80/779/EEC - - - I
This document is meant purely as a documentation tool and the institutions do not assume any liability for its contents
COUNCIL DIRECTIVE
of 15 July 1980
on air quality limit values and guide values for sulphur dioxide and suspended particulates
(80/779/EEC)
(OJ No L 229, 30. 8. 1980, p. 30)
Amended by:
Official Journal
No page date
Council Directive of 19 October 1981 (81/857/EEC) L 319 18 7. 11. 1981Council Directive of 21 June 1989 (89/427/EEC) L 201 53 14. 7. 1989Council Directive of 23 December 1991 (91/692/EEC) L 377 48 31. 12. 1991
Amended
by:
Act of Accession of Spain and Portugal (185I) L 302 219 15. 11. 1985
Agreement on the European Economic Area (2 94 A 0103(70)) L 1 494 3. 1. 1994
80/779/EEC - - - I
ICOUNCIL DIRECTIVE
of 15 July 1980
on air quality limit values and guide values for sulphur dioxide and suspended particulates
(80/779/EEC)
THE COUNCIL OF THE EUROPEAN COMMU-
NITIES,
Having regard to the Treaty establishing the European
Economic Community, and in particular Articles 100 and
235 thereof,
Having regard to the proposal from the Commission,
Having regard to the opinion of the European Parlia-
ment(1),
Having regard to the opinion of the Economic and Social
Committee(2),
Whereas the European Communities’ programmes of ac-
tion on the environment of 1973(3)and 1977(4)provide
that priority is to be given to measures against sulphur
dioxide and suspended particulates because of their toxicity
and the current state of knowledge of their effects on
human health and the environment;
Whereas, since any discrepancy between the provisions al-
ready applicable or being prepared in the various Member
States with regard to sulphur dioxide and suspended parti-
culates could give rise to unequal conditions of competi-
tion and could consequently directly affect the functioning
of the common market, the legislative provisions in this
area should be harmonized as prescribed in Article 100 of
the T reaty;
Whereas one of the basic tasks of the European Economic
Community is to promote throughout the Community a
harmonious development of economic activities and a con-
tinued and balanced expansion; whereas such an achieve-
ment is inconceivable without measures to combat pollu-
tion, improve the quality of life and protect the
environment; whereas, since the Treaty has not providedthe necessary powers in this field, Article 235 of the T reaty
must be invoked;
Whereas, in order to protect human health in particular, it
is necessary to set for these two pollutants limit values
which must not be exceeded in the territory of the
Member States during specified periods; whereas these va-
lues should be based on the findings reached in the frame-
work of the WHO, particularly with regard to the dose/ef-
fect relationships established for sulphur dioxide and
suspended particulates taken together;
Whereas, despite the measures taken, it may not be poss-
ible to comply with these limit values in certain zones;
whereas the Member States must therefore be allowed
temporary derogations on condition that they forward to
the Commission plans for the progressive improvement of
the quality of the air in those zones;
Whereas guide values should also be set to serve as long-
term precautions for health and the environment and as
(1)OJ No C 83, 4. 4. 1977, p. 44.
(2)OJ No C 204, 30. 8. 1976, p. 34.
(3)OJ No C 112, 20. 12. 1973, p. 1.
(4)OJ No C 139, 13. 6. 1977, p. 1.
80/779/EEC - - - I
IIreference points for the establishment of specific schemes
within zones determined by the Member States;
Whereas the measures taken pursuant to this Directive
must be economically feasible and compatible with bal-
anced development;
Whereas it is necessary to establish suitable monitoring of
air quality and particularly of observance of the limit va-
lues; whereas the Member States should therefore be ob-
liged to establish measuring stations to supply the data
necessary for the application of the Directive;
Whereas since different sampling and analysis methods are
applied in the Member States, it is necessary to permit,
under certain conditions, the use of sampling and measure-
ment methods other than the reference methods laid down
in the Directive;
Whereas, since some Member States use particular
methods of sampling and analysis which cannot easily becorrelated with the reference methods, it is necessary that
the Directive specify different limit values which are to be
respected where such methods are used; whereas the
Member States concerned should also carry out parallel
measurements at a series of representative stations using
the reference methods in addition to their own methods of
measurement; whereas the Commission must make further
proposals in the light of these parallel measurements and
of the need to avoid discriminatory provisions;
Whereas the subsequent development of reference
methods of sampling and analysis referred to in this Direc-
tive may be desirable in the light of technical and scientific
progress in this area; whereas in order to facilitate imple-
mentation of the work necessary to this end, a procedure
should be set up to establish close cooperation between
the Member States and the Commission within a Commit-
tee on Adaptation to Scientific and Technical Progress,
HAS ADOPTED THIS DIRECTIVE:
80/779/EEC - - - I
1Article 1
The purpose of this Directive is to fix limit values (Annex
I) and guide values (Annex II) for sulphur dioxide and sus-
pended particulates in the atmosphere and the conditions
for their application in order to improve:
- - - the protection of human health,
- - - the protection of the environment.
Article 2
1. ‘Limit values’ means:
- - - the concentrations of sulphur dioxide and suspended
particulates considered simultaneously in accordance
with Table A in Annex I, and
- - - the concentrations of suspended particulates con-
sidered separately in accordance with Table B in
Annex I,
which, in order to protect human health in particular, must
not be exceeded throughout the territory of the Member
States during specified periods and under the conditions
laid down in the following Articles.
2. ‘Guide values’ means the concentrations of sulphur
dioxide and suspended particulates over specified periods
which are given in Annex II and are intended to serve as:
- - - long-term precautions for health and the environment,
- - - reference points for the establishment of specific
schemes within zones determined by the Member
States.
Article 3
1. Member States shall take appropriate measures to en-
sure that as from 1 April 1983 the concentrations of sul-
phur dioxide and suspended particulates in the atmosphere
are not greater than the limit values given in Annex I,
without prejudice to the following provisions.
