eh final progress report plus plots...6 f:\41740ike\progress report\report\eh final progress report...

$: EH final progress report plus plots...6 f:\41740ike\progress report\report\eh final progress report plus plots.doc Table 4 NO 2 Diffusion Tube Monitoring in East Hertfordshire Site$
East Hertfordshire Council AIR QUALITY PROGRESS REPORT Final Report August 2005

Job No: 41740IKE Reference: KW Date created: August 2005

Telephone: 0870 905 0906 Fax: 020 8663 6723 Website: http://www.fabermaunsell.com

Enterprise House 160 Croydon Road Beckenham Kent BR3 4DE

EAST HERTFORDSHIRE COUNCIL AIR QUALITY PROGRESS REPORT AUGUST 2005

Prepared by: ........................................ Approved by: ........................................ Dr Kirsten Wagner James Richer Environmental Scientist Technical Director 'The copyright in this document (including its electronic form) shall remain vested in Faber Maunsell Ltd ("FML") but the Client shall have a licence to copy and use the document for the purpose for which it was provided. FML shall not be liable for the use by any person of the document for any purpose other than that for which the same was provided by FML.'

1. Introduction.........................................................................................................................2 1.1. Progress Reports..................................................................................................................2 1.2. East Hertfordshire Council’s Previous Review and Assessment Reports............................2

2. Monitoring ...........................................................................................................................4 2.1. NO2 Monitoring Results ........................................................................................................4 2.2. PM10 Monitoring Results .......................................................................................................8

3. Dispersion Modelling Results .........................................................................................12 3.1. Introduction .........................................................................................................................12 3.2. Model Results .....................................................................................................................12 3.3. Model Verification and Errors .............................................................................................12

4. New Developments...........................................................................................................15

5. Conclusions ......................................................................................................................17

6. References ........................................................................................................................19 Appendix A UK National Standards and Objectives..................................................................20 Appendix B Monitoring Sites......................................................................................................23 Appendix C Model Results.........................................................................................................29 Table 1 NO2 Continuous Monitoring in East Hertfordshire..........................................................4 Table 2 Continuous Analyser Results, 2003 and 2004 ...............................................................4 Table 3 Calculation of Short-Term Monitoring Adjustment Factors ............................................5 Table 4 NO2 Diffusion Tube Monitoring in East Hertfordshire.....................................................6 Table 5 NO2 Diffusion Tube Results, 2003 and 2004 .................................................................7 Table 6 Calculation of Bias Correction Factors ...........................................................................7 Table 7 Continuous Analyser Results, 2003 and 2004 ...............................................................9 Table 8 Calculation of Short-Term Monitoring Adjustment Factors ............................................9 Table 9 Model Verification .........................................................................................................13 Table 10 UK Objectives set In Regulations..............................................................................21 Table 11 UK Air Quality Objectives not set in Regulations ......................................................22 Figure 1 Annual Mean NO2 Concentrations (2000 – 2004).......................................................8 Figure 2 Annual Mean PM10 Concentrations (2000 – 2004) ...................................................10 Figure 3 Location of Monitoring Site in Buntingford ................................................................24 Figure 4 Location of Monitoring Site near Buntingford ............................................................24 Figure 5 Locations of Monitoring Sites near Ware ..................................................................25 Figure 6 Locations of Monitoring Sites in Ware.......................................................................25 Figure 7 Locations of Monitoring Sites in Hertford ..................................................................26 Figure 8 Location of Monitoring Site in Stanstead Abbotts .....................................................26 Figure 9 Location of Monitoring Site in Little Hadham.............................................................27 Figure 10 Locations of Monitoring Sites in Bishop’s Stortford..................................................27 Figure 11 Locations of Monitoring Sites in Sawbridgeworth .....................................................28 Figure 12 Annual Mean NO2 Concentrations (�g/m3) and Monitor Locations, Bishop’s Stortford

(2004) 30 Figure 13 Annual Mean NO2 Concentrations (�g/m3), Bishop’s Stortford (2005) .....................31

