
1 

(1) These Regulations may be cited as the Air Quality Limit Values Regulations 2001 and shall come into force on 19th July 2001.
(2) With the exception of regulation 10 which shall apply to the whole of the United Kingdom, these Regulations shall apply to England only.
2 
In these Regulations—
 “agglomeration” means a zone with a population concentration in excess of 250,000 inhabitants, or, where the population concentration is 250,000 inhabitants or less, a population density per km 2 for which the Secretary of State considers that the need for ambient air to be assessed or managed is justified;
 “alert threshold” has the meaning given by regulation 8(2);
 “ambient air” means outdoor air in the troposphere, excluding work places;
 “assessment” means any method used to measure, calculate, predict or estimate the level of a relevant pollutant in the ambient air;
 “fixed measurements” means measurements taken at fixed sites either continuously or by random sampling, the number of measurements being sufficiently large to enable the levels observed to be determined;
 “level” means the concentration of a relevant pollutant in ambient air;
 “limit value” has the meaning given in regulation 3(1);
 “lower assessment threshold” has the meaning given in regulation 5(5);
 “natural events” means volcanic eruptions, seismic activities, geothermal activities, wild-land fires, high-wind events or the atmospheric resuspension or transport of natural particles from dry regions;
 “oxides of nitrogen” means the sum of nitric oxide and nitrogen dioxide added as parts per billion and expressed as nitrogen dioxide in microgrammes per cubic metre;
 “PM2.5” means particulate matter which passes through a size-selective inlet with a 50% efficiency cut-off at 2.5 μm aerodynamic diameter;
 “PM10” means particulate matter which passes through a size-selective inlet with a 50% efficiency cut-off at 10 μm aerodynamic diameter;
 “relevant pollutants” means sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead;
 “upper assessment threshold” has the meaning given in regulation 5(5); and
 “zone” means a part of the territory of England shown on a map published by the Secretary of State on 19th January 2001, deposited at the offices of the Department for Environment, Food and Rural Affairs, Ashdown House, 123 Victoria Street, London SW1E 6DE and displayed on the Department’s website at http://www.environment.detr.gov.uk.
3 

(1) The Secretary of State shall take the measures necessary to ensure that throughout England in each zone concentrations of relevant pollutants in ambient air, as assessed in accordance with regulations 4 to 7, do not exceed the limit values set out in Schedule 1 from the dates specified in that Schedule.
(2) The measures taken shall—
(a) take into account an integrated approach to the protection of air, water and soil;
(b) not contravene Community legislation on the protection of safety and health of workers at work; and
(c) have no significant negative effects on the environment in the other Member States.
4 
The Secretary of State shall ensure that ambient air quality is assessed in each zone in relation to each of the relevant pollutants in accordance with regulations 5 to 7.
5 

(1) The Secretary of State shall classify each zone in relation to each of the relevant pollutants according to whether ambient air quality in that zone for that pollutant is required to be assessed by—
(a) measurements;
(b) a combination of measurements and modelling techniques; or
(c) by the sole use of modelling or objective estimation techniques.
(2) Measurements must be used to assess ambient air quality in relation to a relevant pollutant in a zone if—
(a) the zone is an agglomeration;
(b) the levels of that pollutant in the zone are between the relevant limit values and upper assessment thresholds; or
(c) the levels of that pollutant in the zone exceed the limit values for that pollutant.
(3) A combination of measurements and modelling techniques may be used to assess ambient air quality in any zone in relation to a relevant pollutant where the levels of that pollutant over a representative period are below the relevant upper assessment thresholds.
(4) Where the levels of a relevant pollutant in any zone over a representative period are below the relevant lower assessment thresholds, the sole use of modelling or objective estimation techniques for assessing levels of that pollutant is permissible unless—
(a) the zone is an agglomeration; and
(b) the pollutant being assessed is sulphur dioxide or nitrogen dioxide.
(5) The upper and lower assessment thresholds for the relevant pollutants shall be determined in accordance with Schedule 2.
(6) Where a zone is classified in relation to a pollutant under paragraph (1)(a), modelling techniques may be used for supplementing the measurements taken in order to provide an adequate level of information on ambient air quality in relation to a relevant pollutant in a zone.
(7) The Secretary of State may also designate a zone classified under this regulation in relation to a relevant pollutant as follows.
(8) Where the relevant pollutant is sulphur dioxide, the zone may be designated under this paragraph if the limit values are exceeded in the zone owing to concentrations of sulphur dioxide in ambient air due to natural sources.
(9) Where the relevant pollutant is PM10, the zone may be designated—
(a) under this sub-paragraph if due to natural events concentations of PM10 in the ambient air are significantly in excess of normal background levels from natural sources;
(b) under this sub-paragraph if due to the resuspension of particulates following the winter sanding of roads concentrations of PM10 in the ambient air are significantly in excess of normal background levels from natural sources.
6 

