NOTES TO ACCOMPANY FORMS – GIBRALTAR PM10 TEN APPLICATION July 2010

Contents Introduction...... 2 Form 1...... 2 Annex to Form 1...... 2 Form 2...... 2 Annex to Form 2...... 3 Form 3a...... 4 Form 3b...... 5 Form 4a...... 6 Form 4b...... 6 Form 5a...... 7 Annex to Form 5a...... 7 Form 5b...... 7 Annex to Form 5b...... 8 Form 6...... 9 Form 7...... 11 Annex A to Form 7...... 11 Annex B to Form 7...... 11 Form 8...... 12 Annex to Form 8...... 13 Form 9...... 13 Form 10...... 13 Introduction

This document supports a formal time extension (TEN) application for PM10 (daily limit value) in Gibraltar by providing additional notes for clarification associated with the spreadsheet Forms (2008_2132_forms_en_Gib_v1.xls), in particular with references to the Air Quality Action Plan and other technical reports comprising the evidence base underpinning the application.

Form 1 a. - Reference year for this application is 2007 – the first year for which measured concentrations exceeded the LV AFTER correction for African dust (see notes for Form 2 below)

Annex to Form 1 i) REF_PM10_1 to REF_PM10_8 are reports commissioned specifically to support this TEN application and relate in their entirety to it. Relevant page numbers for each reference are given in appropriate parts of the Forms. REF_PM10_9 is the Environmental Statement associated with the new power station at Lathbury Barracks – the chapter on air quality and supporting appendices are referenced here.

Form 2 f, g, h. - Exceedence information values presented here are values calculated AFTER natural African dust component has been removed. There were 109 daily exceedences and an annual mean of 45 µg m-3 BEFORE correction for natural sources in 2007 (for 2007 methodology and results see REF_PM10_3. i. – Values presented here are values calculated AFTER natural African dust component has been removed. For 2006 methodology and results see REF_PM10_2. The 2005 measured PM10 data have also been corrected (using the methodology for 2006 and 2007) but this process has not been presented in a specific report because 2005 measured concentrations did not exceed either the annual mean of daily limit values as reported in Gibraltar’s 2005 Questionnaire.

Note that the concentrations reported to the Commission in the annual reporting Questionnaire for 2005, 2006 and 2007 were NOT corrected for African dust. For 2008, the necessary data from the Spanish authorities was provided to Gibraltar Environment Agency in time to undertake the correction and present the corrected numbers in the Questionnaire for this year. African dust corrected and uncorrected data for 2005 to 2008 monitoring data are summarised in Table below. Note that measured data for 2008 shows that there was an exceedence of the annual LV and the daily LV before correction for African dust and the daily LV was still (marginally) exceedence after correction for African dust. The natural correction exercise for 2008 has not been formally included in the PM10 TEN evidence base as it does not relate - - - - m m m m

g g g g µ µ µ µ ( ( ( (

n n directly to this application, however it is publicly accessiblen on the Gibraltar AQ n a a a 1 a e e e website . e m m m m

l l l l a a a a u u u u 2005 2006 2007 2008 n n n s s s n *

e e e n n n n s c c c e A A A A n n n ) ) ) ) c 3 3 3 e e e 3 n d d d e e e e d e e e e c c c e x x x c e e e

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l l l i i i y l a a a i D D D a D Uncorrected** 35.9 18 39.9 60 45.0 109 40.5 63 Corrected*** 31.1 3 35.4 29 39.2 72 35.4 36

* updated methodology in 2007 (REF_PM10_3) was used to updated 2006 PM10 data which further reduced the number of daily exceedences from 32 (the original corrected result for 2006) to 29. ** Uncorrected data was presented to the Commission via annual reporting Questionnaire for 2005- 2007. *** Corrected data was presented to the Commission via annual reporting Questionnaire for 2008

m. – estimate of roadside exceedence. Based on roadside classification of monitoring station where exceedence measured and localised influence of nearby unmade land contributing majority to measured concentrations. This estimate is graphically illustrated in the map related to Annex to Form 2 (shown in this documents below)

Annex to Form 2 Map presents the estimate of the exceedence measured at Rosia Road roadside monitoring site. This estimate in indicative and has been based on the proximity to the monitoring site and to the significant sources affecting it (i.e. unmade land and road traffic).

