

13 Performance characteristics determined in field tests 27

14 Reporting of results 32

Annex A (informative) Examples of closed vessel microwave digestion procedures 33

Annex B (informative) Typical laboratory filter blank values as determined in the field validation tests 35

Annex C (informative) Analytical interferences 36

Annex D (informative) Approach to uncertainty estimation used in the field validation tests 40

Annex E (normative) List of minimum QA / QC procedures 46

Annex F (informative) Procedure for the determination of the uncertainty of the method for an individual laboratory 48

Annex ZA (informative) Relationship with EU Directives 53

Bibliography .54

This European Standard (EN 14902:2005) 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 February 2006, and conflicting national standards shall be withdrawn at the latest

1 Scope

This European Standard specifies a method for the determination of particulate lead (Pb), cadmium (Cd), arsenic(As) and nickel (Ni) in ambient air that can be used in the framework of the European Council Directive on AmbientAir Quality Assessment and Management [1] and the 1st [2] and 4th [3] Daughter Directives Performancerequirements with which the method has to comply are specified in this European Standard The performance characteristics of the method were determined in comparative field validation tests carried out at four Europeanlocations (see[4])

This European Standard specifies a method for sampling of Pb, Cd, As and Ni as part of the PM10 aerosol,microwave digestion of the samples and analysis by graphite furnace atomic absorption spectrometry or byinductively coupled plasma (quadrupole) mass spectrometry

This European Standard is applicable for the measurement of Pb, Cd, As and Ni as part of the PM10 aerosolfraction in the concentration ranges listed in Table 1

Table 1 — Working ranges of the method in ng/m³

2 Normative references

The following referenced documents are indispensable for the application of this European Standard For dated references, only the edition cited applies For undated references, the latest edition of the referenced document(including any amendments) applies

EN 12341:1998, Air quality – Determination of the PM10 fraction of suspended particulate matter – Reference

method and field test procedure to demonstrate reference equivalence of measurement methods.

ENV 13005:1999, Guide to the expression of uncertainty in measurement 1

3 Terms, definitions and abbreviations

3.1 Terms and definitions

For the purpose of this European Standard, the following terms and definitions apply

solution prepared from a laboratory filter blank or a field filter blank by the process of sample dissolution

NOTE A laboratory filter blank solution or a field filter blank solution might need to be subjected to further operations, e.g dilution and/or addition of an internal standard(s), if such operations are applied to the sample solutions in order to produce test solutions that are ready for analysis

3.1.3

calibration blank solution

calibration solution prepared without addition of stock standard solution or working standard solution, for which theconcentration of the analyte(s) of interest is considered to be zero

certified reference material

reference material, in which one or more of property values are certified by a technically valid procedure,accompanied by or traceable to a certificate or other documentation that is issued by a certifying body [5]

3.1.6

field filter blank

filter that is taken through the same procedure as a sample, except that no air is drawn through it It is transported

to the sampling site, mounted in the sampling unit, dismounted, returned to the laboratory and worked up in the same way as a sample

3.1.7

internal standard solution

solution added to sample, blank and calibration solutions to correct for instrumental fluctuations during analysis, containing (a) suitable element(s) at (a) suitable concentration(s)

3.1.8

instrumental detection limit

lowest amount of an analyte that is detectable using an instrument, as determined by repeated measurements of areagent blank

3.1.9

laboratory filter blank

unused filter that does not leave the laboratory and is taken through the same analytical procedure as a sample This filter is taken from the same batch as used for sampling

3.1.10

limit value

level fixed on the basis of scientific knowledge, with the aim of avoiding, preventing or reducing harmful effects onhuman health and/or the environment as a whole, to be attained within a given period and not to be exceeded onceattained

3.1.13

method detection limit

lowest amount of an analyte that is detectable using the method, as determined by analysis of laboratory filterblanks

quality control solution

solution that is analysed together with the sample solutions to provide information on the repeatability of theanalytical method, results for which are plotted on a quality control chart to verify that a method is performingsatisfactorily

reagent blank solution

solution that contains all the reagents used during the analysis of the sample, but without the sample and filtermatrix

3.1.20

repeatability (of results of measurements)

closeness of the agreement between the results of successive measurements of the same measurand carried outunder the same conditions of measurement [6]

3.1.21

reproducibility (of results of measurements)

closeness of the agreement between the results of measurements of the same measurand carried out under changed conditions of measurement [6]

3.1.22

sample solution

solution prepared from a sample by the process of sample dissolution

NOTE A sample solution might need to be subjected to further operations, e.g dilution and/or addition of an internal standard(s), in order to produce a test solution that is ready for analysis.

stock standard solution

solution used for preparation of calibration solutions, containing one or more of the analyte(s) of interest at (a) concentration(s) traceable to national or International Standards

3.1.27

sub-sample (of a filter)

part of a large filter, cut out for analytical reasons, that is representative of the whole

3.1.28

suspended particulate matter

notion of all particles surrounded by air in a given, undisturbed volume of air

test solution

blank solution or sample solution that has been subjected to all operations required to bring it into a state in which it

is ready for analysis, e.g dilution and/or addition of an Internal Standard(s)

NOTE If subject to no further operations before analysis, then the blank test solution is identical to the blank solution The same is true for the sample test solution and sample solutions.