2. Where a Member State considers that there is a li-
kelihood that, despite the measures taken, the concentra-
tions of sulphur dioxide and suspended particulates in the
atmosphere might, after 1 April 1983, exceed in certain
zones the limit values given in Annex I, it shall inform the
Commission thereof before 1 October 1982.80/779/EEC
80/779/EEC - - - I
2It shall at the same time forward to the Commission plans
for the progressive improvement of the quality of the air
in those zones. These plans, drawn up on the basis of rel-
evant information on the nature, origin and evolution of
the pollution, shall describe in particular the measures
taken or to be taken and the procedures implemented or
to be implemented by the Member State concerned. These
measures and procedures must bring the concentrations of
sulphur dioxide and suspended particulates in the atmos-
phere within these zones to values below or equal to the
limit values given in Annex I as soon as possible and by 1
April 1993 at the latest.
Article 4
1. In the zones in which the Member State concerned
considers it necessary to limit or prevent a foreseeable in-
crease in pollution by sulphur dioxide and suspended parti-
culates in the wake of development, in particular urban or
industrial development, the Member State shall, taking the
guide values in Annex II as a reference point, fix values
which must be lower than the limit values in Annex I.
2. In zones on its territory which the Member State con-
cerned considers should be afforded special environmental
protection, the Member State shall fix values which are
generally lower than the guide values in Annex II.
3. Member States shall inform the Commission of the
values, deadlines and timetables they have laid down for
the zones referred to in paragraphs 1 and 2, and of any
appropriate measures they have taken.
Article 5
In addition to the provisions referred to in Article 3 (1)
and Article 4 (1), Member States shall, with the object of
taking further precautions for the protection of health and
the environment, endeavour to move towards the guide va-
lues in Annex II wherever the measured concentrations are
higher than these values.
Article 6
Member States shall establish measuring stations designed
to supply the data necessary for the application of this Di-
rective, in particular in zones where the limit values re-
ferred to in Article 3 (1) are likely to be approached or
exceeded and in the zones referred to in Article 3 (2); the
stations must be located at sites where pollution is thoughtto be greatest and where the measured concentrations are
representative of local conditions.80/779/EEC
80/779/EEC - - - I
3Article 7
1. Following the entry into force of this Directive,
Member States shall inform the Commission, not later
than six months after the end (31 March) of the annual
reference period, of instances in which the limit values laid
down in Annex I have been exceeded and of the con-
centrations recorded.
2. They shall also notify the Commission, not later than
one year after the end of the annual reference period, of
the reasons for such instances and of the measures they
have taken to avoid their recurrence.
3. In addition, Member States shall forward information
to the Commission, at its request, on the concentrations of
sulphur dioxide and suspended particulates in any zones
they have designated pursuant to Article 4 (1) and (2).
4. The Commission shall each year communicate to theMember States the information it has received pursuant tothis Article.
Article 8
At intervals of three years the Member States shall sendinformation to the Commission on the implementation of
this Directive, in the form of a sectoral report which shall
also cover other pertinent Community Directives. This re-
port shall be drawn up on the basis of a questionnaire or
outline drafted by the Commission in accordance with the
procedure laid down in Article 6 of Directive
91/692/EEC
(5). The questionnaire or outline shall be sent
to the Member States six months before the start of the
period covered by the report. The report shall be sent to
the Commission within nine months of the end of the
three-year period covered by it.
The first report shall cover the period from 1994 to 1996
inclusive.
The Commission shall publish a Community report on the
implementation of the Directive within nine months of re-
ceiving the reports from the Member States.
Article 9
Application of the measures taken pursuant to this Direc-
tive must not bring about a significant deterioration in the
quality of the air where the level of pollution by sulphur
dioxide and suspended particulates at the time of imple-
mentation of this Directive is low in relation to the limit
values set out in Annex I.
(5)OJ No L 377, 31. 12. 1991, p. 48.80/779/EEC
91/692/EEC
80/779/EEC
91/692/EEC
80/779/EEC
80/779/EEC - - - I
4Article 10
1. For the purposes of applying this Directive, Member
States shall use either the reference methods of sampling
and analysis referred to in Annex III for sulphur dioxide
and for suspended particulates measured by the black
smoke method or in Annex IV for suspended particulates
measured by the gravimetric method, or any other method
of sampling and analysis in respect of which they demon-
strate to the Commission- at regular intervals:
— either that it ensures satisfactory correlation of results
with those obtained using the reference method,
— or that measurements taken in parallel with the refer-
ence method at a series of representative stations cho-
sen in accordance with the requirements laid down in
Article 6 show that there is a reasonably stable rela-
tionship between the results obtained using that meth-
od and those obtained using the reference method.
2. Without prejudice to the provisions of this Directive,
a Member State may also use, pending the decision of the
Council on the proposals from the Commission referred to
in paragraph 4, the sampling and analysis methods laid
down in Annex IV and the values associated with these
methods also laid down in Annex IV in substitution for the
l i m i tv a l u e ss e to u ti nA n n e xI .
3. By way of derogation from Article 3, Member Stateswhich decide to avail themselves of the provisions of para-
graph 2 shall:
— inform the Commission, before 1 January 1991, of
any zones where they consider that there is a likeli-
hood that the concentrations of sulphur dioxide and
suspended particulates in the air might exceed the
limit values set out in Annex IV after 1 January 1991,
— forward to the Commission, as from 1 April 1991,
plans for the progressive improvement of air quality
in those zones. These plans, drawn up on the basis of
relevant information on the nature, origin and devel-
opment of the pollution, shall describe in particular
the measures taken or to be taken and the procedures
implemented or to be implemented by the Member
States concerned. These measures and procedures
must bring the concentrations of sulphur dioxide and
suspended particulates in the air in these zones to val-
ues below or equal to the limit values set out in An-
nex IV as soon as possible and by l April 1993 at the
latest.80/779/EEC
89/427/EEC
80/779/EEC
89/427/EEC
80/779/EEC - - - I
54. To overcome the disadvantages of the dual approach
currently laid down in Annexes I and IV , which are not
completely equivalent, by 31 December 1992 the Commis-
sion shall submit to the Council a proposal for a general
review of this Directive. The proposal shall take account of
the experience acquired from the studies referred to in
paragraph 5 and of the results of subsequent measure-
ments taken using technical specifications or reference
methods for determining suspended particulates and sul-
phur dioxide. These technical specifications or reference
methods must be finalized by the Commission, in agree-
ment with the Member States, by 31 December 1990.