TABLE OF CONTENTS

f:\41740ike\progress report\report\eh final progress report plus plots.doc

1 INTRODUCTION

2


1.1. Progress Reports Air quality Progress Reports form part of the local air quality management (LAQM) system introduced in the Environment Act 1995 and subsequent Regulations. The LAQM regime is designed to play a key role in the UK Government’s plans to achieve the air quality objectives outlined in the UK Air Quality Strategy [Ref 1] and subsequent addendum [Ref 2]. The present UK air quality standards and objectives are listed in Appendix A. The need for Progress Reports was identified as necessary in order to develop a longer-term vision for both LAQM and the review and assessment process. Presently, the requirement is for Progress Reports to be prepared annually, except in years when an Updating and Screening Assessment (and potentially a Detailed Assessment) is carried out. This report has been conducted in accordance with the guidance outlined in the Progress Report Guidance, LAQM.PRG(03) [Ref 3]. 1.2. East Hertfordshire Council’s Previous Review and Assessment Reports East Hertfordshire Council produced their Updating and Screening Assessment [Ref 4] in 2004. This assessment identified that exceedences of the objectives relating to nitrogen dioxide (NO2) were possible in Bishop’s Stortford and Ware. Following a short period of continuous monitoring at the two locations of concern, a Detailed Assessment [Ref 5] was produced in 2005. This assessment found that NO2 concentrations in Ware met the objectives, whereas exceedences were likely in Bishop’s Stortford. However, as a result of the preliminary nature of the monitoring data used in the assessment of Bishop’s Stortford, it was recommended that the data were re-assessed in this Progress Report once complete and ratified datasets were available. Thus, as well as fulfilling the requirements of the Progress Report Guidance, this report also re-examines NO2 pollution in Bishop’s Stortford in detail.

1. Introduction


2 MONITORING

4


2.1. NO2 Monitoring Results 2.1.1. Continuous Analyser Results There were four continuous analysers in East Hertfordshire that measured NO2 concentrations in 2003 and/or 2004, the locations of which are shown in the maps in Appendix B. Further details of the analysers and the data collected are presented in Tables 1 and 2.

Table 1 NO2 Continuous Monitoring in East Hertfordshire

Site Ref. Location Grid Ref. Site Type Distance to kerb/m

Distance of nearest

receptor to kerb/m

EH2 Edens Mount, Sawbridgeworth

548551, 215629

UB permanent N/A N/A

EH3 Cutforth Road, Sawbridgeworth

548250, 215400

RS permanent 1 6

EH4 Viaduct Road, Ware

536115, 214050

RS temporary 1 10

EH5 London Road, Bishop’s Stortford

549239, 221162

RS temporary 1 6

Notes: UB – urban background; RS – roadside; N/A – not applicable because site is urban background.

Table 2 Continuous Analyser Results, 2003 and 2004

Annual Mean NO2 Concentration /�g/m3

No. of Exceedences of the Hourly Mean Data Capture/% Site Ref.

2003 2004 2003 2004 2003 2004 EH2 23.4 21.5 0 0 98 98 EH3 36.0 31.1 0 0 99 94 EH4a N/A 28.4b N/A 0c (81.0)e N/A 98c EH5a N/A 41.9b N/A 0d (122.1)e N/A 98d

Notes: a – these datasets are only partially ratified, all other data are fully ratified; b – these annual mean concentrations have been calculated by adjusting short-term monitoring data; c – monitoring period 26/08/04 – 31/12/04; d – monitoring period 26/08/04 – 22/05/05, and e – equivalent to the 99.8th percentile of the dataset. It can be seen that there were no exceedences of the hourly mean NO2 objective at all four locations and that the annual mean objective was only exceeded at one site: EH5 in Bishop’s Stortford. This location is the subject of the dispersion modelling study discussed in section 3. The annual mean concentrations measured at sites EH2 and EH3 were lower in 2004 than those recorded in 2003, which is consistent with other measurements made nationwide (meteorological conditions in 2003 caused high pollution levels). The two permanent analysers are calibrated every fortnight by East Hertfordshire Council, are fully serviced by Horiba every six months and undergo independent QA/QC audits, conducted by NPL, every six months. The data are fully ratified by ERG. The temporary analysers were also calibrated every fortnight but were not independently audited. Servicing is conducted on a yearly basis; therefore EH5 is due to be serviced in August 2005. Consequently, ERG is only able to partially ratify the datasets. The two temporary analysers, EH4 and EH5, were installed in response to the recommendations of the Updating and Screening Assessment [Ref 4], which had identified the possibility of exceedences of the NO2 objectives at two locations in Ware and Bishop’s Stortford. The analyser in Ware was in operation from 26/08/04 to 31/12/04; it was removed when analysis of the data revealed that NO2 concentrations were well below the objectives. The analyser in Bishop’s Stortford was also commissioned on 26/08/04 but is still in operation because of the high levels of NO2 that were being measured. The data presented in Table 2 for EH5 are those collected up until 22/05/05. As both of the temporary analysers were only in

2. Monitoring

5


operation for parts of 2004, it was necessary to adjust the data in order to obtain annual mean concentrations. The methodology defined in Technical Guidance Note LAQM.TG(03) [Ref 6] was used to perform the adjustment. Data from four AURN background sites, namely Thurrock, Southend-on-Sea, London Brent and Northampton, were employed. The mean concentrations recorded at the four AURN sites during the monitoring periods of EH4 and EH5 were calculated and then compared with the annual mean concentrations for 2004 to derive adjustment factors. The average of these factors was then applied to the data collected at the temporary sites to determine annual mean values. Further details of these calculations are presented in Table 3.