(1) The Secretary of State shall review the classification of each zone under regulation 5 at least once in every five years in accordance with Part II of Schedule 2.
(2) The Secretary of State shall also review the classification of any zone under regulation 5 in the event of significant changes in activities affecting ambient concentrations in that zone of any of the relevant pollutants.
(3) In this paragraph, ‘classification’ includes any designation under regulation 5(7) to (9).
7 

(1) The Secretary of State shall ensure that ambient air quality is assessed in each zone by following the appropriate method for each relevant pollutant in accordance with its current classification.
(2) Where a zone is classified under regulation 5(1)(a) or (b) in relation to a relevant pollutant—
(a) measurements of that pollutant must be taken at fixed sites either continuously or by random sampling; and
(b) the number of measurements must be sufficiently large to enable the levels of that pollutant to be properly determined.
(3) Schedule 3 shall have effect for the purposes of determining the location of sampling points for the relevant pollutants.
(4) For each zone classified under regulation 5(1)(a) in relation to a relevant pollutant, the Secretary of State shall ensure that the minimum number of fixed sampling points determined in accordance with Schedule 4 is used for sampling the concentrations of that pollutant in that zone.
(5) For each zone classified under regulation 5(1)(b) in relation to a relevant pollutant, the Secretary of State shall ensure that the number of fixed sampling points used for sampling that pollutant in that zone, and the spatial resolution of other techniques, shall be sufficient for the concentrations of that pollutant to be established in accordance with Part I of Schedule 3 and Part I of Schedule 5.
(6) Reference methods for—
(a) the analysis of sulphur dioxide, nitrogen dioxide and oxides of nitrogen;
(b) the sampling and analysis of lead; and
(c) the sampling and measurement of PM10,
are set out in Schedule 6 and these methods must be used unless other methods are used which the Secretary of State considers can be demonstrated to give equivalent results.
(7) The Secretary of State shall ensure that—
(a) measuring stations to supply representative data on concentrations of PM2.5 are installed and operated using methods for the sampling and measurement of PM2.5 that she considers suitable; and
(b) sampling points for PM2.5 are, where possible, co-located with sampling points for PM10.
(8) For zones which are classified under regulation 5(1)(b) or (c), the Secretary of State shall ensure that the information set out in Part II of Schedule 5 is compiled.
(9) For sulphur dioxide, nitrogen dioxide and oxides of nitrogen measurements of volume must be standardised at a temperature of 293°K and a pressure of 101,3 kPa.
8 

(1) The Secretary of State shall draw up action plans indicating the measures to be taken in the short term where there is any risk of the limit values for any of the relevant pollutants, or the alert thresholds for sulphur dioxide or nitrogen dioxide, being exceeded, in order to reduce that risk and to limit the duration of such an occurence.
(2) The alert threshold for sulphur dioxide is set out in paragraph 1.2 of Part I of Schedule 1 and the alert threshold for nitrogen dioxide is set out in paragraph 2.2 of Part II of Schedule 1.
9 

