Appendix 3 Article 5 Assessment of Ozone

As part of the proposed European Directive relating to ozone in ambient air, a requirement will be placed upon member states to establish adequate information on ambient levels of ozone. In accordance with Article 5 of the Framework Directive, a further requirement is placed on member states to undertake preliminary investigation of the ambient levels of pollutants prior to the implementation of related Daughter Directives.

The objectives of these assessments are to establish estimates for the overall distribution and levels of pollutants, and to identify additional monitoring requirements, which may be necessary in order to fulfil obligations under the Framework and Daughter Directives. In this report, observations and recommendations are raised regarding the number of additional monitoring locations, which may be required for ozone. Estimated cost data for these additional monitoring requirements are also presented.

Methodology

For the purpose of this assessment, the UK has been divided into 16 zones, based on official government office boundaries within England and boundaries provided or authorised by the relevant offices within Scotland, Wales and Northern Ireland as part of the Article 5 Assessment performed for the first Daughter Directive on NO₂, SO₂, PM10 and lead. A further 28 agglomeration zones (areas of urban population > 250000) have also been agreed based on DETR GIS information for England and Wales, localities information in Scotland and CORINE land cover information within Northern Ireland. Monitoring requirements within each zone and agglomeration have been assessed separately.

Estimates of the ozone concentration within each zone and agglomeration have been derived from the DETR’s automatic urban network (AUN) and rural networks. In particular, exceedence of the Long-term ozone objective for protection of human health (see Annex I, Table III of the Daughter Directive) was investigated in each zone and agglomeration according to the guidance presented in Article 9 of the Daughter Directive for ozone. Under the Directive, monitoring is mandatory in all zones and agglomerations where the measured 8-hour running mean ozone concentration exceeds 120 mg/m³. It was identified that this objective was exceeded in all agglomerations and zones within which monitoring has taken place between 1993 and 1999, with the exception of Glasgow and Coventry/Bedworth, which only commenced monitoring in 1997 and 1996 respectively. No monitoring data was available in seven agglomerations and four zones.

As a conservative estimate therefore, and taking into account the lack of data for Glasgow and zones and agglomerations where monitoring was not performed, it was assumed that ozone concentrations exceeded the long-term objective in all zones and agglomerations in the UK, as a result further investigation of the exceedence long-term objective for protection of vegetation was not performed. Monitoring is therefore required in all agglomerations and zones in the UK.

The number of additional monitoring sites required in each zone and agglomeration has been calculated using the guidance presented in Annex V Table I of the Daughter Directive. Calculations are based on the population of the individual zones and agglomerations, exceedence data for the Long-term objective for the protection of human health and the existing (June 1999) DETR rural network and AUN ozone monitoring locations.

It should be noted that the availability of other methods of assessment (empirical and chemical models) have been taken into account and this enables the number of sites required in each zone and agglomeration to be reduced, in accordance with Article 9 paragraph 5 of the Daughter Directive.

observations

Tables 1 and 2 present the number of additional sites required within agglomerations and zones throughout the UK. The minimum number of sites required assuming that fixed monitoring is the sole source of information (Minimum Site No. A), and the minimum number of sites required assuming that other means of assessment are available (Minimum Site No. B) are presented. The latter scenario is appropriate for the UK and additional site numbers required for compliance with the Daughter Directive have been calculated using these statistics. The existing number of ozone monitoring sites in the current DETR rural network and AUN are also presented. The additional siting requirements presented are based on the difference between the existing number of sites and the Minimum Site No. B statistic. These numbers assume the purchase of additional monitors, however, it should be noted that in some cases the short fall in existing monitors may be made up by the relocation of existing monitors which are currently located in areas that do not require monitoring under the Daughter Directive. Such cases are marked with an asterisk (*).

Assumptions have been made at this stage that the definition of station location (Urban, Suburban etc.) used within the Daughter Directive are directly comparable with those used in the UK. It should be noted however, that this may not be the case as such descriptions are not likely to be entirely categorical. Hence, it may be possible for monitoring locations described as urban in the UK to accommodate for a requirement to sample in a suburban area as defined by the Daughter Directive and visa versa. This observation may enable the number of additional monitoring sites required to be reduced, although no further investigation will be made within this assessment.