Table 3 Calculation of Short-Term Monitoring Adjustment Factors

Mean NO2 Concentration/�g/m3

Site 01/01/04 to 31/12/04

26/08/04 to 31/12/04

26/08/04 to 22/05/05

Adjustment Factor (Ware)

Adjustment Factor

(Bishop’s Stortford)

Thurrock 29.5 33.9 42.1 0.868 0.699 Southend-on-

Sea 23.7 26.5 25.8 0.895 0.918

London Brent 35.5 39.1 35.3 0.908 1.006 Northampton 19.8 23.1 23.9 0.855 0.827

Average Factor 0.881 0.863 The resulting adjustment factors, 0.881 and 0.863, produce annual mean concentrations that are about 12% and 14% lower than the average concentrations recorded at the temporary sites. 2.1.2. NO2 Diffusion Tube Results The Council operate a network of diffusion tubes in East Hertfordshire, the locations of which are shown in the map in Appendix B. Further details of the diffusion tubes and the data collected in 2003 and 2004 are presented in Tables 4 and 5. It can be seen that there were exceedences of the annual mean NO2 objective at five sites in 2003: EHDC14 (London Road, Sawbridgeworth); EHDC17 (Dunmow Road, Bishop’s Stortford); EHDC18 (Stansted Road, Bishop’s Stortford); EHDC19 (London Road, Bishop’s Stortford), and EHDC22 (Viaduct Road, Ware). The annual mean concentrations measured in 2004 were lower than those in 2003 and there were no exceedences, although the concentration measured at EHDC19 (London Road, Bishop’s Stortford) is only just below the objective. Exceedences of the annual mean NO2 objective were also recorded in 2002 at sites EHDC17, EHDC19 and EHDC22 as reported in the Updating and Screening assessment. Consequently, continuous analysers EH4 and EH5 were installed and a Detailed Assessment[Ref 4] was conducted. This assessment concluded that although exceedences of the annual mean objective at Ware were unlikely, Bishop’s Stortford was of concern. NO2 pollution in this area is investigated further in section 3. The diffusion tubes were prepared and analysed by Lambeth Scientific Services. The tubes were prepared by coating the grids in a 50% v/v solution of the absorbent, triethanoamine (TEA), in acetone and analysed using colorimetry.

6


Table 4 NO2 Diffusion Tube Monitoring in East Hertfordshire

Site Ref. Location Grid Ref. Site

Type Distance to kerb/m

Distance of nearest receptor to

kerb/m EHDC1 Market Street, Hertford 532716, 212666 KS 1 1 EHDC3 Cedar Close, Hertford 531780, 212832 B N/A N/A EHDC4 Duncombe Road, Hertford 532298, 213613 B N/A N/A EHDC5 West Street, Ware 535743, 214355 RS 1 0 EHDC6 High Cross, Nr Ware 536663, 219500 KS 3 N/A EHDC7 Wood End, Nr Buntingford 532550, 225444 B N/A N/A

EHDC8 Bridge Street, Bishop’s Stortford 548833, 221396 KS 1 7

EHDC9 Warwick Road, Bishop’s Stortford 549608, 220934 B N/A N/A

EHDC10 West Road, Sawbridgeworth 548207, 215181 RS 2 0

EHDC11 High Street, Buntingford 536186, 229596 RS 1 3

EHDC12 Hockerill Street, Bishop’s Stortford 549154, 221242 KS 1 0

EHDC13 Edens Mount, Sawbridgeworth 548551, 215629 B N/A N/A

EHDC14 London Road, Sawbridgeworth 548066, 214716 KS 1 0

EHDC15 Spellbrook, Sawbridgeworth 548697, 217381 KS 1 N/A

EHDC16 London Road, Bishop’s Stortford (B1383) 549158, 220122 KS 1 6

EHDC17 Dunmow Road, Bishop’s Stortford (A1250) 549371, 221215 KS 1 4

EHDC18 Stansted Road, Bishop’s Stortford (B1383) 549301, 221314 KS 1 3

EHDC19 London Road, Bishop’s Stortford (B1383) 549247, 221193 KS 1 0

EHDC20 A120, Little Hadham 544287, 222634 KS 1 12 EHDC21 A10, Wadesmill, Ware 535918, 217547 RS 0 1

EHDC22 Viaduct Road, Ware (A1170) 536099, 214091 RS 2 0

EHDC23 High Street, Stansted Abbotts 538364, 211853 RS 1 0

EHDC24 Hertingfordbury Road, Hertford 531383, 212318 KS 1 N/A

EHDC25 Old Cross, Hertford 532451, 212677 KS 0 2

EHDC26 Parsonage Lane, Bishop’s Stortford 549513, 221961 RS 1 3

EHDC27 Pishiobury Drive, Sawbridgeworth 547357, 213743 KS 2 15

Notes: B – background; KS – kerbside; RS – roadside; N/A – not applicable because site is background or because there are no receptors located nearby.