(1) The Secretary of State shall draw up a list of zones in which the levels of one or more of the relevant pollutants are higher than—
(a) in a case where there is no margin of tolerance shown in Schedule 1 in relation to a limit value, the limit value;
(b) in any other case, the limit value plus the margin of tolerance shown in Schedule 1.
(2) The Secretary of State shall draw up a list of zones in which the levels of one or more of the relevant pollutants are between the limit value and the limit value plus any margin of tolerance.
(3) Subject to paragraphs (6), (8) and (9), the Secretary of State shall draw up for each zone listed under paragraph (1) a plan or programme for attaining the limit values for the pollutants in question within the time limits specified in Schedule 1 and shall ensure that the plan or programme is implemented.
(4) The plan or programme shall at least include the information listed in Schedule 7.
(5) Where in any zone the level of more that one pollutant is higher than the limit values, an integrated plan covering all the pollutants in question shall be prepared.
(6) For any zone designated under regulation 5(8), the Secretary of State may provide that plans or programmes shall only be required under this regulation where the limit values are exceeded owing to man-made emissions.
(7) Plans or programmes for PM10 which are prepared in accordance with this regulation shall also have the aim of reducing concentrations of PM2.5.
(8) For any zone designated under regulation 5(9)(a), the Secretary of State may provide that plans or programmes shall only be required where the limit values are exceeded owing to causes other than natural events.
(9) For any zone designated under regulation 5(9)(b), the Secretary of State may provide that plans or programmes shall only be required where the limit values are exceeded owing to PM10 levels other than those caused by winter road sanding.
10 

(1) For the purpose of this regulation, a transboundary pollution issue arises when in any part of the United Kingdom the level of a relevant pollutant exceeds, or is likely to exceed, the limit value plus the margin of tolerance or, as the case may be, the alert threshold following significant pollution in another Member State of the European Union.
(2) It shall be the duty of the relevant administration to notify the Secretary of State of any transboundary pollution issue affecting Wales, Scotland or Northern Ireland.
(3) The Secretary of State shall consult any other Member State directly concerned with a pollution issue with a view to finding a solution to that issue—
(a) when she considers that a transboundary pollution issue has arisen affecting England;
(b) on receiving a notification under paragraph (2); or
(c) on being notified by any other Member State that the limit value or alert threshold for any relevant pollutant may be exceeded in that Member State as a result of pollution originating in any part of the United Kingdom.
(4) In any case which appears to her to affect Wales, Scotland or Northern Ireland respectively, the Secretary of State shall—
(a) inform the relevant administration of any notification made under paragraph (3)(c); and
(b) consult the relevant administration about any action which she proposes to take.
(5) The Commission may be present at any consultations conducted under paragraph (3).
(6) In this regulation, ‘relevant administration’ means—
(a) the National Assembly for Wales for matters affecting Wales;
(b) Scottish Ministers for matters affecting Scotland; and
(c) Northern Ireland Ministers for matters affecting Northern Ireland.
11 

(1) For the purposes of the implementation of any obligations of the United Kingdom under Council Directive 96/62/EC on ambient air quality assessment and management and Council Directive 99/30/EC relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air—
(a) the Secretary of State shall have the same power to give directions to local authorities in Greater London and the Mayor of London; and
(b) the Mayor of London shall have the same power to give directions to local authorities in Greater London,
as the Secretary of State has under section 85(5) of the Environment Act 1995 in relation to local authorities in England outside Greater London.
(2) The provisions of subsections (6), (6A) and (7) of section 85 of the Environment Act 1995 shall apply to directions given under this regulation as they apply to directions given under that section, and in the case of subsection (7) as if the Mayor of London were a local authority.
12 

(1) The Secretary of State shall draw up a list of zones in which the levels of the relevant pollutants are below the limit values.
(2) The Secretary of State shall ensure that the levels of the relevant pollutants in these zones are maintained below the limit values and shall endeavour to preserve the best ambient air quality compatible with sustainable development.
13 

(1) The Secretary of State shall ensure that up-to-date information on ambient concentrations of each of the relevant pollutants is routinely made available to the public.
(2) Information on ambient concentations of sulphur dioxide, nitrogen dioxide and particulate matter shall be updated—
(a) in the case of hourly values for sulphur dioxide and nitrogen dioxide, where practicable on an hourly basis;
(b) in all other cases, as a minimum on a daily basis.
(3) Information on ambient concentrations of lead shall be updated on a three-monthly basis.
(4) Information made available under paragraph (1) shall include—
(a) an indication of the extent to which limit values and alert thresholds for relevant pollutants have been exceeded over the averaging periods specified in Schedule 1; and
(b) a short assessment of those exceedances and their effects on health.
(5) When an alert threshold is exceeded, the Secretary of State shall ensure that the necessary steps are taken to inform the public, and the information made available shall as a minimum include the information specified in paragraphs 1.3 of Part I and 2.3 of Part II of Schedule 1.
(6) Information to be made available to the public under this regulation shall include the map mentioned in the definition of “zone” in regulation 2 and action plans, plans and programmes prepared under regulations 8 and 9 respectively.
(7) For the purposes of this regulation, the public includes, but is not limited to, health care bodies and organisations having an interest in ambient air quality and representing the interests of sensitive populations, consumers and the environment.
(8) Information made available under this regulation shall be clear, comprehensible and accessible.
14 