3.1.31

uncertainty (of a measurement)

parameter associated with the result of a measurement that characterises the dispersion of the values that could reasonably be attributed to the measurand

[ENV 13005:1999]

3.1.32

working standard solution

solution prepared by dilution of the stock standard solution(s), that contains the analyte(s) of interest at (a)

concentration(s) better suited to preparation of calibration solutions

3.2 Abbreviations

AAS atomic absorption spectrometry;

amu atomic mass unit;

CRM certified reference material;

GFAAS graphite furnace atomic absorption spectrometry;

HDPE high density polyethylene;

HVS high volume sampler, as described in EN 12341:1998, Annex B.2;

ICP-MS inductively coupled plasma – mass spectrometry;

LDPE low density polyethylene;

LVS low volume sampler, as described in EN 12341:1998, Annex B.1;

PFA perfluoroalkoxy polymer;

NOTE In order to meet the requirements of this European Standard, particularly with respect to detection limits, it might be necessary to increase the sampling time for samplers that have low flow rates.

5.3 Analytical requirements

5.3.1 Method detection limit

The method detection limits, based on laboratory filter blanks, shall be less than or equal to 10 % of the limit value for Pb and less than or equal to 10 % of the target values for Cd, As and Ni, as specified in the 1st and 4th DaughterDirectives [2], [3] The method for calculating method detection limits is described in 11.5

NOTE If it is necessary to perform measurements at lower concentrations within the working ranges of the method given in Table 1, lower method detection limits will be necessary (see Table 7).

5.3.3 Homogeneity requirement for sub-samples

The relative standard deviation of the lead content of sub-samples, when determined in accordance with the procedure described in 9.6, shall not exceed 5 %

6 Reagents and gases

6.1 Water, ultrapure, distilled or deionised.

NOTE It is recommended that the water used be obtained from a water purification system that delivers ultrapure water having a resistivity of 0,18 MΩ ·m or greater at 25 °C

6.2 Nitric acid (HNO 3 ), concentrated, ρ about 1,42 g/ml, mass fraction about 70 %, high purity grade

[concentration stated by the manufacturer or supplier < 0,005 mg/l for As, Cd, Ni and Pb (typical concentrations aregenerally 10 times lower)], sub-boiled before use if necessary

WARNING Concentrated nitric acid is corrosive and oxidising, and nitric acid fumes are irritants Avoid exposure by contact with the skin or eyes, or by inhalation of fumes Use suitable personal protective equipment (including suitable gloves, face shield or safety spectacles, etc) when working with the concentrated or dilute nitric acid

6.3 Nitric acid for cleaning purposes, add approximately 800 ml of ultrapure water (6.1) to a 1 litre one-mark

volumetric flask Carefully add 100 ml of concentrated nitric acid (6.2) to the flask and swirl to mix Allow to cool,dilute to 1 l with water and mix thoroughly

6.4 Hydrogen peroxide (H 2 O 2 ), mass fraction about 30 %, high purity grade [concentration stated by the

manufacturer or supplier < 0,005 mg/l for As, Cd, Ni and Pb (typical concentrations are generally 10 times lower)]

WARNING Hydrogen peroxide is corrosive and oxidising Avoid exposure by contact with the skin or eyes Use suitable personal protective equipment (including suitable gloves, face shield or safety spectacles, etc) when working with hydrogen peroxide.

6.5 Stock standard solutions, single element or multi-element Use commercial standard solutions with certified

concentrations traceable to national or International Standards Observe the manufacturer's expiration date orrecommended shelf life

6.6 Working standard solution, prepare a working standard solution containing the analyte(s) of interest at a

concentration(s) that is better suited to preparation of the calibration solutions, if desired, by appropriate dilution ofthe stock standard solutions (see 6.5)

6.7 Matrix modifier, e.g NH4H2PO4, Mg(NO3)2 or Pd(NO3)2, or a combination of these, if required, for GFAAS analysis

6.8 Argon, liquid or cylinder of a purity suitable for use in GFAAS or ICP-MS analysis.

6.9 Certified Reference Material (CRM), with a sample matrix that is as representative as possible of ambient air

PM10 particulate matter2)

2) “NIST 1648 “Urban Particulate Matter” from National Institute of Standards & Technology, USA, is an example of a suitable

product available commercially This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of this product NIST 1648 was used as reference material during the validation of the method and is named in the text as CRM 1.”

7 Apparatus

7.1 Sampling equipment

7.1.1 PM10 samplers, equivalent to EN 12341 HVS or LVS may be used and the samplers may be single-filter

devices or sequential samplers

NOTE To minimise contamination of the sample, all components of the filter holder in contact with the filter should be made

of a suitable material with as low a metal content as possible, such as PTFE, glass, quartz etc.

7.1.2 Greasing agent, if required, suitable for greasing the sampler impaction plate.

7.1.3 Filters, of a diameter suitable for use with the samplers (7.1.1), with a separation efficiency of at least

99,5 % at an aerodynamic diameter of 0,3 µm Each new batch of filters shall be tested to confirm that the filterblank variability is sufficiently low so that the method detection requirements of 5.3.1 are met

NOTE 1 It is recommended that filters used should be sourced from a manufacturer who has determined the separation efficiency of the filter material according to standard methods such as [8] or [9]

NOTE 2 The metal content of the filter should be as low as possible because it is usually the case that higher filter blank values lead to higher variability of the blank values.

NOTE 3 Quartz fibre filters, cellulose nitrate and cellulose acetate membrane filters have been found suitable in the field validation tests (see Annex B) Further information can be found in [10].