7


Table 5 NO2 Diffusion Tube Results, 2003 and 2004

Annual Mean NO2 Concentration /�g/m3

Data Capture (No. of Months of Data) Site Ref.

2003 2004 2003 2004 EHDC1 33.4 28.5 12 12 EHDC3 23.6 19.3 12 12 EHDC4 22.4 19.8 12 12 EHDC5 31.6 20.7 12 10 EHDC6 32.2 22.8 12 12 EHDC7 18.8 17.1 12 12 EHDC8 31.4 22.7 12 12 EHDC9 20.8 17.1 12 12

EHDC10 31.9 23.6 12 11 EHDC11 24.2 17.1 12 12 EHDC12 31.3 30.3 12 12 EHDC13 24.1 21.2 11 11 EHDC14 42.1 33.0 12 12 EHDC15 35.2 26.1 12 11 EHDC16 36.1 27.6 11 12 EHDC17 51.4 37.4 12 12 EHDC18 45.7 34.7 11 12 EHDC19 53.0 39.0 12 12 EHDC20 28.8 25.2 12 12 EHDC21 34.7 26.0 12 12 EHDC22 45.2 35.2 12 12 EHDC23 35.7 29.1 12 12 EHDC24 38.8 24.3 12 12 EHDC25 38.0 30.3 12 12 EHDC26 35.2 26.6 11 12 EHDC27 36.5 22.3 12 12

Notes: the tube results have been corrected for bias; data in bold type indicates an exceedence of the annual mean NO2 objective. The diffusion tubes results presented in Table 5 were corrected for bias using adjustment factors, which were derived by comparing the NO2 concentrations measured by the continuous analyser at Edens Mount in Sawbridgeworth (EH2) and the co-located diffusion tube (EHDC13). The bias correction factors for 2003 and 2004 calculated by Faber Maunsell are presented in Table 6. The correction factor for 2002 calculated by netcen [Ref 3] is also included in the table.

Table 6 Calculation of Bias Correction Factors

Annual Mean NO2 Concentration /�g/m3 Year

EH2 (continuous analyser)

EHDC13 (co-located diffusion tube)

Bias Correction

Factor

2002 22.5 20.9 0.93 2003 24.1 23.4 1.03 2004 21.2 24.8 0.85

Note: EHDC13 results for May and August 2002, May 2003 and April 2004 were not available; therefore the corresponding periods of data have been removed from the data collected at EH2. Defra’s Appraisal Report of East Hertfordshire Council’s Detailed Assessment requested that the bias correction factor for 2004 be re-investigated and that consideration be given to the average factor listed on the Review and Assessment Helpdesk website. The locally derived factor of 0.85 has been selected for application to the diffusion tube results in preference to the average factor for the following reasons: • although the locally derived factor for 2004 differs to that calculated for 2003 (as pointed out

in the Appraisal Report), this difference is more acceptable when the factor for 2002 is taken into consideration

• there is a discrepancy between the factors listed on the Review and Assessment Helpdesk website for East Hertfordshire District Council for 2002 to 2004 and those calculated by

8


netcen and Faber Maunsell. Thus, the average factor for 2004 is partly based upon what appears to be an inaccurate factor for East Hertfordshire Council for 2004

• the application of the average factor for 2004 to the diffusion tube measurements for 2004 would result in annual mean NO2 concentrations that are generally greater (in some cases, much greater) than those derived for 2003. As has previously been stated, pollutant concentrations measured nationwide and at continuous analysers in East Hertfordshire were lower in 2004 than in 2003.

However, despite these points, it is conceded that the locally derived factor is not ideal as it is based upon the results of only one co-located tube. It is recommended that East Hertfordshire District Council co-locate three diffusion tubes with a continuous analyser. 2.1.3. Trends in NO2 Concentrations Annual mean NO2 concentrations measured over the last five years at several sites in East Hertfordshire are shown in Figure 1. Data from both continuous analyser and diffusion tube sites are included in the Figure and a variety of site types (roadside, kerbside and background) and locations throughout East Hertfordshire are also represented. It can be seen that there has been a general decline in annual mean NO2 concentrations, although concentrations measured in 2003 were generally higher than those measured in 2002 and 2004. These trends are also apparent in the data collected at the other monitoring sites in East Hertfordshire.

Figure 1 Annual Mean NO2 Concentrations (2000 – 2004)

0

10

20

30

40

50

60

2000 2001 2002 2003 2004

Year

Ann

ual M

ean

NO 2

Con

cent

ratio

ns/�

gm-3

EH01 Hertford KS

EH07 Nr Buntingford B

EH18 Bishop's Stortford KS

EH20 Little Hadham KS

EH22 Ware RS

EH23 Stanstead Abbotts RS

EH2 Sawbridgeworth UB

EH3 Sawbridgeworth RS

Note: B – background; KS – kerbside; RS – roadside. 2.2. PM10 Monitoring Results 2.2.1. Continuous Analyser Results PM10 is monitored using Tapered Element Oscillating Microbalances (TEOMs) at the two permanent sites in East Hertfordshire, EH2 and EH3. See section 2.1.1 for details of the locations and QA/QC procedures. The fully ratified results for 2003 and 2004 are presented in Table 7.