(1) The Air Quality Standards Regulations 1989, insofar as they apply to England, are hereby revoked as follows.
(2) Regulation 2(1) (limit values for sulphur dioxide and suspended particulates) and regulation 4(1) (limit value for lead in air) shall be revoked with effect from 1st January 2005.
(3) Regulations 3 (measurement of sulphur dioxide and suspended particulates), 5 (measurement of lead in air) and 7 (measurement of nitrogen dioxide in the atmosphere) shall be revoked.
(4) Regulation 6 (limit value for nitrogen dioxide in the atmosphere) shall be revoked with effect from 1st January 2010.
(5) From 19th July 2001 until 1st January 2005, if the methods prescribed by these regulations for the assessment of suspended particulate matter are used for the purpose of demonstrating compliance with Annex IVDirective 80/779/EEC of 15th July 1980 on air quality limit values and guide values for suspended particulates, the data so collected shall be multiplied by a factor of 1.2.
Signed by authority of the Secretary of State for Environment, Food and Rural Affairs
Michael Meacher
Minister of State
Department for Environment, Food and Rural Affairs
25th June 2001
SCHEDULE 1
Regulations 3(1), 8(2), 9(1) and (3), 13(4) and (5)
PART I
1.1 


 Averaging period Limit value Margin of tolerance Date by which limit value is to be met

1 
Hourly limit value for the protection of human health 1 hour 350 μg/m3, not to be exceeded more than 24 times a calendar year 120 μg/m3 on 19th July 2001, reducing on 1st January of each following year by equal annual amounts to reach 0 μg/m3 by 1st January 2005 1st January 2005

2 
Daily limit value for the protection of human health 24 hours 125 μg/m3, not to be exceeded more than 3 times a calendar year None 1st January 2005

3 
Limit value for the protection of ecosystems Calendar year and winter (1st October to 31st March) 20 μg/m3 None 19th July 2001
1.2 
500 μg/m3 measured over three consecutive hours at locations representative of air quality over at least 100 km2 or an entire zone, whichever is the smaller.
1.3 
Details to be made available to the public should include at least:
— the date, hour and place of the occurrence and the reasons for the occurrence, where known;
— any forecasts of:
— changes in concentration (improvement, stabilisation, or deterioration), together with the reasons for those changes,
— the geographical area concerned,
— the duration of the occurrence;
— the type of population potentially sensitive to the occurrence;
— the precautions to be taken by the sensitive population concerned.
PART II
2.1 


 Averaging period Limit value Margin of tolerance Date by which limit value is to be met

1 
Hourly limit value for the protection of human health 1 hour 200 μg/m3 NO2, not to be exceeded more than 18 times a calendar year 90 μg/m3 on 19th July 2001, reducing on 1st January of each following year by equal annual amounts to reach 0 μg/m3 by 1st January 2010 1st January 2010

2 
Annual limit value for the protection of human health Calendar year 40 μg/m3 NO2 18 μg/m3 on 19th July 2001, reducing on 1st January of each following year by equal annual amounts to reach 0 μg/m3 by 1st January 2010 1st January 2010

3 
Annual limit value for the protection of vegetation Calendar year 30 μg/m3 NOx None 19th July 2001
2.2 
400 μg/m3 measured over three consecutive hours at locations representative of air quality over at least 100 km2 or an entire zone or agglomeration, whichever is the smaller.
2.3 
Details to be made available to the public should include at least:
— the date, hour and place of the occurrence and the reasons for the occurrence, where known;
— any forecasts of:
— changes in concentration (improvement, stabilisation, or deterioration), together with the reasons for those changes,
— the geographical area concerned,
— the duration of the occurrence;
— the type of population potentially sensitive to the occurrence;
— the precautions to be taken by the sensitive population concerned.
PART III

