The Highways Agency roadside air pollution monitoring network report …assets.highways.gov.uk/specialist-information/knowledg… · · 2013-04-30Transport Research Laboratory The

Transport Research Laboratory

The Highways Agency roadside air

pollution monitoring network report -

2010 Volume I

by J Pittman, D Gardiner and E Anderson

CPR1095 (I)

443 (1308) HALC

PROJECT REPORT

Transport Research Laboratory

PROJECT REPORT CPR1095 (I)

The Highways Agency roadside air pollution monitoring network report - 2010 Volume I

by J Pittman, D Gardiner and E Anderson

Prepared for: Project Record: 443 (1038) HALC

Impact of reduced emissions on air quality -

2010

Client: Highways Agency

(Andrew Bean)

Copyright Transport Research Laboratory March 2011

The views expressed are those of the author(s) and not necessarily those of Highways

Agency.

Name Date

Approved

Project

Manager Julia Pittman 03/05/2011

Technical

Referee David Gardiner 03/05/2011

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TRL CPR1095

Contents Amendment Record

This report has been issued and amended as follows

Version Date Description Editor Technical

Referee

1 18/01/11 Initial draft Trine Velling D Gardiner

2 22/03/11 Revised draft Julia Pittman /

Emma Anderson

D Gardiner

Final 29/03/2011 Revised draft including sponsors comments

Julia Pittman/ Dave Gardiner

D Gardiner

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TRL CPR1095

Executive summary

This report is the Tenth and final in a series summarising air pollutant concentrations,

meteorological data and traffic flows measured at sites across the Highways Agency long

term roadside monitoring network. The network comprises of four monitoring sites

located on the M4, M25 and M60 motorways and in the Bell Common Tunnel on the M25

motorway. The monitoring at Bell Common Tunnel site was affected by road widening

works which took place between 2008 and 2010. The ongoing roadwork’s restricted the

access to the monitoring site and as a result there were only two months of monitoring

data reported for Bell Common Tunnel. The data collected at Bell Common Tunnel is

included in this report but is not compared to the air quality objectives as a result of the

low data capture rate across the year. Concentrations of carbon monoxide (CO), oxides

of nitrogen (NOX), nitric oxide (NO), nitrogen dioxide (NO2) were measured at all sites.

In addition, concentrations of total hydrocarbons (methane (CH4) and non-methane

hydrocarbons (HC)), ammonia (NH3), particulate matter (PM10 and PM2.5) and ozone (O3)

were measured at the M4, M25 and M60 motorway sites and concentrations of sulphur

dioxide (SO2), hydrogen sulphide (H2S), aromatic hydrocarbons, polycyclic aromatic

hydrocarbons (PAH), aldehydes and metals were measured at the M25 and M60

motorway sites. Meteorological data (including wind speed, wind direction, temperature

and relative humidity) were collected at the M4, M25 and M60 motorway sites and solar

radiation was measured at the M25 site. Traffic flows were recorded at the M25, M4, &

M60 sites. No traffic data was available at the Bell Common site as a result of the

ongoing tunnel refurbishment work. The air pollution monitoring equipment used at each

site is comparable with equipment used in similar monitoring stations within the UK

National Air Quality Monitoring Network.

Table 0-1 provides a summary of statistics generated from data collected during 2010 at

each of the monitoring sites and compares this with objectives set out by the Air Quality

(England) Regulations 2000 (SI 2000 No. 928) and the Air Quality (England)

(Amendment) Regulations 2002 (SI 2002 No. 3043).

During 2010, the M25, M4 and M60 monitoring sites in the Highways Agency network

exceeded the NO2 annual mean objective concentration of 40 g/m3and the running 8-

hour mean objective for O3 was exceeded at the M4 and M60 site. Conversely, there

were no exceedances of the relevant objectives for SO2, PM10, PAH, benzene, CO or lead

at any of the monitoring sites during 2010.