9


Table 7 Continuous Analyser Results, 2003 and 2004

Annual Mean PM10 Concentration /�g/m3

No. of Exceedences of the Daily Mean Data Capture Site Ref.

2003 2004 2003 2004 2003 2004 EH2 23.7a 17.8 14 (36.3)b 1 64 98 EH3 28.6 24.3 22 5 92 97

Notes: a – this annual mean concentration has been corrected because of the low data capture and b – equivalent to the 90th percentile of the dataset. It can be seen that there were no exceedences of the annual and daily mean PM10 objectives at both sites in 2003 and 2004. Levels of PM10 were greater in 2003 than in 2004, which is consistent with other measurements made nationwide. It should also be noted that as the data capture for site EH2 in 2003 was low, it was necessary to adjust the dataset in order to obtain the annual mean concentration. The adjustment was conducted as discussed in section 2.1.1. The mean concentrations recorded at the four AURN sites during the monitoring period of EH2 were calculated and then compared with the annual mean concentrations for 2003 to derive adjustment factors. The average of these factors was then applied to the data collected at EH2 to determine the annual mean value. Further details of these calculations are presented in Table 8.

Table 8 Calculation of Short-Term Monitoring Adjustment Factors

Mean NO2 Concentration/�g/m3 Site EH2 Monitoring

Period 2003 Adjustment

Factor

Thurrock 30.5 29.9 0.981 Southend-on-Sea 21.7 21.3 0.982

London Brent 26.9 26.3 0.978 Northampton 23.1 22.4 0.970

Average Factor 0.978 The resulting adjustment factor, 0.978, produces an annual mean concentration that is about 2% lower than the average concentrations recorded at EH2. 2.2.2. Trends in PM10 Concentrations Annual mean PM10 concentrations measured over the last five years at sites EH2 and EH3 are shown in Figure 2. It can be seen that between 2000 and 2003 there was a slight increase in annual mean PM10 concentrations. However, concentrations started to decrease in 2004.

10


Figure 2 Annual Mean PM10 Concentrations (2000 – 2004)

0

5

10

15

20

25

30

35

2000 2001 2002 2003 2004

Year

Ann

ual M

ean

PM

10 C

once

ntra

tions

/�gm

-3

EH2 Sawbridgeworth UB

EH3 Sawbridgeworth RS

11

3 DISPERSION MODELLING RESULTS

12

3.1. Introduction A dispersion modelling study of NO2 pollution in Bishop’s Stortford was conducted as part of East Hertfordshire Council’s previous Detailed Assessment [Ref 5]. This assessment found that exceedences of the NO2 annual mean objective were likely. However, as a result of the preliminary nature of the monitoring data used in the assessment, it was recommended that the model results were re-assessed in this Progress Report once complete and ratified datasets were available. The regional air quality model, AAQuIRE 6.1.1, was used in the Detailed Assessment [Ref 5] to predict the annual mean concentrations of NO2 in Bishop’s Stortford for the base year (2004) and the future air quality objective year (2005 for NO2). Further details of this model, the modelling procedure and the input data can be found in the Detailed Assessment [Ref 5]. 3.2. Model Results Figures 12 and 13 in Appendix C show the predicted annual mean NO2 concentrations for the base year (2004) and the objective year (2005), respectively. In the 2004 simulation, high concentrations of NO2 are predicted along all of the roads included in the study, with the junction being the area of greatest concern. Indeed, concentrations greater than 40 µg/m3 extend up to 36 m from the kerb of the junction. Sensitive locations are found along all of the roads included in the study. Pollutant levels for the objective year are generally predicted to be slightly lower than the levels in 2004. Such changes are mainly a consequence of reductions in the background concentrations of NO2 and greater vehicle emission controls. Increased pollution resulting from increases in traffic flows tend to be offset by these two factors. Despite the reduction, the predicted concentrations for 2005 still exceed the annual mean objective along all of the roads, with NO2 levels greater than 40 µg/m3 extending up to 32 m from the kerb of the junction. 3.3. Model Verification and Errors For an assessment such as this it is necessary that systematic and random errors, in both the modelling and the monitoring data, are considered and accounted for. The modelling results were verified by a consideration of the errors associated with the modelling process and the model input data. 3.3.1. Verification of Model Results The systematic errors in modelling results can arise from many factors, such as uncertainties in vehicle flows, speeds and the composition of the vehicle fleet. Such errors can be addressed and corrected for by making comparisons with monitoring data. The accuracy of the future year modelling results are relative to the accuracy of the base year results, therefore greater confidence can be placed in the future year concentrations if good agreement is found for the base year. The model results for the 2004 simulation were compared with 2004 monitoring data collected in the Bishop’s Stortford study area (see Table 9).