 Averaging period Limit value Margin of tolerance Date by which limit value is to be met

1 
24-hour limit value for the protection of human health 24 hours 50 μg/m3 PM10, not to be exceeded more than 35 times a calendar year 20 μg/m3 on 19th July 2001, reducing on 1st January of each following year by equal annual amounts to reach 0 μg/m3 by 1st January 2005 1st January 2005

2 
Annual limit value for the protection of human health Calendar year 40 μ g/m3 PM10 6.4 μg/m3 on 19th July 2001, reducing on 1st January of each following year by equal annual amounts to reach 0 μg/m3 by 1st January 2005 1st January 2005
PART IV

 Averaging period Limit value Margin of tolerance Date by which limit value is to be met
Annual limit value for the protection of human health Calendar year 0.5 μg/m3 0.4 μg/m3 on 19th July 2001, reducing on 1st January of each following year by equal annual amounts to reach 0 μg/m3 by 1st January 2005 1st January 2005
SCHEDULE 2
Regulations 5(5) and 6(1)
PART I
The following upper and lower assessment thresholds will apply:

(a)
 Health protection Ecosystem protection
Upper assessment threshold 60% of 24-hour limit value (75 μg/m3), not to be exceeded more than 3 times in any calendar year 60% of winter limit value (12 μg/m3)
Lower assessment threshold 40% of 24-hour limit value (50 μg/m3), not to be exceeded more than 3 times in any calendar year 40% of winter limit value (8 μg/m3)

(b)
 Hourly limit value for the protection of human health (NO2) Annual limit value for the protection of human health (NO2) Annual limit value for the protection of vegetation (NOx)
Upper assessment value 70% of limit value (140 μg/m3), not to be exceeded more than 18 times in any calendar year 80% of limit value (32 μg/m3) 80% of limit value (24 μg/m3)
Lower assessment value 50% of limit value (100 μg/m3), not to be exceeded more than 18 times in any calendar year 65% of limit value (26 μg/m3) 65% of limit value (19.5 μg/m3)

(c)
 24-hour average Annual average 
Upper assessment threshold 60% of limit value (30 μg/m3), not to be exceeded more than seven times in any calendar year 70% of limit value (14 μg/m3)
Lower assessment threshold 40% of limit value (20 μg/m3), not to be exceeded more than seven times in any calendar year 50% of limit value (10 μg/m3)

(d)
 Annual average
Upper assessment threshold 70% of limit value (0.35 μg/m3)
Lower assessment threshold 50% of limit value (0.25 μg/m3)

PART II
Exceedances of upper and lower assessment thresholds must be determined on the basis of concentrations during the previous five years where sufficient data are available. An assessment threshold will be deemed to have been exceeded if during those five years the total number of exceedances of the numerical concentration of the threshold is more than three times the number of exceedances allowed each year.

Where fewer than five years' data are available, measurement campaigns of short duration during the period of the year and at locations likely to be typical of the highest pollution levels may be combined with results obtained from emisson inventories and modelling to determine exceedances of the upper and lower assessment thresholds.

SCHEDULE 3
Regulations 7(3) and 7(5)
The following considerations will apply to fixed measurement.

PART I

(a) Protection of human health

Sampling points directed at the protection of human health should be sited:
(i) to provide data on the areas within zones where the highest concentrations occur to which the population is likely to be directly or indirectly exposed for a period which is significant in relation to the averaging period of the limit value(s);
(ii) to provide data on levels in other areas within the zones which are representative of the exposure of the general population.

Sampling points should in general be sited to avoid measuring very small micro-environments in their immediate vicinity. As a guideline, a sampling point should be sited to be representative of air quality in a surrounding area of no less than 200 m2 at traffic-orientated sites and of several square kilometres at urban-background sites.

Sampling points should also, where possible, be representative of similar locations not in their immediate vicinity.