1 http://www.gibraltarairquality.gi/documents/Gib_natural_quantification_2008_v1.pdf Form 3a Units for values presented are µg m-3. The apportionment split for this Form has been based on the UNCORRECTED measured concentrations in 2007 (i.e. annual mean of 45 µg m-3) so that the quantified natural component (African dust) can be properly represented in the Form.

Despite the daily metric of LV exceeded, the values presented are contributions to annual mean concentrations derived from modelling studies that output this metric. This is a better indicator of the source split than trying to derive daily exceedence equivalents from these numbers. b. - The transboundary value is taken from the transboundary modelling study (REF_PM10_6, p.iii) and summarised in the source attribution study (REF _PM10_8, Table 16.1 on p.49) i.e. the addition of 5.4 µg m-3 primary and 2.8 µg m-3 secondary from anthropogenic transboundary sources. The natural value is taken from quantification of African dust analysis for 2007 (REF_PM10_3). The ‘other’ value is the concentration not accounted for by source apportionment studies summarised in REF_PM10_8, Table 16.1 on p.49 (i.e. annual mean for 2007 of 45 µg m-3 minus all the quantified components presented in this form). Evidence from Spanish research2 shows that marine aerosol (sea salt) is approximately 5 µg m-3 at the nearby La Linea site, approximately 2.3 km from the Rosia Road monitoring site. Using this as a representative indication of sea salt at Rosia Road, this would account for almost half the ‘other’ category at Rosia Road. If properly quantified at Rosia Road this would represent a significant reduction to measured PM concentrations, which - in addition to the contribution from African dust - would account completely for the natural component of PM10. d. – urban background values have been taken as contributions from power generation (at OESCO and MOD power stations) and shipping – values are taken from the respective technical reports (REF_PM10_5 for power stations and REF_PM10_7 for shipping) and are summarised in REF_PM10_8, Table 16.1 on p.49) e. – local sources were considered to be road traffic exhaust emissions and resuspended road dust (REF_PM10_8, Chapter 12.4.2) and contributions from wind blown dusts from local area of unmade land (REF_PM10_8, Chapter 13). Values were taken from summary table of these results (REF_PM10_8, Table 16.1 on p.49). f. – emissions inputs and model methodology has been described in detail in appropriate technical reports: REF_PM10_5 (power station contributions), REF_PM10_6 (transboundary contributions), REF_PM10_7 (shipping contribution) and REF_PM10_8 (Chapter 12 - road traffic contribution; Chapter 13 - contribution from unmade land).

Form 3b Form not completed – compliance was demonstrated for 2005 and 2006 (with quantification of natural African dust, see REF_PM10_2, and updated figures in REF_PM10_3, summarised in REF_PM10_8, Chapter 10) as demonstrated by the monitoring reported to the Commission via the annual reporting Questionnaire (see Table and notes for Form 2, sub i.). Because there was no evidence of exceedence prior to the reference year (2007), there was no need for additional measures to be implemented. When natural African dust quantification for 2007 demonstrated that exceedences remained even after adjustment for natural contributions, the implementation of a campaign for additional analysis to understand and characterise the PM10 problem was triggered – hence the evidence base supporting this application.

2 X. Querol, A. Alastuey, T. Moreno, et al. 2008. Spatial and temporal variations in airborne particulate matter (PM10 and PM2.5) across Spain 1999-2005, Atmospheric Environment, Volume 42, Issue 17, Fifth International Conference on Urban Air Quality, June 2008, Pages 3964-3979, ISSN 1352-2310, DOI: 10.1016/j.atmosenv.2006.10.071. Form 4a Form not completed – see notes for Form 3b noted above: no failure to comply by original deadline and no exceedence until 2007.