3. Dispersion Modelling Results

13

Table 9 Model Verification

2004 Annual Mean NO2 Concentration /�g/m3 Site Ref Site

Type Location Monitored Modelled

(uncorrected) Modelled

(corrected)

EH5 ca RS London Road, Bishop’s Stortford 41.9 28.8 41.9

EHDC12 dt KS Hockerill St, Bishop’s Stortford 30.3 28.0 40.0

EHDC18 dt KS Stansted Rd, Bishop’s Stortford 24.7 29.7 44.2

EHDC19 dt KS London Rd, Bishop’s Stortford 39.0 31.0 47.3

Notes: KS – kerbside; RS – roadside; ca – continuous analyser; dt – diffusion tube. The uncorrected model results do not agree particularly well with the monitoring results, with the exception of the data relating to diffusion tube site EHDC12. The greatest discrepancy between the results occurs at the continuous analyser location. The model results were corrected for the apparent systematic errors, in order to more accurately predict NO2 concentrations for the objective year. The first step in this process was to subtract the background concentrations of NOX from the modelled and monitored results to obtain the concentrations produced solely by traffic. Comparison of these figures allowed a linear scaling factor to be calculated, which was then applied to the modelled traffic contributions. Finally, the background concentration was added to the corrected modelled traffic contributions to produce the corrected modelled concentrations. It can be seen that following correction, agreement between the modelling and monitoring data for the continuous analyser site is much improved. However, the model over predicts concentrations at the diffusion tube locations. 3.3.2. Random Errors Random errors in modelling and monitoring data also contribute to discrepancies between the two datasets. It is possible to account for the degree of random error in dispersion model results according to guidance provided by the NSCA [Ref 10]. ‘Stock U Values’ allow the standard deviation of the model (SDM) to be calculated. The Stock U Value (U) for the NO2 annual mean objective is between 0.1 and 0.2. The SDM can be calculated according to: SDM = U x Co where Co is the air quality objective. Thus: SDM = 0.1 x 40 = 4 µg/m3. This calculation quantifies the uncertainty in the identification of areas where an exceedence of the air quality objective can be considered likely. For this reason, the plots presented in Appendix C have marked on them concentration contours at 36, 40 and 44 µg/m3. Taking the above SDM value into account, the area of exceedence in Bishop’s Stortford is extended along all of the roads in the study area to the 36 µg/m3 contour.


4 NEW DEVELOPMENTS

15


There are a number of new developments in East Hertfordshire that have the potential to have an impact upon local air quality. In particular, there are five sites at various stages of development all within 1.5 miles of the Detailed Assessment study area in Bishop’s Stortford where monitoring station EH5 is located. 1. Land at and adjacent to Jackson Square and riverside/Adderley Road, Bishop’s Stortford This redevelopment scheme involves a new food superstore and other retail units, food and drink outlets, residential properties and a two-storey car park. The local road network will also be affected as the Adderley Road will be closed and a new link road opened. 2. Land at the former John Dyde Training College, Anchor Street, Bishop’s Stortford This development involves 208 apartments, and surface and basement parking for 184 vehicles. 3. Atkins and Cripps Timber Yard, 95 – 97 London Road, Bishop’s Stortford An outline planning permission has recently been granted for 130 apartments, 2 commercial offices buildings and a car park. 4. Herts and Essex site, Haymeads Lane, Bishop’s Stortford Planning permission has been granted for 270 residential properties. 5. 90/96 South Street, Bishop’s Stortford Planning permission has been granted for 44 flats and 4 retail units. East Hertfordshire Council have also produced a site development brief for Goods Yard, Station Road, Bishop’s Stortford and are preparing a development plan for Mill site, Dane Street, Bishop’s Stortford. All of these new developments have the potential to impact upon local air quality. The Council are recommended to consider the introduction of additional NO2 diffusion tubes near the development sites to monitor the impacts.

4. New Developments


5 CONCLUSIONS

17


Faber Maunsell was commissioned by East Hertfordshire Council to produce an air quality review and assessment Progress Report in accordance with the guidance document LAQM.PRG(03) [Ref 3]. New monitoring results for 2003 and 2004 were presented, the dispersion modelling study of NO2 pollution in Bishop’s Stortford, conducted as part of the previous Detailed Assessment [Ref 5], was re-assessed and details of new developments that may affect air quality were provided. The following conclusions can be drawn. • There were exceedences of the annual mean NO2 objective at sites EHDC14 (London Road,

Sawbridgeworth), EHDC17 (Dunmow Road, Bishop’s Stortford), EHDC18 (Stansted Road, Bishop’s Stortford), EHDC19 (London Road, Bishop’s Stortford) and EHDC22 (Viaduct Road, Ware) in 2003, and at site EH5 (London Road, Bishop’s Stortford) in 2004.