Account should be taken of the need to locate sampling points on islands, where that is necessary for the protection of human health.
(b) Protection of ecosystems and vegetation

Sampling points targeted at the protection of ecosystems or vegetation should be sited more than 20 km from agglomerations or more than 5 km from other built-up areas, industrial installations or motorways. As a guideline, a sampling point should be sited to be representative of air quality in a surrounding area of at least 1000 km2. A sampling point may be sited at a lesser distance or to be representative of air quality in a less extended area, taking account of geographical conditions.

Account should be taken of the need to assess air quality on islands.

PART II
The following guidelines should be met as far as practicable:
— the flow around the inlet sampling probe should be unrestricted without any obstructions affecting the airflow in the vicinity of the sampler (normally some metres away from buildings, balconies, trees and other obstacles and at least 0.5 m from the nearest building in the case of sampling points representing air quality at the building line);
— in general, the inlet sampling point should be between 1.5 m (the breathing zone) and 4 m above the ground. Higher positions (up to 8 m) may be necessary in some circumstances. Higher siting may also be appropriate if the station is representative of a large area;
— the inlet probe should not be positioned in the immediate vicinity of sources in order to avoid the direct intake of emissions unmixed with ambient air;
— the sampler’s exhaust outlet should be positioned so that recirculation of exhaust air to the sampler inlet is avoided;
— location of traffic-orientated samplers;
— for all pollutants, such sampling points should be at least 25 m from the edge of major junctions and at least 4 m from the centre of the nearest traffic lane,
— for nitrogen dioxide, inlets should be no more than 5 m from the kerbside,
— for particulate matter and lead, inlets should be sited so as to be representative of air quality near to the building line.

The following factors may also be taken into account:
— interfering sources;
— security;
— access;
— availability of electrical power and telephone communications;
— visibility of the site in relation to its surroundings;
— safety of public and operators;
— the desirability of co-locating sampling points for different pollutants;
— planning requirements.

PART III
The site-selection procedures should be fully documented at the classification stage by such means as compass-point photographs of the surrounding area and a detailed map. Sites should be reviewed at regular intervals with repeated documentation to ensure that selection criteria remain valid over time.

SCHEDULE 4
Regulation 7(4)
PART I

(a) Diffuse sources 

Population of zone (thousands) If concentrations exceed the upper assessment threshold If maximum concentrations are between the upper and lower assessment thresholds For SO2 and NO2 in agglomerations where maximum concentrations are below the lower assessment thresholds
0 –250 1 1 not applicable
250 –499 2 1 1
500 –749 2 1 1
750 –999 3 1 1
1,000 –1,499 4 2 1
1,500 –1,999 5 2 1
2,000 –2,749 6 3 2
2,750 –3,749 7 3 2
3,750 –4,749 8 4 2
4,750 –5,999 9 4 2
>6,000 10 5 3
 For NO2 and particulate matter: to include at least one urban-background station and one traffic-orientated station  


(b) Point sources

For the assessment of pollution in the vicinity of point sources, the number of sampling points for fixed measurement should be calculated taking into account emission densities, the likely distribution patterns of ambient-air pollution and the potential exposure of the population.

PART II

If maximum concentrations exceed the upper assessment threshold If maximum concentrations are between the upper and lower assessment thresholds
1 station every 20,000 km2 1 station every 40,000 km2
In island zones the number of sampling points for fixed measurement should be calculated taking into account the likely distribution patterns of ambient-air pollution and the potential exposure of ecosystems or vegetation.
SCHEDULE 5
Regulation 7(5) and (8)
PART I
The following data-quality objectives for the required accuracy of assessment methods, of minimum time coverage and of data capture of measurement are laid down to guide quality-assurance programmes.

 Suphur dioxide, nitrogen dioxide and oxides of nitrogen Particulate matter and lead
Continuous measurement  
Accuracy 15% 25%
Minimum data capture 90% 90%
Indicative measurement  
Accuracy 25% 50%
Minimum data capture 90% 90%
Minimum time coverage 14% (One measurement a week at random, evenly distributed over the year, or eight weeks evenly distributed over the year.) 14% (One measurement a week at random, evenly distributed over the year, or eight weeks evenly distributed over the year.)
Modelling  
Accuracy:  

 Hourly averages 50%–60% 

 Daily averages 50% 

 Annual averages 30% 50%
Objective estimation
 
Accuracy: 75% 100%

The accuracy of the measurement is defined as laid down in the ‘ Guide to the Expression of Uncertainty of Measurements ’ (ISO 1993) or in ISO 5725-1 ‘ Accuracy (trueness and precision) of measurement methods and results ’ (ISO 1994). The percentages in the table are given for individual measurements averaged, over the period considered, by the limit value, for a 95% confidence interval (bias + two times the standard deviation). The accuracy for continuous measurements should be interpreted as being applicable in the region of the appropriate limit value.