This proposal shall cover any other aspects in need of re-
view in the light of scientific knowledge and of the experi-
ence acquired over the period of application of this Direc-
tive. It shall take account of, inter alia , aspects connected
with the design of the networks for measuring air pollutionand with the installation of measuring equipment as well as
the quality and comparability of the measurements taken.
5. The Commission shall, in selected locations in theMember States and in cooperation with the latter, carry
out studies on the sampling and analysis of sulphur diox-
ide, and of black smoke and suspended particulates. These
studies shall be designed in particular to promote the har-
monization of methods of sampling and analysis of these
pollutants.
Article 11
1. Where Member States fix in border regions values for
concentrations of sulphur dioxide and suspended particu-
lates in the atmosphere in accordance with Article 4 (1)
and (2), they shall hold prior consultations. The Commis-
sion may attend such consultations.
2. Where the limit values given in Annex I or the values
referred to in Article 4 (1) and (2), inasmuch as the latter
values have been the subject of consultations in accordancewith paragraph 1, are or might be exceeded following sig-
nificant pollution which originates or may have originated
in another Member State, the Member States concerned
shall hold consultations with a view to remedying the situ-
ation. The Commission may attend such consultations.
Article 12
The procedure laid down in Articles 13 and 14 for the
adaptation on this Directive to technical progress shall
cover the subsequent development of the reference
methods of sampling and analysis referred to in Annex III.
This adaptation must not result in any direct or indirect
modification of effective concentration values given in An-
nexes I and II.89/427/EEC
80/779/EEC
80/779/EEC - - - I
6Article 13
1. For the purpose of Article 12 a Committee on the
adaptation of this Directive to scientific and technical
progress, hereinafter called ‘the Committee’, shall be set
up; it shall consist of representatives of the Member
States, with a Commission representative as chairman.
2. The Committee shall adopt its own rules of pro-
cedure.
Article 14
1. Where the procedure laid down in this Article is in-
voked, the Committee shall be convened by the chairman,
either on his own initiative or at the request of the repre-
sentative of a Member State.
2. The Commission representative shall submit a draft of
the measures to be taken to the Committee. The Commit-
tee shall give its opinion on the draft within a time limit
set by the chairman having regard to the urgency of the
matter. Decisions shall be taken by a majority of 54 votes,
the votes of the Member States being weighted as pro-
vided in Article 148 (2) of the Treaty. The chairman shall
not vote.
3. The Commission shall adopt the proposed measures if
they are consistent with the opinion of the Committee.
Where the proposed measures are not consistent with the
opinion of the Committee, or if no opinion is delivered,
the Commission shall without delay submit to the Council
a proposal on the measures to be taken. The Council shall
decide by a qualified majority.
If within three months of the proposal being submitted to
it the Council has not acted, the proposed measures shall
be adopted by the Commission.
Article 15
1. Member States shall bring into force the laws, regula-
tions and administrative provisions necessary to comply
with this Directive within 24 months of its notification and
shall forthwith inform the Commission thereof.
2. Member States shall communicate to the Commission
the texts of the provisions of national law which they adopt
in the field covered by this Directive.
Article 16
This Directive is addressed to the Member States.80/779/EEC
185I
80/779/EEC - - - I
7ANNEX I
LIMIT VALUES FOR SULPHUR DIOXIDE AND SUS-
PENDED PARTICULATES
(As measured by the black-smoke method)
TABLE A
Limit values for sulphur dioxide expressed in μg/m3with
the associated values for suspended particulates (as
measured by the black-smoke method (1)) expressed in
μg/m3
Reference periodLimit value for
sulphur dioxideAssociated value
for suspended
particulates
Year80
(median of daily
mean values
taken throughout
the year)>4 0
(median of daily
mean values
taken throughout
the year)
Year
120
(median of daily
mean values
taken throughout
the year)40
(median of daily
mean values
taken throughout
the year)
Winter
(1Octoberto31130
(median of daily
mean values
taken throughout
the winter)>6 0
(median of daily
mean values
taken throughout
the winter)
(1Octoberto31
March)180
(median of daily
mean values
taken throughout
the winter)60
(median of daily
mean values
taken throughout
the winter)
Year
(made up of units
ofmeasuring250(2)
(98 percentile of
all daily mean va-
lues taken
throughout the
year)> 150
(98 percentile of
all daily mean va-
lues taken
throughout the
year)
ofmeasur ing
periods of 24
hours)350(2)
(98 percentile of
all daily mean va-
lues taken
throughout the
year)150
(98 percentile of
all daily mean va-
lues taken
throughout the
year)80/779/EEC
80/779/EEC - - - I
8(1)The results of the measurements of black smoke taken
by the OECD method have been converted into gravi-metric units as described by the OECD (see Annex III).
(2)Member States must take all appropriate steps to ensure
that this value is not exceeded for more than three consecu-tive days. Moreover, Member States must endeavour to pre-
vent and to reduce any such instances in which this value
has been exceeded.
TABLE B
Limit values for suspended particulates (as measured by
the black-smoke method (1)) expressed in μg/m3
Reference period Limit value for suspended particulates
Year80
(median of daily mean values taken
throughout the year)
Winter
(1 October to 31
March)130
(median of daily mean values taken
throughout the winter)
Year
(made up of units of
measuring periods
of 24 hours)250(2)
(98 percentile of all daily mean values
taken throughout the year)
(1)The results of the measurements of black smoke taken by
the OECD method have been converted into gravimetricunits as described by the OECD (see Annex III).