NOTE 4 In choosing a filter, the user should consider the initial pressure drop across the filter and the increase in this that occurs due to the collection of the dust and ensure that there is no possibility of an excessive pressure drop developing during sampling This depends on the type of filter (i.e membranes), unusual high concentrations of PM10, the use of longer sampling time than 24 h and the capability of the sampling device to handle the resulting pressure drop Quartz fibre filters are proven to

be efficient in most cases although they have weak mechanical properties.

7.1.4 Flowmeter, with a measurement uncertainty that is sufficient to enable the volumetric flow rate of the

samplers (7.1.1) to be measured to within ± 5 % The calibration of the flowmeter shall be traceable to(inter)national standards

NOTE It is recommended that the flowmeter used should be capable of measuring the volumetric flow rate to within ± 2 %

or better.

7.2 Laboratory apparatus

Ordinary laboratory apparatus, and 7.2.1- 7.2.7

7.2.1 Microwave digestion system, designed for closed vessel sample digestion in the laboratory, with power

output regulation, fitted with a temperature control system capable of sensing the temperature and automaticallyadjusting the microwave power output The microwave cavity shall be corrosion resistant and well ventilated, withall electronics protected against corrosion to ensure safe operation

NOTE A leakage detection or pressure control system is very useful, since it provides a safeguard against the possibility of sample loss due to excessive pressure build-up and partial venting of the sample vessels.

WARNING Ensure that the manufacturer’s safety recommendations are followed.

7.2.2 Sample vessels, designed for high pressure microwave digestion, having a system for controlled

pressure relief, capable of withstanding an operating temperature of 220 °C and a pressure of at least 50 bar, and having an internal volume of at least 50 ml, e.g vessels having an inner liner and cover made of a microwave transparent and chemically resistant material (usually a fluorocarbon polymer such as TFM or PFA)

7.2.3 One-mark volumetric flasks, made of borosilicate glass, quartz, polyethylene or fluorocarbon polymer

NOTE Solutions with ultra-trace level analytes are commonly stored in thoroughly cleaned vessels made of polyethylene (LDPE, HDPE) or fluorocarbon polymer (e.g PFA, PTFE).

7.2.4 Punching tool, if required, suitable for taking sub-samples of large filters without contamination

7.2.5 Transport containers, suitable for transport of filters from the sampling site back to the laboratory, made

of inert low metal background materials such as HDPE, PP, polycarbonate, PTFE, glass or quartz

Either

7.2.6 Graphite furnace atomic absorption spectrometer, equipped with hollow cathode lamps or

electrodeless discharge lamps for the elements of interest, capable of carrying out simultaneous background correction at the measurement wavelengths using a continuum source such as a deuterium lamp to correct for non-specific attenuation (see 5.1.5 of [11]) or using a Zeeman background correction system

Or

7.2.7 Inductively coupled plasma - mass spectrometer, quadrupole instrument capable of scanning the

mass range from 5 amu to 250 amu with a minimum resolution capability of 1 amu peak width at 5 % peak height, equipped with a data system that allows correction of isobaric interferences and the application of the internal standard technique

NOTE The use of alternative ICP-MS instrumental configurations, e.g high resolution mass spectrometers, quadrupole mass spectrometers equipped with reaction or collision cells; cold plasma systems etc., can reduce spectral interferences.

8 Sampling

8.1 Preparation of the sampling equipment

8.1.1 Consult the manufacturer’s instruction manual to determine the minimum voltage and power requirements

of the sampler (7.1.1) and ensure that an adequate power supply is available at the sampling site

8.1.2 Clean the sampler inlet, suction pipe, filter change mechanism, filter cassettes and all other parts of the

sampler that can come in contact with the filter before use according to the manufacturer’s specifications Similarly,inspect greased parts like impaction plates before use, clean them if necessary and grease them again

8.3.1 Reject filters that could have been contaminated, e.g during packing and/or transport.

8.3.2 Inspect each filter before use for pin holes and other imperfections, such as chaffing, loose material,

discoloration and non-uniformity For example, use a magnifying lens with a light or check in front of an area light Reject any filter if its integrity is suspect

8.3.3 Assign each filter a unique identifier and place it in a labelled, sealed container (7.2.5) for storage and

transportation to the field If the filter has to be marked for identification purposes, do not mark it in an area of the filter that will be analysed

8.3.4 Establish a filter log (i.e a chain of custody book/record) in which to document the use of each filter.Record the lot number of the filters used in the filter log If the sampler to be used is a sequential sampler that operates continuously for a programmed period, load the required number of filters into a labelled filter cartridge and seal it ready for transportation to the field Record details of which filter was loaded into which position in thecartridge

8.3.5 Take laboratory filter blanks (see 3.1.9) periodically during preparation of a batch of filters, so that the

number of laboratory filter blanks is at least 5 % of the number of filters that will be used for sampling in the field

8.4 Sample collection

8.4.1 Set up the sampler (7.1.1) in the field according to the manufacturer’s instructions, ensuring that the siting

requirements in 5.1 are met

8.4.2 Carry out a leak test and check the flow rate of the sampler using the calibrated flowmeter (7.1.4) before

use and at least every three months, following the manufacturer’s instructions If the flow rate deviates by more than 5 % from its nominal value, calibrate the sampler by adjusting the flow rate as necessary

NOTE It is recommended that a leak test and a flow rate calibration are carried out in the laboratory in order to identify problems with the sampler at an early stage.