The accuracy for modelling and objective estimation is defined as the maximum deviation of the measured and calculated concentration levels, over the period considered by the limit value, without taking account the timing of the events.

The requirements for minimum data capture and time coverage do not include losses of data due to the regular calibration or the normal maintenance of the instrumentation.

The Secretary of State may allow for random measurements to be made instead of continuous measurements for particulate matter and lead by methods for which accuracy within the 95% confidence interval with respect to continuous monitoring has been demonstrated to be within 10%. Random sampling must be spread evenly over the year.

PART II
The following information should be compiled for zones within which sources other than measurement are employed to supplement information from measurement or as the sole means of air quality assessment:
— a description of assessment activities carried out;
— the specific methods used, with references to descriptions of the method;
— the sources of data and information;
— a description of results, including accuracies and, in particular, the extent of any area or, if relevant, the length of road within the zone over which concentrations exceed limit value(s) or, as may be, limit value(s) plus applicable margin(s) of tolerance and of any area within which concentrations exceed the upper assessment threshold or the lower assessment threshold;
— for limit values the object of which is the protection of human health, the population potentially exposed to concentrations in excess of the limit value.

Where possible maps shall be compiled showing concentration distributions within each zone.

SCHEDULE 6
Regulation 7(6)
PART I
ISO/FDIS 10498 (Standard in draft) Ambient air—determination of sulphur dioxide—ultraviolet fluorescence method.

PART II
ISO 7996: 1985 Ambient air—determination of the mass concentrations of nitrogen oxides—chemiluminescence method.

PART IIIA
The reference method for the sampling of lead will be that described in the Annex to Directive 82/884/EEC until such time as the limit value in Schedule 1 to these Regulations is to be met, when the reference method will be that for PM10 specified in Part IV of this Schedule.

PART IIIB
ISO 9855: 1993 Ambient air—Determination of the particulate lead content of aerosols collected in filters. Atomic absorption spectroscopy method.

PART IV
The reference method for the sampling and measurement of PM10 will be that described in EN 12341 ‘ Air Quality—Field Test Procedure to Demonstrate Reference Equivalence of Sampling Methods for the PM10 fraction of particulate matter ’. The measurement principle is based on the collection on a filter of the PM10 fraction of ambient particulate matter and the gravimetric mass determination.

SCHEDULE 7
Regulation 9(4)
1 
Localisation of excess pollution
— region
— city (map)
— measuring station (map, geographical coordinates).
2 
General information
— type of zone (city, industrial or rural area)
— estimate of the polluted area (km2) and of the population exposed to the pollution
— useful climatic data
— relevant data on topography
— sufficient information on the type of targets requiring protection in the zone.
3 
Responsible authorities
 Names and addresses of persons responsible for the development and implementation of improvement plans.
4 
Nature and assessment of pollution
— concentrations observed over previous years (before the implementation of the improvement measures)
— concentrations measured since the beginning of the project
— techniques used for the assessment.
5 
Origin of pollution
— list of the main emission sources responsible for pollution (map)
— total quantity of emissions from these sources (tonnes/year)
— information on pollution imported from other regions.
6 
Analysis of the situation
— details of those factors responsible for the excess (transport, including cross-border transport, formation)
— details of possible measures for improvement of air quality.
7 
Details of those measures or projects for improvement which existed prior to 21st November 1996
— local, regional, national, international measures
— observed effects of these measures.
8 
Details of those measures or projects adopted with a view to reducing pollution following 21st November 1996
— listing and description of all the measures set out in the project
— timetable for implementation
— estimate of the improvement of air quality planned and of the expected time required to attain these objectives.
9 
Details of the measures or projects planned or being researched for the long term.
10 
List of the publications, documents, work etc used to supplement information requested in this Schedule.