(2)Member States must take all appropriate steps to ensurethat this value is not exceeded for more than three consecu-tive days. Moreover, Member States must endeavour to pre-vent and to reduce any such instances in which this valuehas been exceeded.80/779/EEC
80/779/EEC - - - I
9ANNEX II
GUIDE VALUES FOR SULPHUR DIOXIDE AND SUS-
PENDED PARTICULATES
(as measured by the black-smoke method)
TABLE A
(Guide values for sulphur dioxide expressed in μg/m3
Reference period Guide value for sulphur dioxide
Year40 to 60
(arithmetic mean of daily mean values
taken throughout the year)
24 hours100 to 150
(daily mean value)
TABLE B
Guide values for suspended particulates (as measured by
the black-smoke method (1)) expressed in μg/m3
Reference period Guide value for suspended particulates
Year40 to 60
(arithmetic mean of daily mean values
taken throughout the year)
24 hours100 to 150
(daily mean value)
(1)The results of the measurements of black smoke taken by
the OECD method have been converted into gravimetricunits as described by the OECD (see Annex III).80/779/EEC
80/779/EEC - - - I
10ANNEX III
REFERENCE METHODS OF SAMPLING AND ANALY-
SIS TO BE EMPLOYED WITHIN THE CONTEXT OF
THIS DIRECTIVE
A. SULPHUR DIOXIDE
The reference method of sampling for the determination
of sulphur dioxide uses the equipment described in In-
ternational Standard ISO- - -4219, first edition 1979/09/15.
The sampling period is normally 24 hours.
The reference method of analysis is that described in detail
in Annex V; it is based on Draft International Standard
ISO DP- - -6767, revised February 1979: ‘ Air quality - de-
termination of the mass concentration of sulphur dioxide
in ambient air - tetrachloromercurate (TCM)/pararosani-
line’. This method of analysis is based on the principle of
the colorimetric reaction with pararosaniline.
B. SUSPENDED PARTICULATES
For the determination of black smoke and its conversion
into gravimetric units, the method standardized by the
OECD working party on methods of measuring air pollu-
tion and survey techniques (1964) is considered to be the
reference method.
For the above-noted methods, standardized respectively by
ISO and OECD, the linguistic versions published by theseorganizations will be regarded as authentic together with
the other versions which the Commission will certify as
being in conformity therewith.80/779/EEC
80/779/EEC - - - I
11ANNEX IV
LIMIT VALUES FOR SULPHUR DIOXIDE AND SUS-
PENDED PARTICULATES (AS MEASURED BY A GRA-
VIMETRIC METHOD) APPLICABLE WITHIN THE
CONTEXT OF ARTICLE 10 (2)
TABLE A
Limit values for sulphur dioxide expressed in μg/m3,a n d
associated values for suspended particulates (measured
by the gravimetric method) expressed in μg/m3
Reference periodLimit value for sul-
phur dioxideAssociated value for
suspended particu-
lates
Year80
(median of daily
mean values
taken throughout
the year)> 150
(median of daily
mean values
taken throughout
the year)
Year
120
(median of daily
mean values
taken throughout
the year)150
(median of daily
mean values
taken throughout
the year)
Winter130
(median of daily
mean values
taken throughout
the winter)> 200
(median of daily
mean values
taken throughout
the winter)Wte
(1. 10. — 31. 3.) 180
(median of daily
mean values
taken throughout
the winter)200
(median of daily
mean values
taken throughout
the winter)80/779/EEC
89/427/EEC
80/779/EEC - - - I
12Year
(made up of units
ofmeasuring250(1)
(98th percentile
of all daily mean
values taken
throughout the
year)> 350
(98th percentile
of all daily mean
values taken
throughout the
year)
ofmeasur ing
periods of 24
hours)350(1)
(98th percentile
of all daily mean
values taken
throughout the
year)350
(98th percentile
of all daily mean
values taken
throughout the
year)
(1)Member States must take all appropriate steps to ensure
that this value is not exceeded for more than three consecu-tive days. Moreover, Member States must endeavour to pre-vent and to reduce any such instances in which this valuehas been exceeded.
TABLE B
Limit values for suspended particulates (as measured by
the gravimetric method described in (ii) below) expressed
inμg/m3
Reference period Limit value for suspended particulates
Year150
(arithmetic mean of daily mean values
taken throughout the year)
Year
(made up of units
of measuring
periods of 24
hours)300
(95 percentile of all daily mean values
taken throughout the year)
The methods of sampling and analysis applicable within
the context of Article 10 (2) are with respect to:
(i) Sulphur dioxide
— Method of sampling:
The reference method in Annex III A.
— Method of analysis: the reference method of
Annex III. The procedure set out in Article 10
(1) applies.89/427/EEC
80/779/CEE
89/427/EEC
80/779/CEE
80/779/EEC - - - I
13(ii) Suspended particulates
— Method of sampling:
1. The suspended particulates are collected on
a filter composed of either membrane or
glass-fibre.
2. The sampling system consists of:
—a f i l t e r ,
— a filter support,
—a p u m p ,
— a volumetric gasmeter.
3. The sampling system does not include a
fractionating device.
4. The sampling duration is 24 hours.
5. The filter is protected against direct deposi-
tion of particles by sedimentation and
against the direct influence of atmospheric
conditions.
6. The filters used should have an efficiency of
more than 99 % for particles having an
aerodynamic diameter of 0 3 μm.
7. The air velocity at the surface of the filter is
between 33 and 55 cm/sec inclusive. The re-
duction in the speed throughout the sampl-
ing duration must not exceed 5 % if glass-
f i b r ef i l t e r sa r eu s e do r2 5%i fm e m b r a n e
filters are used.
8. The number of samplings made throughout
the year must be at least 100, uniformly
spread throughout this period.
— Method of analysis:
( a ) A n a l y s i si sb yw e i g h i n g .
(b) 1. Membrane filters are to be condi-
tioned, before and after sampling, by
holding them at a constant temperature
between 90 and l00 ûC for two hours
and subsequently storing them in a
dessicator for two hours before weigh-
ing.
( b )2 . G l a s s - f i b r ef i l t e r sa r et ob ec o n d i -
tioned, before and after sampling, by
holding them for a period of 24 hours
in an atmosphere at 20 ûCa n d5 0 %
relative humidity before weighing.80/779/CEE
80/779/EEC - - - I
14ANNEX V
REFERENCE METHOD OF ANALYSIS FOR SULPHUR
DIOXIDE
Air quality - Determination of the mass concentration of
sulphur dioxide in ambient air - Tetrachloromercurate
(TCM)/pararosaniline method
1. SCOPE
This draft international standard specifies a spectro-
photometric method for the determination of the
mass concentration of sulphur dioxide in ambient
air. The standard comprises methods for both
sampling and analysis.