Table 0-1: Annual summary of monitoring data recorded at sites in the

Highways Agency network, 01/01/2010 to 31/12/2010

Pollutant Objective Unit M25 M4 M60 Bell

Common

CO Max. daily running 8-hr

mean of 10 mg/m3 mg/m3 1.8 1.9 1.8 1.8

NO2

Max. of 18 exceedances of 1-hr mean of 200 g/m3

No. of exceedances

17 8 1 553

Annual mean of 40 g/m3 g/m3 61.6 47.9 49.7 187.3

O3 Max. of 10 exceedances of running 8-hr mean of 100

g/m3 g/m3 6 123 46 -

TEOM VCM adjusted

PM10

Max. of 35 exceedances of 24-hr mean of 50 µg/m3

No. of exceedances 11 3 0 -

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Pollutant Objective Unit M25 M4 M60 Bell

Common

Annual mean of 40 g/m3 40 g/m3 24.9 20.6 17.4 -

SO2

Max. 3 exceedances of 24-hr mean of 125 µg/m3

No. of exceedances

0 - 0 -

Max. 24 exceedances of 1- hr mean of 350 µg/m3

No. of exceedances

0 - 0 -

Max. 35 exceedances of 15-min mean of 266 µg/m3

No. of exceedances

0 - 0 -

In addition to this comparison with UK Air Quality Regulations, the monitoring data are

presented as average hourly data to enable direct comparison with the full time series

data measured at each site dating back to 1992 (i.e. the date of installation of the first

monitoring site on the M4 motorway).

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Contents

List of Tables iii

1 Introduction 4

2 Data collection 5

2.1 M4 (Theale 2), Pinglewood 5

2.2 M25, Bell Common Tunnel 6

2.3 M25 (M25B), Staines 6

2.4 M60, Kirkhams 8

2.5 Quality assurance and quality control 10 2.5.1 Site visits 10 2.5.2 Data checking 10 2.5.3 Data calibration and ratification 11 2.5.4 Data analysis 11

3 Compliance with UK Air Quality objectives and permitted exceedances 12

3.1 Nitrogen dioxide 12

3.2 Sulphur dioxide 16

3.3 Ozone 17

3.4 Particulate Matter 19 3.4.1 PM10 19 3.4.2 PM2.5 20

3.5 Aromatic hydrocarbons (BTEX) 21

3.6 Carbon monoxide 21

3.7 Lead 21

3.8 Pollutants not covered by the UK Air Quality Regulations 22 3.8.1 Polycyclic aromatic hydrocarbons 22 3.8.2 Aldehydes 23 3.8.3 Total hydrocarbons 23 3.8.4 Ammonia 24 *Monitoring period 7/09/2010 to 31/12/2010Error! Bookmark not defined. 3.8.5 Heavy metals 25 3.8.6 Hydrogen sulphide 26

3.9 Traffic data 26

4 Summary 28

References 29

Appendix A Figures and locations of monitoring sites 30

Appendix B Calibration and maintenance records 38

Appendix C Meteorological data 41

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Appendix D Air Quality Strategy objectives 42

Appendix E Conversion factors 43

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List of Tables

Table 0-1: Annual summary of monitoring data recorded at sites in the Highways Agency

network, 01/01/2010 to 31/12/2010 .................................................................. v

Table 2-1: Site information: M4 (Theale 2), Pinglewood ............................................. 5

Table 2-2: Site information: M25, Bell Common Tunnel .............................................. 6

Table 2-3: Site information: M25B, Staines .............................................................. 7

Table 2-4: Site information: M60, Kirkhams ............................................................. 9

Table 3-1: Compliance with UK Air Quality objectives, nitrogen dioxide (NO2) ............. 14

Table 3-2: Annual mean nitric oxide (NO) concentration .......................................... 14

Table 3-3: Annual mean total oxides of nitrogen (NOX) concentration ........................ 15

Table3-4: M25 NO2 diffusion tube results ............................................................... 16

Table3-5: M60 NO2 diffusion tube results ............................................................... 16

Table 3-6: Compliance with UK Air Quality objectives, sulphur dioxide (SO2) .............. 17

Table 3-7: Compliance with UK Air Quality objectives, ozone (O3) ............................. 19