Form 4b b. - emission scenario used – see Form 3a, sub.f. – specific modelling reports explain emissions data used in each study. c. - For baseline assessment for 2011, it has been assumed that this is the same as the source apportionment from 2007 (reference year) i.e. the values used are the same as presented in Form 3a.

As in Form 3a, annual mean concentrations derived from modelling studies that output this metric are presented here. This is a better indicator of the source split than trying to derive daily exceedence equivalents from these numbers though annual mean concentrations have been related to exceedences of the daily LV by use of a relationship (REF_PM10_8, Chapter 5), following the example of the UK. This relationship provides reasonable representation within the annual mean concentration range (e.g. 20-40 µg m-3) but less so at small concentrations. Therefore it was decided to apportion sources according to annual mean metric rather than converting small numbers to number of daily exceedences. Baseline annual mean values for regional background, total background and at the location of exceedence have been taken directly from Form 3a sub b. d. and e. and are explained fully in notes for Form 3a sub b. above.

In addition to the annual mean representation of the source split, for indicative purposes only, an alternative representation of the daily LV exceedences for baseline conditions uses Spanish regional background measured data for regional background, measured data from Gibraltar Bleak House for the urban background and measured data from Gibraltar Rosia Road for the total background. These data are provided in the form, inclusive and exclusive of the effect of natural African dust.

The regional background values are derived from values presented in the table below for 2007. These regional background sites are used for the natural African dust quantification (REF_PM10_3, REF_PM10_4 and REF_PM10_5).

Daily exceedences of 50 µg m-3 Regional background African dust monitoring site All days days* removed Barcarrota 5 0 Sierra Norte 5 1 Alcoutim 0 0 Viznar 13 0 Nijar 6 0

Average regional background** 6 (5.8) 1 (0.2) * African dust days qualitatively determined by Spanish research (REF_PM10_3) ** No obvious regional background site for pairing with Gibraltar as all available are reasonably equidistant from Gibraltar. Therefore, all 5 available regional background sites are used in combination to provide an average that is deemed representative for Gibraltar – the number in brackets is the arithmetically calculated number, the number presented is a conservatively rounded number to provide a reasonable representation of the number of days.

The urban background value used was determined from numbers of daily exceedences from Bleak House with and without the correction for natural African dust. Note that there were no PM10 monitoring data at Bleak House for 2007 (the monitoring commenced here in 2008). The value presented for total background in the Form therefore is 2008 data (Gib_PM10_4) which is considered representative given that there are no significant source changes affecting this site from 2007 to 2008 and this value will be representative of urban background at the end of the extended deadline under a baseline scenario.

The total background value used was determined from numbers of daily exceedences from Rosia Road in 2007 with and without the correction for natural African dust (REF_PM10_3).

Form 5a No additional local measures implemented prior to LV coming into force. Measured concentrations indicated compliance until 2007 so only measures in place prior to this were air quality Directives and other transposed legislation.

Annex to Form 5a Not completed – see comment for Form 5a above.