Table 1 Ozone monitoring requirements in UK agglomerations
1. England
		Minimum Site No. A		Minimum Site No. B		Existing Sites		Additional Sites
Agglomeration	Population	Urban	Suburban	Urban	Suburban	Urban	Suburban	Urban	Suburban
Greater London Urban Area	7650944	2	5	1	3	10	4	0	0
West Midlands Urban Area	2296180	2	3	1	2	4	0	0	2	*
Greater Manchester Urban Area	2277330	2	3	1	2	2	1	0	1	*
West Yorkshire Urban Area	1445981	1	2	1	1	2	0	0	1	*
Tyneside	885981	0	2	0	1	1	0	0	1	*
Liverpool Urban Area	837998	0	2	0	1	1	0	0	1	*
Sheffield Urban Area	633362	0	2	0	1	2	0	0	1	*
Nottingham Urban Area	613726	0	2	0	1	1	0	0	1	*
Bristol Urban Area	522784	0	2	0	1	1	0	0	1	*
Brighton/Worthing/Littlehampton	437592	0	1	0	1	0	0	0	1
Leicester Urban Area	416601	0	1	0	1	1	0	0	1	*
Portsmouth Urban Area	409341	0	1	0	1	0	0	0	1
Teesside Urban Area	369609	0	1	0	1	0	1	0	0
The Potteries	367976	0	1	0	1	1	0	0	1	*
Bournemouth Urban Area	358321	0	1	0	1	0	0	0	1
Reading/Wokingham Urban Area	335757	0	1	0	1	1	0	0	1	*
Coventry/Bedworth	331248	0	1	0	1	1	0	0	1	*
Kingston upon Hull	310636	0	1	0	1	1	0	0	1	*
Southampton Urban Area	276752	0	1	0	1	1	0	0	1	*
Birkenhead Urban Area	270207	0	1	0	1	0	0	0	1
Southend Urban Area	266749	0	1	0	1	0	0	0	1
Blackpool Urban Area	261355	0	1	0	1	0	0	0	1
Preston Urban Area	256411	0	1	0	1	0	0	0	1
Minimum site no. A assumes fixed monitoring as sole source of information
Minimum site no. B assumes that other sources of information are available and represents
a reduction in the Minimum site no. A value of one third (see Article 9, para 5)

* indicates that compliance with the Minimum site no. B requirement may be achieved by relocation of existing monitoring locations

(Table 1 continued)
2. Wales
		Minimum Site No. A		Minimum Site No. B		Existing Sites		Additional Sites
Agglomeration	Population	Urban	Suburban	Urban	Suburban	Urban	Suburban	Urban	Suburban
Swansea	272456	0	1	0	1	2	0	0	1	*
Cardiff	306904	0	1	0	1	1	0	0	1	*
3. Scotland
		Minimum Site No. A		Minimum Site No. B		Existing Sites		Additional Sites
Agglomeration	Population	Urban	Suburban	Urban	Suburban	Urban	Suburban	Urban	Suburban
Edinburgh Urban Area	416232	0	1	0	1	1	0	0	1	*
Glasgow Urban Area	1315544	0	2	0	1	1	0	0	1	*
4. Northern Ireland
		Minimum Site No. A		Minimum Site No. B		Existing Sites		Additional Sites
Agglomeration	Population	Urban	Suburban	Urban	Suburban	Urban	Suburban	Urban	Suburban
Belfast	475987	0	1	0	1	1	0	0	1	*
Minimum site no. A assumes fixed monitoring as sole source of information
Minimum site no. B assumes that other sources of information are available and represents
a reduction in the Minimum site no. A value of one third (see Article 9, para 5)

* indicates that compliance with the Minimum site no. B requirement may be achieved by relocation of existing monitoring locations

Table 2 Ozone monitoring requirements in UK zones
1. England
		Minimum Site No. A		Minimum Site No. B		Existing Sites		Additional Sites
Zone	Population	Suburban	Rural	Suburban	Rural	Suburban	Rural	Suburban	Rural
Greater London	7650944	na	na	na	na	na	na	na	na
North East	1287979	1	3	1	2	0	0	1	2
North West & Merseyside	2823559	1	7	1	5	1	0	0	5
Yorkshire & Humberside	2446545	1	5	1	3	0 (1)	1	1	2	*
East Midlands	2923045	1	7	1	5	1	0	0	5
West Midlands	2154783	1	5	1	3	0 (1)	1	1	2	*
Eastern	4788766	1	9	1	6	0 (2)	2	1	4	*
South East	3702634	1	7	1	5	0	3	1	2
South West	3728319	1	7	1	5	0 (1)	2	1	3	*
2. Wales
		Minimum Site No. A		Minimum Site No. B		Existing Sites		Additional Sites
Zone	Population	Suburban	Rural	Suburban	Rural	Suburban	Rural	Suburban	Rural
South Wales	1544120	1	4	1	3	0	1	1	2
North Wales	582488	1	2	1	1	0	0	1	1
Minimum site no. A assumes fixed monitoring as sole source of information
Minimum site no. B assumes that other sources of information are available and represents
a reduction in the Minimum site no. A value of one third (see Article 9, para 5)
Numbers in parentheses indicate existing urban monitoring locations in zones
* indicates that compliance with the Minimum site no. B requirement for suburban locations may be achieved by relocation of existing urban monitoring sites
(Table 2 continued)
3. Scotland
		Minimum Site No. A		Minimum Site No. B		Existing Sites		Additional Sites
Zone	Population	Suburban	Rural	Suburban	Rural	Suburban	Rural	Suburban	Rural
Scottish Borders	246659	0	1	0	1	0	1	0	0
Central Scotland	1628460	1	4	1	3	0	1	1	2
North East Scotland	933485	1	2	1	1	0	0	1	1
Highland	364639	1	1	1	1	0	1	1	0
4. Northern Ireland
		Minimum Site No. A		Minimum Site No. B		Existing Sites		Additional Sites
Zone	Population	Suburban	Rural	Suburban	Rural	Suburban	Rural	Suburban	Rural
Northern Ireland	1101868	1	3	1	2	0 (2)	1	1	1	*
Minimum site no. A assumes fixed monitoring as sole source of information
Minimum site no. B assumes that other sources of information are available and represents
a reduction in the Minimum site no. A value of one third (see Article 9, para 5)
Numbers in parentheses indicate existing urban monitoring locations in zones
* indicates that compliance with the Minimum site no. B requirement for suburban locations may be achieved by relocation of existing urban monitoring sites