Table 3-8: Compliance with UK Air Quality objectives, particulate matter (PM10) ......... 20

Table 3-9: Compliance with Provisional UK Air Quality objectives, particulate matter

(PM2.5) ......................................................................................................... 20

Table 3-10: Compliance with UK Air Quality objectives, benzene ............................... 21

Table 3-11: Compliance with UK Air Quality objectives, carbon monoxide (CO) ........... 21

Table 3-12: Compliance with UK Air Quality objectives, lead ..................................... 22

Table 3-13: Compliance with UK Air Quality provisional objective, benzo[a]pyrene

(B[a]P) ......................................................................................................... 23

Table 3-14: Annual mean concentration, acetaldehyde and formaldehyde .................. 23

Table 3-15: Annual mean concentration, methane (CH4) .......................................... 24

Table 3-16: Annual mean concentration, ammonia (NH3) Error! Bookmark not defined.

Table 3-17: Annual mean concentration, heavy metals ............................................ 26

Table 3-18: Annual mean concentration, hydrogen sulphide (H2S)............................. 26

Table 3-19: Annual average daily and hourly traffic flow .......................................... 27

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1 Introduction

TRL (Transport Research Laboratory) has operated an air pollution monitoring network

on behalf of the Highways Agency since the early 1990s, with the first site being

installed on the M4 motorway in August 1992. In 2010, there were 4 monitoring sites in

operation:

M4 (Theale 2), Pinglewood;

M25, Bell Common Tunnel;

M25 (M25B), Staines; and

M60, Kirkhams.

These sites were installed in August 1992, January 2007, June 1995 and May 1999

respectively.

This is the tenth, and final report in a series summarising air pollutant concentrations,

meteorological data and traffic flows measured at sites across the Highways Agency

network. Monitoring data collected at previous and current sites in the network and

reports previously published as part of this series are currently available on the TRL

website1, in the future they will be located on the Highways Agency website.

This report has been structured to provide a clear overview of data collected in 2010.

The report has been split into two volumes, this volume I contains:

Section 2: Data collection – this section provides details of the location of each

automatic monitoring site, the period the site has been in operation, the equipment

installed and the method used to collect data at each site.

Section 3: Compliance with UK Air Quality Objective Concentrations and Allowed

Exceedances – this section examines compliance with objectives at each monitoring site

in 2010. Pollutants not covered under the UK Air Quality Regulations are also discussed.

Section 4: Summary – this section provides a summary and draws conclusions from the

reported data.

Volume II of the report presents time series plots for pollutant concentrations recorded

at the four monitoring sites in 2010. It also contains a summary of historical data

including comparison with air quality standards and objectives, hourly data summary

statistics and traffic flows from when each site was installed until 2010.

1 http://www.trl.co.uk/research_development/sustainability/environmental_assessment_/air_quality/air_quality_archive.htm

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2 Data collection

2.1 M4 (Theale 2), Pinglewood

The first site installed as part of the Highways Agency network was located on the M4

motorway. This site (Theale 1) was installed in August 1992 and was situated at the

edge of the eastbound carriageway of the M4 motorway between junctions 11 and 12.

The Theale 1 site was operational until July 1994, after which the site was relocated to

make way for the construction of the M4 Reading motorway service area.

This second site, Theale 2, was installed in April 1995 and is located at the edge of the

hard shoulder on the eastbound carriageway of the M4 motorway approximately 2 km

east of the Theale 1 site. Monitoring equipment from the Theale 1 site was relocated to

the Theale 2 site and supplemented by two Rupprecht and Patashnick tapered element

oscillating microbalance particulate monitors (TEOM) (model 1400ab). One monitor

configured to measure particulate matter with an aerodynamic diameter of less than 10

microns (PM10), and the second monitor configured to measure particulate matter with

an aerodynamic diameter of less than 2.5 microns (PM2.5). Table 2-1 provides details of

the monitoring system and pollutants measured at the Theale 2 site. Photographs and a

map showing the location of the M4 site are provided in Appendix A.1.