8.4.3 Take field filter blanks (see 3.1.6) periodically at each site (at least once for every 20 filters used for

sampling)

8.4.4 Load either an unexposed filter (for single filter devices) or a cartridge of unexposed filters (for sequential

samplers) into the sampler at the start of the sampling period Program the sampler following the manufacturer'sinstructions, start the timer and record details of the start time, flow rate and filter code(s) in the filter log

8.4.5 Collect the filter from the sampler at the end of the sampling period, replace it in its uniquely marked

transport container and seal it for transportation to the laboratory (for single filter devices) For sequential samplers, collect the cartridge of used filters and prepare it for transportation to the laboratory

NOTE If filters are folded for storage (for easier transportation), then it will be necessary to analyse the whole filter as folding can affect the distribution of particles on the filter surface.

8.4.6 Record full details of each sample in the filter log, including the stop time, the flow rate, the air sample

volume, in m³; any mechanical or electrical failures, the meteorological conditions during the sampling period and any other data that could be important for later evaluation of the sampling

8.4.7 Clean and grease the inlet impaction plate, if applicable, at least once every 15 d of sampling Perform

intensive cleaning of the PM10 sampling head according to the manufacturer’s instructions at least once every sixmonths

9 Analysis

9.1 Cleaning of laboratory apparatus

9.1.1 Cleaning of microwave digestion vessels

Clean microwave digestion vessels before use by taking them through the same procedure used for sampledigestion (see 9.2), but adding just nitric acid (6.3) and hydrogen peroxide (6.4) to the vessels Afterwards rinse the vessels three times with ultrapure water (6.1) Shorter cleaning times or alternative cleaning procedures may be used if it can be demonstrated that they are effective and that the method detection limit requirements (5.3.1) are fulfilled

If there are tide mark residues from the previous digestion, try to remove them by following the manufacturer’scleaning instructions or for example by using an ultrasonic bath

NOTE It is advisable to retain a set of digestion vessels dedicated for the analysis of samples specified in this European Standard.

9.1.2 Cleaning of labware

Clean all labware (volumetric flasks, autosampler tubes, etc) thoroughly before use according to the followingprocedure:

• soak labware in nitric acid (6.3), at least overnight; and preferably for several days;

• rinse three times with nitric acid (6.3);

• rinse three times with ultrapure water (6.1);

• dry (at below 50 °C) and store in a dust protected area

Alternative cleaning procedures may be used if it can be demonstrated that they are effective and the method detection limit requirements (5.3.1) are fulfilled

NOTE It is advisable to retain a set of labware dedicated for the analysis of samples specified in this European Standard.

9.2 Sample digestion

9.2.1 If the whole filter is to be analysed, transfer it into a labelled microwave sample vessel If it is necessary toensure complete submersion of filter in the digestion acid, first fold the filter or cut it into small pieces using ceramicscissors (made of aluminium oxide) or an alternative cutting implement that will not contaminate the sample Alternatively if only part of the filter is analysed, take a sub-sample from the filter using the punching tool (7.2.4) or

by cutting a strip from the filter

NOTE The cutting off from a filter is described in 6.2.1 of [10].

Take care not to contaminate the sub-sample with wear from the punching tools or support plate under the punch.Transfer the sub-sample into the digestion vessel

NOTE It might be necessary to analyse a sub-sample of the filter because of the limited amount of material that can be digested in the microwave digestion vessels used

9.2.2 Carefully add suitable volumes of nitric acid (6.2) and hydrogen peroxide (6.4) to each vessel (e.g 8 mlnitric acid and 2 ml hydrogen peroxide for a 50 ml vessel size and a 50 mm diameter filter) and cover with the lid.Place the sample vessels, evenly distributed, on the turntable of the microwave digestion apparatus, sealing them according to the manufacturers' instructions Alternative digestion mixtures which have been demonstrated to meetthe recovery rate requirements in 5.3.2 may also be used

NOTE 1 Incomplete submersion of filters in the digestion acid causes a particular problem when filters are not fully dissolved

in the digestion procedure In such circumstances it might be necessary to increase the digestion volume and the duration of the microwave digestion programme, respecting the manufacturer’s recommendations regarding the maximum volume of acids NOTE 2 Sample digestion using hydrofluoric acid and nitric acid, as an alternative to nitric acid and hydrogen peroxide, has also been evaluated in laboratory tests [7] and found to be applicable.

9.2.3 Program the apparatus to reach approximately 180 °C within 20 min, to increase slowly the temperature

up to approximately 220 °C and then to hold the temperature for about 20 min The ramp and hold times aredependent on the used apparatus and vessels and may be adjusted, for examples see Annex A Alternative procedures or heating techniques which have been demonstrated to meet the recovery rate requirements in 5.3.2 may also be used

9.2.4 After the digestion procedure allow the vessels to return to room temperature Carefully open the cooled vessels in a fume cupboard and transfer the sample solutions into labelled volumetric flasks (7.2.3) of suitable capacity (e.g 50 ml) containing ultrapure water (6.1) Wash down the lid and the sides of each digestion vessel, and the filter if it remains undigested, three times with ultrapure water and transfer the washings into the volumetricflask Dilute to the mark and shake well Filter or centrifuge the solution to separate undissolved filter material orsample, if necessary

WARNING Pressurised vessels can be dangerous Handle the vessels following the manufacturer’s instructions.

9.2.5 For digestion of the laboratory filter blanks (see 8.3.5) and the field filter blanks (see 8.4.3), follow the procedure described in 9.2.1 to 9.2.4 Also prepare reagent blanks solutions by taking vessels without filtersthrough the procedure described in 9.2.2 to 9.2.4

NOTE It is recommended to test the blank values of the reagents before use.