• The re-assessment of the dispersion modelling results of NO2 pollution in Bishop’s Stortford demonstrated that the annual mean objective was predicted to be exceeded along all of the roads in the study area, with NO2 levels greater than 40 µg/m3 extending up to 32 m from the kerb of the junction investiagted.

• The Detailed Assessment demonstrated that exceedences of the NO2 objectives were not likely in Ware.

• Analysis of annual mean NO2 concentrations measured over the last five years revealed that there has been a general decline in NO2 pollution throughout East Hertfordshire, although there was a peak in concentrations in 2003.

• There were no exceedences of the annual and daily mean PM10 objectives at the two monitoring locations in Sawbridgeworth in 2003 and 2004.

• Analysis of annual mean PM10 concentrations measured over the last five years revealed that there was a slight increase in PM10 pollution between 2000 and 2003. However, concentrations started to decrease in 2004.

• Several large new developments were identified that had the potential to impact upon local air quality.

East Hertfordshire Council are recommended take the following actions: • Declare an Air Quality Management Area (AQMA) with regard to NO2 pollution in Bishop’s

Stortford. The AQMA boundary can follow either the 36 or 40 µg/m3 contour in the concentration plot of Bishop’s Stortford. Declaring with regard to the 36 µg/m3 contour would take into account the standard deviation of the model.

• Continue operating the continuous analyser at the temporary site in Bishop’s Stortford and improve the QA/QC procedures in place so that the monitoring data can be fully ratified.

• Co-locate three diffusion tubes, not just one, with the continuous analyser in Sawbridgeworth, as recommended by Technical Guidance Note LAQM.TG(03) [Ref 7].

5. Conclusions


6 REFERENCES

19


[1] Defra, The Air Quality Strategy for England, Scotland, Wales and Northern Ireland (2000), The Stationery Office

[2] Defra, The Air Quality Strategy for England, Scotland, Wales and Northern Ireland (2003),

The Stationery Office [3] Defra (2003) Local Air Quality Management. Progress Report Guidance.

LAQM.PRG(03). [4] East Hertfordshire Council, Updating and Screening Assessment, February 2004 [5] East Hertfordshire Council, Detailed Air Quality Modelling Study, February 2005 [6] Defra (2003) Local Air Quality Management. Technical Guidance. LAQM.TG(03). [6] NETCEN, National Air Quality Archive, http://www.airquality.co.uk/ [7] Air Quality Review and Assessment Website, www.uwe.ac.uk/aqm/review/index.html

6. References

20


Appendix A UK National Standards and Objectives

Table 10 UK Objectives set In Regulations

Objective EU Objectives Pollutant Applies

Concentration Measured as Compliance

Concentration Date All UK 16.25 µg/m3 (5 ppb) Running annual mean Dec 31, 2003 England & Wales 5 µg/m3 (1.5 ppb) Annual mean Dec 31, 2003 5 µg/m3 2010 Benzene Scotland 3.25 µg/m3 (1 ppb) Dec 31, 2010

1,3-Butadiene All UK 2.25 µg/m3 (1 ppb) Running annual mean Dec 31, 2010 n/a n/a

Carbon monoxide All UK 10 mg/m3 (8.6 ppm) Maximum daily running 8 hour mean Dec 31, 2003 10 mg/m3 2005

0.5 µg/m3 Annual mean Dec 31, 2004 0.5 µg/m3 2005 Lead All UK

0.25 µg/m3 Annual mean Dec 31, 2008

200 µg/m3 (105 ppb) 1 hour, 18 exceedences Dec 31, 2005 200 µg/m3 (18 exceedences) 2010

Nitrogen dioxide All UK 40 µg/m3 (21 ppb) Annual mean Dec 31, 2005 40 µg/m3 2010 50 µg/m3 24hr mean, 35 exceedences Dec 31, 2004 50 µg/m3 2005

All UK 40 µg/m3 Annual mean Dec 31, 2004 40 µg/m3 2005 50 µg/m3 24hr mean, 7 exceedences Dec 31, 2010 40 µg/m3 2010

Particles (PM10) (gravimetric)

Scotland 18 µg/m3 Annual mean Dec 31, 2010 20 µg/m3 2010

350 µg/m3 (132 ppb) 1 hour, 24 exceedences Dec 31, 2004 350 µg/m3 (24 exceedences) 2005

125 µg/m3 (47 ppb) 24 hour mean, 3 exceedences Dec 31, 2004 125 µg/m3 (18 exceedences) 2005 Sulphur dioxide All UK

266 µg/m3 (100 ppb) 15 min mean, 35 exceedences Dec 31, 2005 n/a n/a

Table 11 UK Air Quality Objectives not set in Regulations

Objective Pollutant Applies Concentration Measured as Compliance Notes

Polycyclic aromatic hydrocarbons (PAHs) All UK 0.25 ng/m3 Annual mean Dec 31, 2010 To be set in future regulations,

2005.