Table 2-1: Site information: M4 (Theale 2), Pinglewood

Site M4, Theale 2, Pinglewood

Location Eastbound carriageway, between junction 11

and 12

Grid reference SU 69945 69435

Road type Rural motorway

Commencement date April 1995

Particulate inlet height above ground level 2.7 m

Particulate inlet height above enclosure roof 0.75 m

Particulate inlet distance from hard shoulder 4.1 m

Gaseous inlet height above ground level 1.5 m

Gaseous inlet distance from hard shoulder 0.5 m

Gaseous manifold flow rate 6.3 m/sec

Gaseous residence time 0.7 sec

Wind vane & anemometer height above ground level

4.25 m

Wind vane & anemometer height above enclosure roof

2.25 m

Relative humidity & temperature sensor height above ground level

2.0 m

Meteorological equipment distance from hard shoulder

6.0 m

Carbon monoxide (CO) Infra red (IR) absorption

Total oxides of nitrogen (NOX), nitrogen dioxide (NO2), nitric oxide (NO)

Chemiluminescence

Ozone (O3) Ultra violet (UV) absorption

Particulate matter (PM10 and PM2.5) Heated gravimetric - TEOM

Ammonia (NH3) Passive diffusion tubes

Meteorological conditions Wind speed, wind direction, temperature,

relative humidity

Traffic flow Automatic Traffic Counter (ATC)

During 2010, the M4 motorway site operated continuously with the following minor

disruptions to data collection:

Power failures to the site between 22/04/2010 to 23/04/2010, 22/05/2010 to

25/05/2010, 01/06/2010 to 02/06/2010, 13/06/2010 to 15/06/2010 and

21/06/2010 to 23/06/2010. Electrical disruptions during road maintenance work

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being carried out at M4 junction 12 to the east of the monitoring site. The HA

contractor responsible for this location was contacted as soon as the power

failures occurred and were requested to reinstate the power supply. The power

failures were thought to be as a result of the air conditioning units working at

maximum capacity during periods of hot weather causing the fuse to trip out. The

electrical equipment was replaced on the 23rd June.

Records of visits to the M4 monitoring site in 2010, including the reason for each visit

and actions performed during that visit are presented in Appendix B.1.

2.2 M25, Bell Common Tunnel

The monitoring site on the M25 motorway at the Bell Common Tunnel was installed in

January 2007. This site is situated on the eastbound (clockwise) carriageway of the M25

motorway to the west of junction 27. The site was installed with the aim of obtaining a

better understanding of the long term trend in emissions generated in the tunnel.

Monitoring at the Bell Common Tunnel site in 2010 was influenced by a major

construction and refurbishment project which resulted in closure of the eastbound tunnel

between November 2009 and March 2010. The monitoring equipment had to be

removed during this period to allow the contractor to use the stairwell where the

monitoring equipment was housed. Contractor changes during and after tunnel closure

caused chain of command and responsibility issues to arise for the construction

company. This in turn led to difficulties in gaining access to the stairwells and the

electricity supply. The tunnel closure and resulting issues resulted in the equipment

being reinstated on the 27th October 2010. Data collection was only carried out for two

months in 2010. The data has been included for information but was not compared with

objective concentrations due to the limited data capture.

Air quality data collected in the tunnel are unlikely to be as affected by meteorological

conditions as the other sites. However, prevailing wind directions, high wind speeds,

extreme ambient temperatures and changes in humidity may contribute to the dilution

or chemistry of the samples taken within the tunnel. Table 2-2 provides details of the

monitoring system and pollutants measured at the Bell Common Tunnel site.

Photographs and a map showing the location of the Bell Common Tunnel site are

provided in Appendix A.2.

Table 2-2: Site information: M25, Bell Common Tunnel

Site M25, Bell Common Tunnel

Location Clockwise direction, west of M25 Junction 27

Grid reference TL 544500, 201500

Road type Suburban motorway

Commencement date January 2007



Chemiluminescence


There were no issues with the equipment during this period. Records of visits to the Bell

Common Tunnel monitoring site, including the reason for each visit and actions

performed are presented in Appendix B.2.