2. FIELD OF APPLICATION
With the procedure described in this standard, at-
mospheric sulphur dioxide concentrations between 7
and 1 150 μg/m3can be determined.
NoteIf higher concentrations have to be determined ali-
quots of the sample solution or smaller air samples
than specified in this standard can be taken. In this
case the absorption efficiency of the concentrations
under study.
Interferences from heavy metals, oxides of nitrogen,
ozone and reduced sulphur compounds (e.g. hy-
drogen sulphide and mercaptanes) are eliminated
or minimized. Sulphuric acid and sulphates do not
interfere. No interference of sulphur trioxide has
been experimentally ascertained, since this presuma-
bly becomes hydrated to sulphuric acid in the ab-
sorbing solution.
3. PRINCIPLE
A measured air sample is drawn through a solution
of sodium tetrachloromercurate (TCM) and the sul-
phur dioxide present in the air is absorbed by
formation of a dichlorosulphitomercurate complex.
The sample solution is treated with a solution of
sulphamic acid to destroy the nitrite anion formed
by the oxides of nitrogen present in the air. It is
then treated with solutions of formaldehyde and
acid-bleached pararosaniline containing phosphoric
a c i dt oo b t a i nap Ho f16±01 .
Pararosaniline, formaldehyde and the bisulphite
anion react to form the intensely coloured pararo-
saniline methyl sulphonic acid, which behaves as a
two-colour indicator ( λ
max = 548 nm at pH
16±01 ) .80/779/CEE
80/779/EEC - - - I
15The concentration of sulphur dioxide is taken from
a calibration graph prepared on the basis of calibra-
tion gas mixtures (6.3.1). According to the equip-
ment available in the laboratory it may be conveni-
ent in certain cases, for routine checks to replace
the calibration gas mixtures by sodium bisulphite
solutions of known concentration. However, this
procedure should only be used after a proper ca-
libration with a permeation device.
4. REAGENTS
4.1. All reagents shall be of analytical quality (pro
analysi).
Unless otherwise indicated, references to water
shall mean distilled water. The water must be free
from oxidants and should preferably be double-dis-
tilled from an all-glass apparatus.
4.2. Absorbing solution: 0 04 moles/l sodium tetrachlo-
romercurate (TCM).
Dissolve 10 9 g of mercury (II) chloride, 4 7 g of
sodium chloride and 0 07 g of ethylendiamine te-
tracetic acid disodium salt (EDTA) in water and di-
lute to 1 litre.
The solution is stable for several months and
should be discarded if a precipitate is formed.
Notes
1. The amount of EDTA added eliminates pos-
sible interferences from heavy metals up to
60μg of iron (III), 10 μg of manganese (II),
10μg of chromium (III), 10 μg of copper (II)
and 22 μg of vanadium (V) in 10 ml of absorb-
ing solution.
2. The solution is highly poisonous and should be
handled as such. A method for recovering the
mercury after the analysis is given in Annex C.
If any absorbing solution is spilt on the skin, it
must be flushed off with water immediately.
4.3. Hydrochloric acid, 1 mole/l
Dilute 86 ml of concentrated hydrochloric acid, HCl
(±=11 9g / m l ,t o1l i t r e .
4.4. Pararosaniline hydrochloride, 0 2 % stock solution
Dissolve 0 2 g of pararosaniline hydrochloride,
C19H17N3HCl in 100 ml of hydrochloric acid (4.3).80/779/CEE
80/779/EEC - - - I
16Note
Pararosaniline hydrochloride used in the prepara-
tion of the stock solution must have a purity higher
than 95 % (see Annex D) and exhibit a maximum
absorption at 540 nm in acetic acid - sodium acet-
ate buffer (0 1 moles/l). Furthermore, the absor-
bance of the reagent blank should not exceed 0 10
when the blank is prepared according to the pro-
cedure described in section 6.2.
Reagents that do not meet these requirements must
be rejected or purified. The purification can be
achieved by crystallization or extraction (see Annex
D).
4.5. Phosphoric add, 3 moles/l
Dilute 205 ml of concentrated phosphoric acid,
H3PO4,(±= 1 69 g/ml) with water to 1 litre.
4.6. Pararosaniline reagent solution
Pipet 20 ml of the pararosaniline hydrochloride
stock solution (4.4) and 25 ml of phosphoric acid
(4.5) into a 250 ml volumetric flask and make up to
the mark with water.
This reagent is stable for several months if stored
in the dark.
4.7. Formaldehyde, working solution
Pipet 5 ml of a 40 % formaldehyde solution,
HCHO, into a 1 litre volumetric flask and make up
to the mark with water. Prepare daily.
4.8. Sulphamic add, 0 6 % working solution
Dissolve 0 6 g of sulphamic acid, NH 2SO3H, in 100
ml water. This solution is stable for a few days if
protected from air.
4.9. Sodium bisulphite solution. Stock solution
Dissolve 0 3 g of sodium metabisulphite, Na 2S2O5,
in 500 ml of freshly boiled and cooled distilled
water (double-distilled water that has been deaer-
ated is preffered (SIC! preferred)). The solution
contains from 320 to 400 μg of sulphur dioxide
equivalents per millilitre. The actual concentration
is determined by adding an excess of iodine to an
aliquot of the solution and back titrating with stan-
dardized sodium thiosulphate solution (see Annex
B).
The solution is unstable.80/779/CEE
80/779/EEC - - - I
174.10. Sodium bisulphite standard solution
Immediately after the standardization of the sodium
bisulphite stock solution (4.9), pipet 2 0 ml of the
solution into a 100 ml volumetric flask and make
up to the mark with the sodium tetrachloromercu-
rate solution (4.2).
This solution is stable for 30 days if stored at 5 ûC.
Stored at room temperature, it will be stable for
one day only.
5. APP ARATUS
5.1. Sampling equipment
The equipment to be used for sampling is specified
in ISO/DIS 4219, Air Quality — Determination of
gaseous compounds in ambient air — Sampling
equipment as shown in Figure 1.