9.3 Selection of analytical technique

Follow either the procedure described in 9.4 GFAAS analysis or in 9.5 ICP-MS analysis

NOTE 1 For general guidelines on GFAAS see [12]

NOTE 2 Information on the methods used by laboratories participating in the field validation tests is given in the field validation test report [7]

NOTE 3 The use of very concentrated acid solutions can damage the device and lead to problems of contamination mainly for the measurement of Ni.

NOTE 4 Alternatively hydride generation atomic absorption spectrometry can be used for Arsenic analysis if it has been demonstrated to meet the requirements in 5.3.1 and 5.3.2.

Test the developed method by digesting and analysing certified reference material Calculate the analytical recovery using the procedure described in 10.3 and verify that it meets the requirements specified in 5.3.2 It is alsovery important to take account of any interferences (see C.1)

9.4.1.2 Analytical wavelengths

Suitable wavelengths for determination of Pb, Cd, As and Ni are given in the following table:

Table 3 — Suitable wavelengths for determination of Pb, Cd, As and Ni

9.4.1.5 Matrix-matching of calibration solutions

Decide to what extent it is necessary to match the matrix of the calibration solutions with that of the samplesolutions If the sample solutions contain residue from the filter matrix it could be necessary to prepare thecalibration solutions by spiking laboratory filter blank solutions If it is decided to match only the acid content of the calibration and sample solutions ensure that no filter matrix effects exist Alternatively, use the method of standardadditions

NOTE In the laboratory tests [7] it has been shown that no significant filter matrix effect normally exists

9.4.1.6 Calibration range

Select a range of concentrations over which to prepare the calibration solutions Take into consideration the maximum air concentration of each analyte that might need to be measured, the air sample volume and the sample solution volume Table 4 gives an indication of typical calibration ranges

Table 4 — Typical calibration ranges

Typical range µg/l

9.4.2 Preparation of calibration solutions

Prepare a calibration blank solution and at least three calibration solutions from the stock standard solutions (6.5)

or the working standard solution(s) (see 6.6), covering the range of concentrations selected in 9.4.1.6, matrixmatching if appropriate (see 9.4.1.5) Use freshly prepared calibration solutions unless it has been demonstrated that calibration solutions are stable for a prolonged period

9.4.3 Preparation for analysis

9.4.3.1 Visual inspection

Perform a visual check to ensure that the instrument and ancillaries are in good order before commencing work.Follow the instrument manufacturer's recommendations

9.4.3.2 Setting up the instrument

Set up instrumentation (spectrometer, lamps, cooling water supply, gas supply) according to the manufacturer´sinstructions Condition the graphite tube before use, if necessary Wait until the lamp energy is stable beforestarting the first measurement

9.4.3.3 Performance checks and fault diagnostics

Carry out suitable performance checks on a routine basis Record the results of the tests, preferably using control charts Use more rigorous fault diagnostics if it is suspected that the instrument is not functioning properly Followthe instrument manufacturer's recommendations

9.4.4 Analysis

9.4.4.1 Calibration

Measure the calibration solutions in order of increasing concentration and use the instrument's computer togenerate calibration functions for the metals of interest Repeat the calibration if the determination coefficient forany of the metals of interest, R2, is less than 0,995

9.4.4.2 Measurement of sample solutions

Make at least three replicate measurements of the reagent blank solutions, laboratory filter blank solutions, fieldfilter blank solutions and sample solutions and determine the concentrations of the metals of interest using the appropriate calibration function If the measured concentration of a sample solution is above three times the method detection limit the relative standard deviation of the three replicate measurements shall be less than 10 %

If this is not the case repeat the analysis and if the problem still exists check the instrumental set-up

If the concentration of any of the metals of interest in a sample solution is found to be above the upper limit of thecalibration range, dilute the solution by a suitable factor and repeat the analysis Record the dilution factor

NOTE Long term stability for refractory elements such as nickel can be adversely affected by tube behaviour, i.e by nickel uptake Therefore it is advantageous to recalibrate periodically, e.g every 10 samples.

9.4.5 Quality control measurement

Follow the quality control procedures prescribed in Clause 10

NOTE 1 For general guidelines on ICP-MS see [13].

NOTE 2 Information on the methods used by laboratories participating in the field validation tests is given in the field validation test report [7].

Test the developed method by digesting and analysing a certified reference material (6.9) Calculate the analytical recovery using the procedure described in 10.3 and verify that it meets the requirements specified in 5.3.2 It is alsovery important to take account of any interferences (see C.2)

9.5.1.2 Sample introduction system

Decide which type of sample introduction system to use Take into consideration the nature of the sample solutionmatrix and the required sensitivity In most instances the standard sample introduction system supplied by the instrument manufacturer will be adequate

NOTE If the sample solutions contain hydrofluoric acid it is necessary to use a corrosion-resistant sample introduction system.

9.5.1.3 Analytical conditions

9.5.1.3.1 Analytical masses

Decide at which masses to make ICP-MS measurements One or more masses may be used for each analyte If measurements are to be made at more than one mass, produce and follow a written protocol for reporting results.Table 5 shows relevant analytic masses and possible internal standards

NOTE If two analyte masses are used, a suitable protocol might simply be to report the mean result.