Form 5b b. – These measures addressing unmade land (Gib_m1), road cleaning (Gib_m2), construction dust protocols (Gib_m5) and uncontrolled fires (Gib_m6) will all have been implemented prior to the end of the extension period. Additional measures, i.e. the new power station (Gib_m3) and Gibraltar Traffic Plan (Gib_m4) are much larger projects and require substantial time and resources to complete for planning and implementation and are not expected to be complete before the extended deadline. Nevertheless, the Gibraltar AQ Action Plan (REF_PM10_1) demonstrates a firm commitment to these additional measures beyond the extended deadline and these will result in further air quality improvements, increasing the headroom between the LV and anticipated measured concentrations. c. – see comments for sub b. above. Street cleaning (Gib_m2) has been implemented in late 2009, other measures due for completion before end of extended deadline are being implemented throughout 2010 and early 2011. Larger projects such as power station (Gib_m3) are expected to be complete by end 2013 and the Traffic Plan (Gib_m4) will be staggered in implementation of its various components between 2010 and 2012. e. – 2010 value includes Government funding for unmade land measure (Gib_m1), street cleaning measure (Gib_m2) and construction dust protocol measure (Gib_m5) (see REF_PM10_1). These funds have been allocated in the Action Plan (REF_PM10_1) in pounds sterling (GBP) and calculated in Euros for the form using an exchange rate of 1 GBP:1.2 EURO. f. – there are no anticipated additional costs borne by sectors affected; all costs are funded by Government of Gibraltar. Exchange rate used was 1 GBP:1.2 EURO. g. - values expressed as anticipated annual mean concentration (µg m-3) and number of days exceeding LV in 2011 – see justification for these values presented in table below. Annual mean concentration in 2011 based on baseline values for reference year (2007) and predicted changes from anthropogenic source resulting from measures to be implemented prior to extended deadline for compliance. Measures that have not been quantified (Gib_m4, Gib_m5, Gib_m6) or that have been quantified but will not be complete by the extended data for compliance (Gib_m3) have not been incorporated into this calculation – therefore, although the quantified measures included here demonstrate compliance at the end of the extended deadline, other measures are in place to ensure air quality benefits over and above that necessary to achieve compliance. Future analysis to characterise and quantify natural sea salt will be a further reduction to measured concentrations under the provision of the Directive to remove natural contributions. The expected number of daily exceedences (2.6, rounded to 3 for a meaningful number of daily exceedences) presented at the end of the extended deadline has been derived from the anticipated annual mean using the relationship presented in REF_PM10_8, Chapter 5.

Measured 2007 concentration 45 µg m-3 African dust removal -5.8 µg m-3 Capping/vegetating unmade land (Gib_m1) -10.9 µg m-3 Road cleaning (sweeping and flushing) (Gib_m2) -0.3 µg m-3 Estimated total annual mean concentration in 2011 with measures outlined in Gibraltar Air Quality 28.0 µg m-3 Plan

Percentage reduction from reference year (2007) 37.7% Estimated daily exceedences (calculated from annual mean as described in REF_PM10_8 3 (2.6) days Chapter 5) * * number in brackets is the arithmetically calculated number, the number presented is a conservatively rounded number to provide a reasonable representation of the number of days.

Annex to Form 5b b. and c. – not available. Specific emission controls not central to measures being implemented. d. - despite being daily exceedence metric, the impact of measures has been demonstrated as annual mean contributions (in µg m-3) from sources as they have been modelled. The relationship used to derive daily exceedences from annual mean concentrations is reasonable to use for total annual mean concentrations but is not appropriate at low concentrations therefore cannot be used to reasonably represent the number of daily exceedences related to individual measures/spatial scales.

No measures implemented affecting regional background contributions to PM10

No measures implemented affecting urban background contributions to PM10. The power station measure (resulting in an anticipated concentration reduction of 0.3 µg m-3) would be part of this category but has been omitted due to not being completed prior to the end of the extension period. Other measures that might contribute to this category have not been explicitly quantified and so have not been included.

Local air quality improvement resulting from measures has been calculated as 11.2 µg m-3 which is the combined benefit resulting from the unmade land measure (10.9 µg m-3; Gib_m1) and the street cleaning measure (0.3 µg m-3; Gib_m2). The quantification of the effect of street cleaning has been derived as 7% (0.3 µg m-3) of the 3.2 µg m-3 attributed to road dust resuspension (REF_PM10_8, Chapter 12.4.2 and summarised in Chapter 16 – Table 16.1 on p.49). This percentage reduction was taken from Querol et al. (2009)3 which found an effective decrease of 7-10% in measured concentrations resulting from road washing measures. Due to the uncertainty of the effect in Gibraltar, a conservative estimation has been made using the lowest end of this range – i.e. 7%. e. and f. – not relevant to this TEN application for PM10.