Figure 1
Block diagram of sampling equipment
> > > > >..............................
Air in-
takeParticulate
filter andfilter
holderAbsorption
bottleProtection
filterGas meter
or air-flowregulatorSampling
pump
Alternatively to the gas meter a hypodermic needle
can be used as a critical orifice in a thermostated
box. In this case, the pump must be able to reach
p
d/pu≤05 , p dand p ubeing the pressures down-
stream and upstream the needle respectively (see
5.5).
Figure 2
The equipment is shown in Figure 2.
>> > > >..............................
>
..........
>
Air in-
takeAbsorp-tionbottle Absorptionbottle Drop col-lector Pres-suremeter Criticalorifice Pres-suremeter Pump
5.2. Absorption bottles
Satisfactory absorption bottles should have an ab-
sorption efficiency for sulphur dioxide of at least
95 %. Examples of suitable absorption bottles are
g i v e ni nA n n e xA .80/779/CEE
80/779/EEC - - - I
18The absorption efficiency varies with the geometry
of the bottle, the size of the gas bubbles and their
contact time with the solution. It can be determined
by inserting a second absorption bottle in series to
the first one into the sampling system and relating
the amount of sulphur dioxide found in the first
bottle to the sum of the sulphur dioxide amount in
the two bottles. When working with midget imp-
ingers under the conditions described in section 6.1,
the absorption efficiency has been found to be
better than 98 %.
The use of mixtures of sulphur dioxide and air for
calibration, as described in clause 6.3.1, automati-
cally gives the absorption efficiency of the system.
5.3. Hydrogen sulphide absorber
A glass tube filled with quarz wool impregnated
with a solution containing 0 5 % of silver sulphate,Ag
2SO4, and 2 5 % of potassium hydrogen sul-
phate, KHSO 4. The impregnation is made by pas-
sing the solution twice through the tube and then
drying the quartz wool by heating in a nitrogen
stream.
5.4. Sample bottles
Polyethylene bottles, 100 ml, for transferring the ex-
posed absorption solutions to the laboratory.
5.5. Manometer
Two manometers accurate to 1 000 Pa, for measure-
ment of pressures when using a critical orifice in-
stead of a gas meter.
5.6. Spectrophotometer or colorimeter
A spectrophotometer or colorimeter suitable for
measuring the absorbance at about 550 nm. With a
spectrophotometer, a wavelength of 548 nm should
be used. If a colorimeter is used, the filter should
have its transmittance maximum at about 550 nm.
Reagent blank problems may occur with apparatus
having a greater spectral band width than 20 nm.
When measuring the absorbance use the same cell
for samples and standard solutions. If more than
one cell is used, the cells must be spectrophotome-
trically matched.80/779/CEE
80/779/EEC - - - I
196. PROCEDURE
6.1. Sampling
Transfer 10 ml of the TCM solution (4.2) to an ab-
sorption bottle and insert it into the sampling sys-
tem (Figure 1). Shield the absorbing solution from
direct sunlight during the sampling by covering the
absorption bottle with a suitable wrapping, such as
aluminium foil, to prevent decomposition. The dur-
ation and flow rate of the aspiration depend on the
concentration of sulphur dioxide in the air.
With midget impingers, the volume flow rate should
be between 0 5 l/min and 1 l/min. The minimum
quantity of air aspirated should be 25 litres.
T o obtain the best results, flow rate and sampling
time should be chosen to achieve an absorption of
05 t o 30 μg ( 02 t o 12 μla t2 5 ûCa n d
101 325 kPa) of sulphur dioxide per ml of absorbingsolution.
If the air is believed to contain hydrogen sulphide
this must be removed by a hydrogen sulphide ab-
sorber (5.3). Place the absorber between the parti-
culate filter and the absorption bottle.
After sampling, determine the volume of air
sampled, and note the atmospheric temperature and
pressure (7.1, Note). If the sample must be stored
for more than 24 hours before analysis, keep it at
5ûC.
Note
If the sample solution shows a precipitate, it is
probably due to the reaction of Hg II with a re-
duced sulphur compound. Remove the precipitate
by filtration or centrifugation before the analysis.
6.2. Analysis
S a m p l e sm u s tb el e f tf o ra tl e a s t2 0m i n u t e sa f t e r
sampling to allow trapped ozone to decompose.
Then transfer the sample solution quantitatively to
a 25 ml volumetric flask, using about 5 ml of water
for rinsing.
Prepare a blank by adding 10 ml of unexposed ab-
sorbing solution (4.2) to a 25 ml volumetric flask,
add the reagents as described below and read the
absorbance against distilled water using 10 mm
cells. Compare this value with the one recorded for
the blank obtained when preparing the calibration
curve. Differences of more than 10 % between the
two values indicate contamination of the distilledwater or the reagents or decomposition of the
latter, in which case fresh reagents must be pre-
pared.80/779/CEE
80/779/EEC - - - I
20Add 1 ml of the sulphamic acid solution (4.8) to
each flask and allow to react for 10 minutes to de-
stroy the nitrate from oxides of nitrogen. Then
accurately pipet 2 ml of the formaldehyde solution
(4.7) and 5 ml of the pararosaniline reagent (4.6)
into the flasks. Make up to the mark with freshly
boiled and cooled distilled water and store in a
thermostat at 20 ûC .A f t e r3 0t o6 0m i n u t e s
measure the absorbance of the sample and the
blank with distilled water in the reference cell.
Do not let the coloured solution remain in the cell
as a film of dye will then be deposited on the walls.
Note
Fixed time intervals between the addition of each
reagent e.g. one minute (SIC! reagent, e.g. one
minute,) ensure a better reproducibility of the co-
lour development.
Solutions with absorbances exceeding that of the
highest concentration used for calibration can be di-
l u t e du pt os i x f o l dw i t ht h er e a g e n tb l a n ki no r d e r
to obtain an on-scale reading. This reading, how-
ever, is only an indicative within ± 10 % of the true
absorbance value.
6.3. Calibration
6.3.1. Calibration with a mixture of sulphur dioxide and air
Mixtures of sulphur dioxide and air are prepared
according to ISO/DIS 6349.