Ozone All UK 100 µg/m3 8 hour mean, 10 exceedences Dec 31, 2005 Ozone is a national rather then

local authority problem.

50 µg/m3 (provisional) 24 hour mean, 10 exceedences Dec 31, 2010

23 µg/m3 (provisional) Annual mean Dec 31, 2010 London

20 µg/m3 (provisional) Annual mean Dec 31, 2015

50 µg/m3 (provisional) 24 hour mean, 7 exceedences Dec 31, 2010

Particles (PM10) (gravimetric)

Rest of England & Wales

20 µg/m3 (provisional) Annual mean Dec 31, 2010

These particle objectives may be set in regulations once the EU has decided its new limit value.

Nitrogen oxides All UK 30 µg/m3 (16 ppb) Annual mean Dec 31, 2000 20 µg/m3 (8 ppb) Annual mean Dec 31, 2000

Sulphur dioxide All UK 20 µg/m3 (8 ppb) Winter mean

(October – March) Dec 31, 2000

Vegetative based directives kept out of regulations as national problem. Targets have been met.

23

Appendix B Monitoring Sites All the maps in Appendix B are reproduced from Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationary Office. © Crown Copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. East Hertfordshire Council LA100018528 Key

Reference Analyser

2 EH2/EHDC13 3 EH3 4 EH4 5 EH5 1 EHDC1 3 EHDC3 4 EHDC4 5 EHDC5 6 EHDC6 7 EHDC7 8 EHDC8 9 EHDC9 10 EHDC10 11 EHDC11 12 EHDC12 14 EHDC14 15 EHDC15 16 EHDC16 17 EHDC17 18 EHDC18 19 EHDC19 20 EHDC20 21 EHDC21 22 EHDC22 23 EHDC23 24 EHDC24 25 EHDC25 26 EHDC26 27 EHDC27

Map Scale 1:20000

535000 535500 536000 536500 537000228000

228500

229000

229500

230000

11

Figure 3 Location of Monitoring Site in Buntingford

532000 532500 533000225000

225500

226000

7

Figure 4 Location of Monitoring Site near Buntingford

535000 535500 536000 536500 537000217000

217500

218000

218500

219000

219500

220000

6

21

Figure 5 Locations of Monitoring Sites near Ware

Figure 6 Locations of Monitoring Sites in Ware

535500 536000 536500213500

214000

214500 5

22

4

531000 531500 532000 532500 533000212000

212500

213000

213500

214000

13

4

24

25

Figure 7 Locations of Monitoring Sites in Hertford

Figure 8 Location of Monitoring Site in Stanstead Abbotts

538000 538400

211600

211800

212000 23

544000 544500 545000222000

222500

223000

20

Figure 9 Location of Monitoring Site in Little Hadham

Figure 10 Locations of Monitoring Sites in Bishop's Stortford

549000 549500 550000

220000

220500

221000

221500

222000

222500

9

12

16

1819

26

517

547000 547500 548000 548500 549000213500

214000

214500

215000

215500

216000

216500

217000

217500

218000

10

14

15

27

2

3

Figure 11 Locations of Monitoring Sites in Sawbridgeworth

29

Appendix C Model Results

549100 549200 549300

220700

220800

220900

221000

221100

221200

221300

221400

20

24

28

32

36

40

44

48

52

56

This map is reproduced from Ordnance Survey material with the permissionof Ordnance Survey on behalf of the Controller of Her Majesty's StationaryOffice. © Crown Copyright. Unauthorised reproduction infringes Crowncopyright and may lead to prosecution or civil proceedings. East HertfordshireCouncil LA100018528

Scale: 1:5000 when A3 size

Figure 12 Annual Mean NO2 Concentrations (µg/m3) and Monitor Locations,

Bishop's Stortford (2004)

549100 549200 549300

220700

220800

220900

221000

221100

221200

221300

221400

20

24

28

32

36

40

44

48

52

56

This map is reproduced from Ordnance Survey material with the permissionof Ordnance Survey on behalf of the Controller of Her Majesty's StationaryOffice. © Crown Copyright. Unauthorised reproduction infringes Crowncopyright and may lead to prosecution or civil proceedings. East HertfordshireCouncil LA100018528

Figure 13 Annual Mean NO2 Concentrations (µg/m3), Bishop's Stortford (2005)

Scale: 1:5000 when A3 size

eh final progress report plus plots...6 f:\41740ike\progress report\report\eh final progress report...

Documents