Form 6 Measures selected for implementation based on anticipated air quality benefit, feasibility of implementation and cost. Measures listed here are summarised – full details are provided in the Gibraltar AQ Action Plan (REF_PM10_1). b. - new power station (Gib_m3), see Gibraltar AQ Action Plan (REF_PM10_1) and Environmental Statement (REF_PM10_9) for specific details of this measure. c. - Gibraltar Traffic Plan (Gib_m4) – the bus fleet with be partially retrofitted with EURO 5 engines (upgraded from EURO 3 engines). d. – Gibraltar Traffic Plan (Gib_m4) - New vehicles coming into the fleet will be most up-to-date EURO standard engine. Government of Gibraltar fleet vehicles will be electric, hybrid or low emission vehicles. The new power station at Lathbury Barracks will use low sulphur marine diesel fuel. The desalination plant near Waterport area in the north of Gibraltar will replace oil fuel with electricity from the new power station. e. – specifically addressed by the Gibraltar Traffic Plan (Gib_m4) Low emission zone - City centre (predominantly pedestrianised already) will act as a low emission zone where electric goods vehicles only operate. Commercial deliveries

3 Fulvio Amato, Xavier Querol, Andres Alastuey, et al. Evaluating urban PM10 pollution benefit induced by street cleaning activities, Atmospheric Environment, Volume 43, Issue 29, September 2009, Pages 4472-4480, ISSN 1352-2310, DOI: 10.1016/j.atmosenv.2009.06.037. to be made to a freight mini-hub at Casemates Square and delivered to store by electric vehicle.

No differentiation of parking fees but parking will be closely monitored to ensure resident parking only where appropriate, enforced by police.

Speed limits in Gibraltar are closely monitored and enforced with CCTV cameras and police.

Slow modes of transport – walking and cycling encouraged by pedestrianised areas and take, ride and leave bike scheme.

Freight – see notes on LEZ and mini-freight hub above.

Improvement of public transport – all except one bus route will be made completely free of charge to use. The new park and ride facility near the frontier will facilitate bus transport into the centre and to other busy hotspots such as the beach. The new take, ride and leave bike scheme will encourage zero-emission transport around the locality.

Land use planning to ensure sustainable transport – see notes above on take, ride and leave bike scheme, park and ride facilities. There will also be a new dockyard road to improve north-south traffic flow. f. – encouragement to use bicycles (take, ride and leave bike scheme), buses (free on all except one route and new park and ride scheme) and to walk (pedestrianised centre and parking restrictions). g. - shipping emissions anticipated to drop resulting from Marpol Annex VI Regulation 14 (from 1 July 2010) which requires a mandatory switch to a lighter (cleaner) fuel type in close proximity to the shore (e.g. during bunkering operations in Gibraltar). The new power station at Lathbury Barracks will use low sulphur marine diesel fuel. The desalination plant near Waterport area in the north of Gibraltar will replace oil fuel with electricity from the new power station. h.- In July 2010, the Chief Minister announced measures related to the import duty on various vehicle types: zero import duty for pedal bikes, electric cars and electric motorcycles and 6% for hybrid cars to encourage uptake of these across the zone. To discourage the uptake of 2-stroke-engined scooters and motorcycles (these are known to be a significant contributor - approx. 50% - to PM10 from vehicle exhausts, see REF_PM10_8, Table 12.9 in Chapter 12.5) the import duty is to be raised from 6% to 30%.

No other additional measures in this category are being implemented as the dominant sources are being addressed via measures other than permitting and economic instruments. i. - Online public information website (http://www.gibraltarairquality.gi/) provides near real time measured concentrations across Gibraltar and provides information to enable behavioural change to reduce exposure of sensitive groups such as children or elderly people. No additional specific measures beyond this have been implemented.