In order to prepare the calibration graph, which is
a plot of absorbance versus sulphur dioxide con-
centration, at least four different concentration le-
vels of sulphur dioxide within the range prescribed
in section 2 are needed.
The sampling procedure and the analytical pro-
cedure as described under 6.1 and 6.2, respectively,
are applied to each of the calibration gas mixtures.
The absorbance values are plotted against the given
sulphur dioxide concentrations, and a calibration
graph is prepared.80/779/CEE
80/779/EEC - - - I
216.3.2. Calibration with sodium bisulphite solution
Pipet graduated amounts of the sodium bisulphite
standard solution (4.10), 0, 1 0, 2 0, 3 0, 4 0 and 5 0
ml, into a series of 25 ml volumetric flasks. Add
sufficient sodium tetrachloromercurate solution
(4.2) to each flask to bring the volume to approxi-
mately 10 ml. Then add the reagents as described
in 6.2. Measure the absorbances with distilled water
in the reference cell. For higher precision it is
necessary to use a constant-temperature bath. The
temperature at the calibration should not differ
from the temperature at the analysis by more than
±1ûC.
Plot the absorbances of the solutions (as ordinates)
against the microgrammes of sulphur dioxide calcu-
lated according to Annex B. A linear relationship is
obtained. The intercept with the vertical axis of theline best fitting the points is usually within 0 02 ab-
sorbance units of the blank (zero standard) reading
if 10 mm cells are used. Evaluate the calibration
factor (reciprocal of the slope of the line). This ca-
libration factor can be used for calculating the re-
sults, provided there are no radical changes in tem-
perature or pH. At least one control sample is
recommended per series of determinations to en-
sure the reliability of this factor.
7. EXPRESSION OF RESULTS
7.1. Calculation
Calculate the mass concentration of sulphur dioxide
as follows:
SO
2=f(as—ab)
V
where
SO2= mass concentration of sulphur dioxide in
micrograms per cubic metre
f = calibration factor (see 6.3.2)
as= Absorbance of the sample solution
ab= absorbance of the blank
V = volume of air sampled, in cubic metres80/779/CEE
80/779/EEC - - - I
22Note
If the mass sulphur dioxide concentration at refer-
ence conditions (25 ûC, 1 bar) is needed, the vol-
ume of air sampled, V , must be replaced by the
corresponding value of volume under reference
conditions, V R:
VR=298 V p
273+T
where
p = barometric pressure, in bar
T = Temperature of air sample, in ûC.
7.2. Detection limit
The detection limit of sulphur dioxide in 10 ml of
TCM sampling solution is between 0 2 and 1 0 μg
(based on twice the standard deviation). This corre-
sponds to mass concentrations of sulphur dioxide of
between 7 and 33 μg/m3(0 02 — 0 011 ppm) in air
sample of 30 litres (e.g. one hour sampling at 0 5 l/
min).
7.3. Precision and accuracy
The precision and accuracy of the method has not
yet been determined to any degree of certainty over
a variety of concentrations of sulphur dioxide, nor
is the absolute collection efficiency known for the
wide variety of possible systems of sampling and
testing.
The relative standard deviation of a comparable
TCM-method for replication has been found to be
17μg/m3at a concentration of 1 000 μg/m3(1).
8. LITERATURE
(1) H .C .M c K e e ,R .E .C h i l d e r s ,O .S a e n z :C o l -
laborative Study of Reference Method for De-
termination of Sulphur Dioxide in the Atmo-
sphere (Pararosaniline Method). Contract CPA
70—40, SwRI Project 21—2811. Environmen-
tal Protection Agency, Research Triangle Park,
N. C., September 1971.80/779/CEE
80/779/EEC - - - I
23ANNEX A
ABSORBER MODELS
Muenke-flask
75 ml four holes, one in bottom,
each 1 5 /Gc6Midget impinger80/779/CEE
80/779/EEC - - - I
24ANNEX B
STANDARDIZATION OF THE SODIUM BISULPHITE
STOCK SOLUTION (4.9)
B.1. Reagents
B.1.1. Iodine solution, 0 05 moles/l
Stock solution
Weigh 12 7 g of iodine, I 2, into a 250 ml beaker,
add 40 g of potassium iodide, KI, and 25 ml of
water. Stir until all is dissolved and transfer the sol-
ution quantitatively to a 1 litre volumetric flask. Di-
lute to the mark with water.
B.1.2. Iodine working solution, approximately 0 005 moles/l
Dilute 50 ml of the iodine stock solution (B.1.l) to
500 ml with water.
B.1.3. Starch indicator solution, 0 2 %
T r i t u r a t e04go fs o l u b l es t a r c ha n d00 0 2go fm e r -
cury (II) iodide, HgI 2(preservative), with a little
water, and add the paste slowly to 200 ml of boiling
water. Continue the boiling until the solution is
clear, cool and transfer to a glass stoppered bottle.
B.1.4. Sodium thiosulphate solution, approximately 0 1
moles/l
Dissolve 25 g of sodium thiosulphate,
Na2S2O35H2O, in 1 litre of freshly boiled and dis-
tilled water and add 0 1 g of sodium carbonate to
the solution. Allow the solution to stand for one
day before standardizing.