Table 5 — Principal analyte masses Analyte Abundance

a

% natural abundance

Principal analyte masses

amu

Preferred analyte mass

amu

Possible internal standards

Possible isobaric and polyatomic interferences

a Taken from Weast, R C and Astle, M J (Editors), CRC Handbook of Chemistry and Physics, 60th edition,

CRC Press Inc., Boca Raton, USA, 1980.

9.5.1.3.2 Internal standards

Decide which internal standards to use to correct for sensitivity changes caused by transport effects, changes in plasma conditions, changes in mass response etc Carefully select the internal standard and ensure that they aresuitable for the intended purpose, which may vary according to the performance characteristics of the ICP-MS instrument used Refer to Table 6 for information about possible and preferred internal standards and take intoconsideration the guidance given in the following notes

Ensure that the internal standards are compatible with the sample solution matrix and verify that the sample solutions do not contain a significant concentration of the internal standard elements

NOTE 1 An internal standard may be used to correct for transport interferences that arise from a matrix-mismatch between the calibration and sample solutions and for changes in nebuliser efficiency that can occur during analysis.

NOTE 2 An internal standard may be used to correct for differences in ionisation and sampling efficiency that can occur because of a matrix-mismatch between the calibration and sample solutions or changes in ionisation and sampling efficiency that can arise from variation in plasma conditions during analysis, e.g as a result of fluctuation in power input and/or gas flows

In order to be effective in this respect, an internal standard has to be carefully selected so that its ionisation energy is as closely matched as possible with that of each of the corresponding analytes.

NOTE 3 An internal standard may be used to correct for changes in mass response that can occur during analysis In order

to be effective in this respect, the internal standard used should have a similar mass to the analyte.

NOTE 4 In general it is preferable to match the matrix of the calibration and sample solutions rather than only relying upon the use of an internal standard to correct for interferences that can arise from a matrix-match.

Table 6 — Internal standard masses Analyte Abundance a

% natural Abundance

Internal standard masses

Decide whether it is necessary to make measurements to correct for isobaric or polyatomic interferences and, if so,

at which masses measurements are to be made Refer to Tables 5 and 6 and C.2 for information about possible interferences and how to correct for them Take account of the likely concentration of the potentially interfering elements in the sampled air If necessary, generate and apply appropriate interference correction algorithms.NOTE 1 An example of a situation where interference correction is necessary is when sampling near a cement works is performed where there could be high levels of calcium present in the air and a significant interference on nickel from calcium oxide.

NOTE 2 If the interference correction procedure described in C.2 is used it might be necessary to measure masses other than those listed in Table 5 and Table 6.

NOTE 3 Efforts should be made to determine whether polyatomic isobaric interferences exist and need to be corrected for (see also C.2.1.2).

9.5.1.4 Instrument operating parameters

Refer to the instrument manufacturer's instructions and, depending on the type and make of instrument, determinethe optimum setting for any other relevant instrument operating parameters, e.g gas flows, RF power, and sampleintroduction parameters

9.5.1.5 Matrix-matching of calibration solutions

Decide to what extent it is necessary to match the matrix of the calibration solutions with that of the samplesolutions If the sample solutions contain residue from the filter matrix it could be necessary to prepare the calibration solutions by spiking laboratory filter blank solution If it is decided to match only the acid content of thecalibration and sample solutions ensure that no filter matrix effects exist

9.5.1.6 Calibration range

Select a range of concentrations over which to prepare the calibration solutions Take into consideration the maximum air concentration of each analyte that might need to be measured, the air sample volume and the sample solution volume

9.5.2 Preparation of calibration solutions

Prepare a calibration blank solution and at least three calibration solutions from the stock standard solution(s) (see 6.5) or the working standard solution(s) (see 6.6), covering the range of calibrations selected in 9.5.1.6, matrixmatching if appropriate (see 9.5.1.5) Use freshly prepared calibration solutions unless it has been demonstrated that calibration solutions are stable for a prolonged period

9.5.3 Addition of internal standards

Add the same concentration of each of the selected internal standards (see 9.5.1.3.2) to all the solutions to be analysed, i.e to the calibration solutions, laboratory blank solutions, blank and sample solutions, interference checksolutions and quality control solutions

9.5.4 Preparing for analysis

9.5.4.1 Visual inspection

Perform a visual check to ensure that the instrument and ancillaries are in good order before commencing work.Follow the instrument manufacturer's recommendations

9.5.4.2 Setting up the instrument

Set up the ICP-MS instrument following the manufacturer's recommendations and in accordance with the methoddeveloped in 9.5.1 Wait for the instrument to warm up properly before starting work Recommended warm-uptimes, typically 30 min to 60 min, are generally provided by the instrument manufacturer Aspirate reagent blanksolution into the plasma during the instrument warm-up period since otherwise plasma conditions could be differentfrom those encountered during analysis Thoroughly optimise plasma parameters to reduce the formation ofinterfering species, e.g plasma-induced polyatomic species, doubly charged ions

9.5.4.3 Performance checks and fault diagnostics

Carry out performance checks on a daily basis to verify that the ICP-MS instrument is operating to an acceptablestandard In particular, check that the sensitivity of the instrument is within the instrument manufacturer'sspecification, that the mass response is stable across the analytical range and that oxide and doubly charged ionsare within the instrument manufacturer's specification More rigorous fault diagnostics shall be used if it issuspected that the instrument is not functioning properly Follow the instrument manufacturer's recommendations