Form 7 c. - brief description supplied here. Full description in accompanying Gibraltar Air Quality Plan (REF_PM10_1). d. - all measures coded "C" for National as Gibraltar is too small to make a distinction between local, regional and national administrative levels. All measures listed have been designed, approved and implemented by Government of Gibraltar with the assistance of the Gibraltar Environmental Agency. h. – Gib_m6 - coded measure as E (other) to reflect absence of single specific sector. i. - all measures coded 'Local' for spatial scale due to small area covered by Gibraltar.

Annex A to Form 7 Form not completed – compliance was demonstrated for 2005 and 2006 (with quantification of natural African dust, see REF_PM10_2, and updated figures in REF_PM10_3, summarised in REF_PM10_8, Chapter 10) as demonstrated by the monitoring reported to the Commission via the annual reporting Questionnaire. Because there was no evidence of exceedence prior to the reference year (2007), there was no need for additional measures to be implemented. When natural African dust quantification for 2007 demonstrated that exceedences remained even after adjustment for natural contributions, the implementation of a campaign for additional analysis to understand and characterise the PM10 problem was triggered – hence the evidence base supporting this application.

Annex B to Form 7 c. - Dates provided for implementation and completion are anticipated dates and may be altered in future according to the appropriate planning procedures and Government authorisation process. d. – specific emissions quantification has not been undertaken for this application. e. – This application covers PM10 only, hence this has not been completed. f. – Values presented are contributions to annual mean metric – seen notes for Annex to Form 5b sub.d (above).

Gib_m1 - Value presented is anticipated improvement associated with capping unmade land in close proximity to Rosia Road monitoring station and is derived from modelling described in REF_PM10_8, Chapter 13 and summarised in Table in REF_PM10_8, p. 49).

Gib_m2 - Value presented is anticipated improvement associated with street cleaning activities to reduce amount of lying road dust available for resuspension by passing vehicles. This value is derived from modelling described in REF_PM10_8, Chapter 13 and summarised in Table in REF_PM10_8, p. 49).

Gib_m3 - Value presented is anticipated improvement associated with replacing MOD and OESCO power stations with new power station further from built up areas. Values are based on modelling described in REF_PM10_5, and summarised in REF_PM10_8, Chapter 7 and in Table in REF_PM10_8, p. 49). Part of this measure is also the decommissioning of a third power station (Waterport power station) to the north of Gibraltar near to the airport. The impact of this power station has not been quantified with modelling but decommissioning it along with other existing power stations will have an additional, though unquantified air quality benefit that is not represented in the value presented here.

Measures Gib_m4, Gib_m5 and Gib_m6 are being implemented to go above and beyond the measures necessary to achieve compliance but have not been explicitly quantified and so numbers have not been presented here. It is envisaged that these will result in additional reductions in PM10 to increase the headroom between the LV and measured concentrations but reductions from these measures are not central to the demonstration of achieving compliance – compliance is anticipated as a result of measures Gib_m1 and Gib_m2 alone. Measure Gib_m3 (the new power station) will -3 result in a benefit of 0.3 µg m to annual mean PM10 urban background concentrations. However, this measure is unlikely to be complete by the end of the extended deadline in 2011 and so has been excluded from the values provided in Annex to Form 5b sub d. Measures Gib_m1 and Gib_m2 are anticipated to have a local impact as represented in sub f.

Form 8 b. – several of these Directives are not applicable to Gibraltar in its capacity as a UK Overseas Territory. Gibraltar is excluded from the Common Customs Territory and the Common Commercial Policy, therefore EU rules on the free movement of goods do not apply. e. – information presented here is directly taken from Form 8 of the UK TEN 4 application for PM10 .

Annex to Form 8

Please note comment made in Form 8b.