To standardize, weigh 1 5 g of potassium iodate,
KIO 3, primary standard grade, dried at 180 ûCi n t o
a 500 ml volumetric flask and dilute to the mark
with water. To a 500 ml iodine flask, pipet 50 ml of
the iodate solution. Add 2 g of potassium iodide
a n d 1 0m l o f a 1:1 0 d i l u t i o n o f c o n c e n t r a t e d h y -
drochloric acid. Stopper the flask. After five min-
utes titrate with sodium thiosulphate solution to a
pale yellow colour. Add 5 ml of the starch indicator
and complete the titration. Calculate the molarity
of the sodium thiosulphate solution, M, as follows
M=gK I O3×103×01
ml sodium thiosulphate solution ×35 67
B.1.5. Sodium thiosulphate solution, approximately 0 01
moles/l
Dilute 50 0 ml of the sodium thiosulphate solution
(B.1.4) to 500 ml with water and mix. The solution
is not stable and must be prepared fresh on the day
it is to be used by diluting the standardized sodium
thiosulphate solution (B.1.4).80/779/CEE
80/779/EEC - - - I
25B.2. Procedure
Add 25 ml of water to a 500 ml flask and pipet 50
ml of the iodine solution (B 1.2) (SIC! (B.1.2))into
the flask (here designated flask A/blank). Pipet 25
ml of the sodium bisulphite stock solution (4.9) to
a second 500 ml flask and pipet 50 ml of iodine
solution (B.1.2) into this flask (here designated B/
sample). Stopper the flasks and allow to react for
five minutes. By means of a burette containing so-
dium thiosulphate solution (B.1.5), titrate each flask
in turn to a pale yellow colour. Then add 5 ml of
starch solution (B.1.3) and continue the titration
until the blue colour disappears. Calculate the con-
centration of sulphur dioxide in the sodium bisul-
phite stock solution (4.9):
SO2(μg∕ml)=(A – B) ×M×K
V
A = volume of sodium thiosulphate solution
(B.1.5) required for the titration of the
blank, in millilitres.
B = volume of sodium thiosulphate solution
(B.1.5) required for the titration of the sam-
ple, in millilitres.
M = Molarity of the sodium thiosulphate solution
(= 0 01).
K = micro equivalent weight for sulphur dioxide
= 32 030.
V = sodium bisulphite stock solution taken, in
millilitres.
The concentration of sulphur dioxide in the bisul-
phite standard solution (4.10) is found by dividingthe result by 50.80/779/CEE
80/779/EEC - - - I
26ANNEX C
REMOVAL OF MERCURY FROM RESIDUAL SOL-
UTIONS
This Annex describes a method for the removal of mercury
from the residual solutions received when using the ab-
sorbing solution (4.2).
C.1. Reagents
C.1.1. Sodium hydroxide solution, approximately 400 g of
NaOH per litre
C.1.2. Hydrogen peroxide, H 2O2, approximately 30 %,
technical quality
C.1.3. Sodium sulphide, Na 2S9 H 2O technical quality
C.2. Procedure
Collect in a polyethylene container with a volume
of about 50 litres the residual solutions, whose mer-
cury content is too high to allow them to be dis-
carded through the sink. When the collected vol-ume reaches approximately 40 litres, add in the
following order, while stirring by means of air bub-
bling through the solution, a volume of sodium hy-
droxide solution (C.1.1) sufficient for neutralizing
followed by 400 ml more. Add 100 g of sodium
sulphide (C.1.3) and after 10 minutes, slowly 400 ml
of hydrogen peroxide solution (C.1.2).
Leave the mixture for 24 hours and then draw off
and discard the clear liquid. Transfer the residue to
another container.80/779/CEE
80/779/EEC - - - I
27ANNEX D
PROPERTIES AND PURIFICATION OF PARAROSANI-
LINE HYDROCHLORIDE
D.1. Test for the purity of the reagent
Dilute 1 ml of the PRA solution (4.4) to 100 ml
with distilled water. T ransfer 5 ml to a 50 ml volu-
metric flask and add 5 ml of a 0 1 M acetic acid-so-
dium acetate buffer solution. Dilute to the mark
with water and mix.
Wait one hour and then measure the absorbance of
the solution in a spectrophotometer at 540 nm in a
10 mm cell.
Calculate the concentration of pararosaniline (PRA)
as follows:
%P R A =absorbance ×K
100 mg
where:
K = 21 300.
If the purity of the pararosaniline is below 95 %,
the reagent must be purified by one of the pro-
cedures described in D.2 and D.3.
D.2. Purification by extraction
In a 250 ml separatory funnel, equilibrate 100 ml
e a c h o f 1 - - - b u t a n o l a n d 1MH C l . W e i g h 01g o f
pararosaniline hydrochloride (PRA) into a beaker.
Add 50 ml of the equilibrated acid and let stand
for several minutes. Add 50 ml of the equilibrated
1- - -butanol to a 125 ml separatory funnel. Transfer
the acid solution containing the dye to the funnel
and extract. The violet impurity will transfer to the
organic phase. Transfer the lower (aqueous) phaseinto another separatory funnel and add 20 ml por-
tions of 1- - -butanol. This is usually sufficient to re-
move almost all the violet impurity which contrib-
utes to the reagent blank. If the violet impurity still
appears in the 1- - -butanol phase after five extrac-
tions, discard this batch of dye.
After the final extraction, filter the aqueous phase
through a cotton plug into a 50 ml volumetric flask
arid bring to volume with 1 M HCl. This stock re-
agent will be yellowish red.80/779/CEE
80/779/EEC - - - I
28Note
Certain batches of 1- - -butanol contain oxidants that
create a sulphur dioxide demand. Check by shaking
20 ml of 1- - -butanol with 5 ml of a 15 % potas-
sium-iodide solution. If a yellow colour appears in
the alcohol phase, redistill the 1- - -butanol from
silver oxide.
D.3. Purification by recrystal1ization
Dissolve 1 g of pararosaniline hydrochloride in 250
ml of 2 5 M hydrochloric acid. Let the solution
stand for two hours at room temperature. After
filtration, the pararosaniline is reprecipitated by
addition of a small excess of 2 5 M sodium hydrox-
ide solution.
Collect the precipitate on a filter funnel (porosity
3). The filtrate should be colourless. Wash the pre-
cipitate with distilled water to remove excess so-dium hydroxide and the sodium chloride formed.
Dissolve the precipitate in 70 ml of methanol
heated to boiling and finally add 300 ml of water at
80ûC. Let the solution stand at room temperature.
T h ep a r a r o s a n i l i n er e p r e c i p i t a t e ss l o w l y .T h ey i e l d
of recrystallization is about 64 %. Pararosaniline
gets dark between 200 and 205 ûCa n dd e c o m p o s e s
at 285 ûC.
Literature
H. G. C. King and U. G. Pruden: The determina-
tion of sulphur dioxide with rosaline dyes. Analyst
94, 43—48 (1969).80/779/CEE