9.5.4.4 Determination of correction factors for molecular interferences

If inter-element correction is included in the method (see 9.5.1.3.1), analyse pure solutions of interfering elements

to determine the relationships between the molecular ions which do not have isobars and their parent ions (see C.2.1.2) Enter the experimentally determined correction factors in the correction algorithms applied by the instrument software

9.5.5 Analysis

9.5.5.1 Calibration

Aspirate the calibration solutions into the plasma in order of increasing concentration and make measurements foreach solution, using the instrument's computer to generate calibration functions for the metals of interest using a linear regression Repeat the calibration if the determination coefficient for any of the metals of interest, R2, is lessthan 0,999

9.5.5.2 Measurement of samples

Make at least three replicate measurements of the reagent blank solutions, laboratory filter blank solutions, field

method detection limit the relative standard deviation of the three replicated measurements shall be less than 10 %

If this is not the case repeat the analysis and if the problem still exists check the instrumental set-up

If the concentration of any of the metals of interest in a sample solution is found to be above the upper limit of the calibration range, dilute the solution by a suitable factor, matrix-matching as necessary, and repeat the analysis.Record the dilution factor Alternatively, use the result from a suitable alternative isotope mass

9.5.5.3 Quality control measurement

Follow the quality control procedures prescribed in Clause 10

9.6 Homogeneity check for sub-samples of large filters

Perform the following homogeneity check at least once for each type of sampler where large filters are used.Determine the lead content of a number of sub-samples taken from an exposed filter using a punching tool (e.g.circular punchings of 50 mm diameter) The total filter area tested shall cover at least 30 % of the filter and the positions where sub-samples are taken shall be distributed over the entire filter area The homogeneity requirement

of 5.3.3 shall be met

NOTE Lead has been selected because, of the four analytes covered by this European Standard, it is usually present at the highest concentration in ambient air and is easily determined.

9.7 Estimation of the method detection limit and quantification limit

9.7.1 Estimate the method detection limit for each of the metals or metalloids of interest under the working

analytical conditions following the procedure described in 9.7.2 and 9.7.3, and repeat this exercise whenever theexperimental conditions are changed in a way that could affect the method detection limit

9.7.2 Prepare at least ten solutions from laboratory blank filters of the same type used for sample collection using

the sample dissolution procedure described in 9.2

9.7.3 Make measurements on the filter blank solutions (9.7.2) and calculate the method detection limit for each of

the metals of interest as described in11.5 Then calculate the method detection limits as concentrations of Pb, Cd,

As and Ni in air as described in 11.6 and compare with the requirements in 5.3.1

9.7.4 Calculate the quantification limit from the detection limit measurements according to international or national

guidelines (e.g [6], [14], [15] or [16])

10 Quality control

10.1 Calibration check

Analyse the calibration blank and at least one calibration solution after calibration and then at least every 10th

sample If the measured concentration of one of the metals of interest in the continuing calibration blank is abovethree times the instrumental detection limit (3.1 and 11.4) or if the measured concentration of one of the analytes in continuing calibration verification has changed by more than ± 10 % for GFAAS or more than ± 5 % for ICP-MS suspend analysis and recalibrate the spectrometer Reanalyse the sample solutions that were analysed during theperiod in which the sensitivity change occurred, or if this is not possible reprocess the data to take account of thesensitivity change In this case it is necessary to take account of any significant additional sources of uncertainty

10.2 Quality control solutions

Analyse suitable quality control solutions, prepared independently from calibration solutions, after calibration tomonitor the performance of the method Plot control charts and if the results indicate that the method is out ofcontrol, investigate the reasons for this, take corrective action and repeat the analysis if necessary

10.3 Recovery rate check

Separately digest and analyse at least 10 suitable portions of a CRM (6.9) before using the method in order to demonstrate the efficiency of the method The average of the recovery rates (11.7) of all portions for each analyte with respect to the certified values shall meet the requirements of 5.3.2 Check at least every six months the method recovery rate by digesting and analysing the CRM If the requirements of 5.3.2 are not met, take corrective action and repeat the recovery rate check

10.4 ICP-MS interference check

If interelement correction is included in the method (see 9.5.1.3.1), analyse an interference check solution to verify that the interelement correction procedure is being performed satisfactorily for the analytes concerned

10.5 Reagent blank check

The reagent blank check is used to check the quality of the reagents used Plot control charts and if the resultsindicate that the method is out of control, investigate the reasons for this, take corrective action and repeat theanalysis if necessary

10.6 Field filter blank check

The field filter blank is used only for quality assurance purposes If the field filter blank significantly exceeds the average laboratory filter blank (see 11.2), investigate the problem and if possible eliminate any identified sources ofcontamination If there is evidence of significant contamination, the result of the associated field samples shall berejected

10.7 External quality assessment

If laboratories carry out analysis of samples of metals in ambient air on a regular basis it is recommended that theyparticipate in a relevant external quality assessment scheme or proficiency testing scheme

10.8 Accreditation

In order to fulfil the requirement of the EU Air Quality Framework [1] the laboratories using this European Standardwill have to demonstrate to be working in accordance with the requirement of [17] One of the ways ofdemonstrating compliance with these requirements is through formal accreditation of the test described by anaccreditation body falling under the Multi-Lateral Agreement (MLA) of the European Cooperation for Accreditation (EA)

11 Calculation of results

11.1 Calculation of mass of Pb, Cd, As and Ni on the filter

Calculate the mass ma of the analyte a on the filter, in ng, using the following equation:

part

tot F a

A

A β

where

ma is the mass of the analyte a collected, in ng;