Form 9 b. – see notes for Form 3b. Date of first Plan or Programme – 2010 (Gibraltar Air Quality Action Plan, REF_PM10_1). No exceedences prior to reference year (2007)

4 http://www.defra.gov.uk/environment/quality/air/airquality/eu-int/eu-directives/airqual- directives/documents/annex-a-pm10-forms.xls therefore no plans or programmes or short-term action plans in place to reference prior to the 2010 Action Plan. c. - OESCO Power Station was permitted under the provisions of the Pollution Prevention and control Act 2001 which transposed Council Directive 96/61 into Gibraltar legislation.

Improvement condition 5 of the permit required the operator to carry out a detailed feasibility study into the erection of two 30-40 metre stacks to aid dispersion of emissions. Emission limit values were to be set once the stacks had been constructed. The feasibility study concluded that, because of engineering considerations the erection of these stacks was not possible. The Gibraltar Government has decided that this installation will be closed down within the next two years and replaced by a modern, cleaner power generating station. This installation has already been awarded a PPC permit and is at the pre-construction stage. PM10 monitoring carried out at the discharge stacks at OESCO power station show that, at 90% load, only one engine produced PM10 levels (54mg/Nm3) higher than the 50mg/Nm3 UK guideline for emissions from diesel engines (UK Environment Agency Sector Guidance note "IPPC Sector Guidance Note Combustion Activities"). There are no exceedences at 60% load. See REF_PM10_5 on the contribution from the power station to PM10 levels in Gibraltar. d. and e. – no installations in Gibraltar.

Form 10 While site-specific dispersion factors at the exceeding Rosia Road monitoring station do have an influence on the exceedences measured, they do not ‘cause’ the exceedence in their own right. Therefore, while some explanatory text describing this influence is summarised here, these factors have not been presented as an argument in this Form itself. b. c. d. and e. - Site specific dispersion factors and adverse climatic conditions at Rosia Road:  Lower wind speeds (REF_PM10_8, Chapter 4.2, p.11) measured at this monitoring site than at others in the Gibraltar AQ network and than the met data from the airport. This has been attributed to the sheltering influence of the topography of the Rock but does not result in significantly poor enough dispersion to cause the exceedence.  Wind direction restricted to direction of known anthropogenic (unmade land) and natural (sea salt) sources (REF_PM10_8, Chapter 4.2, p.11). Again related to the influence of the topography (the Rock) – wind directions measured at this monitoring station are predominantly westerly even when regional winds are from the east – there is a rotor effect where easterly winds overtop the Rock, ground in the Bay of Gibraltar and then loop back from the west towards Gibraltar. This results in sustained winds from the direction of the sea (sea salt) and unmade land (coarse particles).

f. and g.- Transboundary contributions: Modelling studies (REF_PM10_6, Chapter 4, p.17) have estimated a significant portion of PM10 in Gibraltar is from transboundary pollution as summarised in the table below. The majority of this is from sources in southern Spain and northern Morocco (REF_PM10_6, Chapter 3.5, p.15). This indicates that 21% of the PM10 concentration (after African dust correction) is from beyond the borders of Gibraltar and therefore outside of Gibraltar’s control. The table demonstrates that with African dust contributions and transboundary contributions removed, an annual mean concentration for 2007 would have been 31 µg m-3. Using the relationship presented in REF_PM10_8 (Chapter 5) and referenced in notes for Form 4b, sub c. (above), this annual mean concentration would be associated with approximately 6.6 (rounded to 7 for a meaningful number of days) days of exceedence. Therefore, without the significant transboundary component, compliance with the daily LV would be achieved.

Measured concentration (no African dust correction)* 45 µg m-3 Measured concentration (after African dust correction) 39.2 µg m-3 Primary transboundary contribution 2.8 µg m-3 Ssecondary transboundary contribution 5.4 µg m-3 Total transboundary contribution 8.2 µg m-3 Transboundary proportion of measured (corrected for 21% African dust) Measured concentration (after removal of African dust 31 µg m-3 and total transboundary contribution) Number of exceedence days estimated after removal of 7 (6.6) days African dust and total transboundary contribution * measured at Rosia Road in reference year (2007)