Summary of additional monitoring requirements

On the basis of the assessments for zones and agglomerations presented in Tables 1 and 2 monitoring requirements have been estimated for England, Wales, Scotland and Northern Ireland. Total additional siting requirements for these regions of the UK are presented in Table 3 below. Where a range is given below, options are available for the relocation of existing monitoring sites to areas that require monitoring under the Daughter Directive.

Table 3 Summary of the total number of additional ozone monitoring sites required within the UK for compliance with the proposed Daughter Directive for Ozone

	England	Wales	Scotland	Northern Ireland
Agglomerations	7-22	0-2	0-2	0-1
Other Zones	27-31	5	6	0-2
Total	34-53	5-7	6-8	0-3

Hence from Table 3, the minimum number of additional monitoring sites required within the UK is 45, which assumes the relocation of 26 existing monitoring sites. If no relocation of existing monitoring is carried out the minimum number of additional monitoring sites required within the UK is 71.

Observations on monitoring requirements

On a purely scientific basis the number of additional monitoring sites required by the Daughter Directive would appear too excessive. Clearly, there is an additional monitoring requirement within agglomerations not well serviced by the existing networks to provide information to the public on possible health exposures. However, it is felt that the number of additional sites required in rural areas of zones is excessive when the spatial variation of rural ozone at sub-zonal level is expected to be small.

The following features of the Daughter Directive may be identified as leading to the requirement for large number of additional monitoring sites:

1. The use of the Long-term objective for protection of human health as trigger for mandatory monitoring in zones and agglomerations, as this objective is particularly stringent when applied to current concentrations.
2. Minimal relief, in terms of the reduction in required monitor provided by the availability of ‘other means of assessment’.
3. Monitoring requirements in rural areas are based on the total population the zone (urban + rural population) rather than just the rural population

estimated costs of additional ozone monitoring

A proportion of the additional ozone monitors required may be found from existing local authority sites and affiliated to the national network. As a worst case, however, we have assumed that none can be affiliated.

An automatic ozone analyser costs approximately £7,000. The Local Site Operator and maintenance contract would typically be around £10,000 per year. Running costs including management, QA/QC, data handling and electricity would be in the region of £2,000 per year. The estimated cost for each ozone-monitoring site would be in the region of £19,000 for the first year and £12,000 for subsequent years.

Based on the estimated numbers of additional sites summarised in Table 3, approximate costs have been calculated and are presented in Table 4 below. These figures assume that the monitors can be housed in an existing building and do not include the cost of sourcing electricity supply, (of particular implication at rural locations). A range of costs is provided in cases where monitoring requirements may be achieved by relocation of existing analysers. The lower figure reflects the cost of monitoring if all existing monitors currently located in areas that do not require monitoring under the Daughter Directive are relocated to areas that do require monitoring. The higher cost reflects the cost of additional monitoring if no relocation of existing monitors were to occur.

Table 4 Summary of the minimum additional monitoring requirements for ozone in the UK with cost data

	No. of new O3 sites	Cost in year 1	Cost in subsequent years
England	34-53	£646,000-1,007,000	£408,000-636,000
Wales	5-7	£95,000-133,000	£60,000-84,000
Scotland	6-8	£114,000-152,000	£72,000-96,000
Northern Ireland	0-3	£0-57,000	£0-36,000
Total	45-71	£855,000-1,349,000	£540,000-852,000

Appendix 2          Appendix 4