ßa is the mass concentration of analyte a in the sample solution, in ng/ml;

F is the dilution factor (F = 1 when there is no dilution of the sample solution);

Atot is the area of the exposed filter, in cm2;

Apart is the area of the digested part of the filter, in cm2

NOTE Equation 1 can be simplified for filters which are digested completely:

F a

a = β ×Vs×

Calculate the mass of the analyte a in the field filter blanks m Fa (3.1) and in the laboratory filter blanks mLa (see 3.1)

in the same way

11.2 Calculation of the average laboratory filter blank

Calculate the average laboratory filter blank (mLa ) for the analyte a as the mean value of all laboratory filter blanks

m is the average laboratory filter blank value of the analyte a (see 8.3.5), in ng;

mLa,j is the mass of the analyte a in laboratory filter blank j, in ng;

n is the number of the laboratory filter blanks

11.3 Calculation of Pb, Cd, As and Ni concentrations in ambient air

Calculate the concentration Ca of the analyte a in the sampled air, in ng/m3, by means of the following equation:

V

m m

a = −

(4)where

Ca is the mass concentration of the analyte a in the air sampled, in ng/m3;

V is the volume of air sampled, in m3

NOTE In general the concentrations are to be calculated as per the sampling conditions If it is necessary to express concentrations corrected to standard conditions, 293 K and 101,3 kPa, use the following Equation 5:

(5) where

C0,a is the mass concentration of the analyte a in the air sampled, corrected to standard conditions, in ng/m3;

P is the ambient actual pressure of the air sampled, in kPa;

T is the ambient actual temperature of the air sampled, in K

11.4 Calculation of instrumental detection limit

Calculate the standard deviation of the reagent blanks of analyte a using Equation 6:

1 n

) c c

(

2 ,

SRBa is the standard deviation of the reagent blanks of the analyte a, in ng/ml;

CRBa,i is the single value i of the reagent blank of the analyte a, in ng/ml;

RBa

c is the mean value of the reagent blank of the analyte a, in ng/ml;

n is the number of the reagent blanks

Then calculate the instrumental detection limit for analyte a using Equation 7:

RBa , ,P n f

where

DLIa is the instrumental detection limit for analyte a, in ng/ml;

tf=n-1,P=0,95 is the Student factor for nmeasurements and P = 0,95 (two-sided distribution)

11.5 Calculation of method detection limit

Calculate the standard deviation of the laboratory filter blanks using Equation 8:

1 n

) m m

(

2 ,

SLBa is the standard deviation of the laboratory filter blanks of analyte a, in ng per filter;

n is the number of the laboratory filter blanks

293

3

101

,

P C

C a = a × ×

Then calculate the method detection limit for analyte a using Equation 9:

LBa , ,P n f

where

DLMa is the detection limit of the method for analyte a, in ng per filter;

11.6 Calculation of method detection limits as concentrations of Pb, Cd, As and Ni in ambient air

Calculate the method detection limit as concentrations of Pb, Cd, As and Ni in air for an air sample volumecorresponding to a 24 h sampling period, for example, 55,2 m³ for a LVS, using Equation 10:

DLMCa is the method detection limit for analyte a, in ng/ m3;

V is the nominal air sample volume, in m3

11.7 Calculation of the recovery rates of Pb, Cd, As and Ni in CRMs

Calculate the recovery rates of Pb, Cd, As and Ni in CRMs in % using Equation 11:

100 x

Rra is the recovery rate for analyte a , in %;

xa is the mass fraction of analyte a found in the analysis of the CRM, e.g in mg/kg;

xca is the certified mass fraction of the CRM for analyte a, e.g in mg/kg.

12 Estimation of the measurement uncertainty of the method

In order to demonstrate compliance with the requirements of the 1st [2] and 4th Daughter Directives [3], the measurement uncertainty of the method, applicable in the region of the appropriate target or limit values, shall beestimated according to ENV 13005 Annex F describes a procedure for the estimation of the measurementuncertainty of the method that may be used by an individual laboratory

NOTE CR 14377 [18] describes the application of ENV 13005 in the field of “ambient air quality standards” regarding the estimation of the measurement uncertainty of the method.

13 Performance characteristics determined in field tests

13.1 General

The performance characteristics given in this clause are based upon the data gathered in the field tests carried out

to validate this method Eighty days of 24 h sampling were undertaken with eight parallel samplers at four sites in Europe At the end of the field validation, 640 filter samples were analysed and the results statistically evaluated.The characteristics of the four sites chosen were widely different (industrial, urban etc.) in order to obtain as muchinformation as possible on the performance of the method under different ambient conditions The field trials werecarried out during different seasons of the year in order to obtain information under different meteorologicalconditions

The statistical methods used and all results are described in “Statistical Evaluation of Field Test Data” [4]

NOTE The method described in this European Standard was validated using LVS-PM10 reference samplers with a flow rate of 2,3 m³/h (as described in B.1 of EN 12341:1998) Therefore all specifications (e.g performance characteristics, overall uncertainty) are given for this type of sampler

13.2 Method detection limit

Laboratory filter blanks were analysed during the field validation in order to estimate the method detection limit.The range of method detection limits obtained by the participating laboratories, calculated as described in 11.5, isgiven in Table 7, expressed as concentrations of Pb, Cd, As and Ni in air

Table 7 — Method detection limits expressed as concentrations of Pb, Cd, As and Ni in air

Range of method detection limits a