2.3 M25 (M25B), Staines

In June 1995, a monitoring site (M25A) was installed on the M25 motorway between

junctions 13 and 14. Due to road widening, this site was closed in 2003 and relocated in

February 2004 (to site M25B) approximately 100m to the north of site M25A, and major

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road works on the M25 motorway during 2004 resulted in periods of data loss and

variations in vehicle emissions. The sample inlet was placed in its final position in

November 2005. Table 2-3 provides details of the monitoring system and pollutants

measured at the M25 site. Photographs and a map showing the location of the M25 site

are provided in Appendix A.3.

Table 2-3: Site information: M25B, Staines

Site M25B, Staines

Location Clockwise carriageway, between junction 13

and 14

Grid reference TQ 025725

Road type Rural motorway

Commencement date February 2004

PM10 inlet height above ground level 2.7 m

PM10 inlet height above enclosure roof 0.7 m

PM2.5 inlet height above ground level 2.4 m

PM2.5 inlet height above enclosure roof 0.4 m

Particulate inlet distance from hard shoulder 4.05 m

Gaseous inlet height above ground level 1.9 m

Gaseous inlet distance from hard shoulder 1 m

Gaseous manifold inlet gas flow rate 6.1m/sec


Wind vane and anemometer distance from hard

shoulder 5.05 m

Wind vane and anemometer height above ground level

3.75 m

Wind vane and anemometer height above enclosure roof

1.75 m

Temperature & relative humidity sensor height above ground level

2.1 m

Temperature & relative humidity sensor distance from hard shoulder

5.05 m

Pyranometer sensor height above ground level 3.45 m

Pyranometer sensor height above enclosure roof 1.45 m

Pyranometer sensor distance from hard

shoulder 4.5 m



Chemiluminescence


Total hydrocarbons (THC), methane (CH4), non-methane hydrocarbons (NMHC)

Flame ionisation detector (FID)

Sulphur dioxide (SO2), hydrogen sulphide (H2S) Ultra violet (UV) fluorescence

Particulate matter (PM10 and PM2.5) Heated gravimetric – TEOM


Nitrogen dioxide (NO2) Passive diffusion tubes (3 months)

Aromatic hydrocarbons – BTEX Pumped samples (gas chromatography)

Polycyclic aromatic hydrocarbons (PAH) Particle phase by Partisol (gas chromatography)

Aldehydes Pumped samples (high pressure liquid

chromatography)

Metals Particle phase – ICP


relative humidity, solar radiation

Traffic flows Automatic Traffic Counter (ATC)

During 2010, the M25 motorway site operated continuously with the following


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Power failures on 06/03/2010, 14/09/2010 and 01/10/2010. These were all minor

disruptions affecting data from all instruments. The power returned within a few

hours, there was no known reason for these power disruptions.

NOX instrument faults occurred on or between 11/04/2010 and 12/04/2010,

13/4/2010(8hrs), 14/04/2010(10hrs), 15/04/2010(8hrs), 16/04/2010 to

17/04/2010, 19/04/2010 (10hrs), 22/4/2010(10hrs), 23/04/2010 to 24/04/2010.

Continued faults resulted in the analyser being removed to the service company

on the 28th April for repair; no hot spare was available at this time. The analyser

was removed and repaired between 28/04/2010 and 13/05/2010. The service

report indicated the analyser had developed a fault on the photomultiplier tube

temperature control unit and was replaced.

The CO instrument was intermittently faulty from 15/02/2010 to 20/02/2010

where an onsite repair was thought to have resolved the fault. The repair was not

effective, and the instrument was removed on 20/02/2010 to external service

company for repair. No hot spare was available at this time. The analyser

required replacement parts ordered. The analyser was re-installed on

18/03/2010.

Ozone data is missing between 23/03/2010 to 24/03/2010 as a result of

instrument removal for routine service. The instrument was tested overnight. On

06/04/2010 the ozone lamp failed, and the instrument was removed to the

service company for repair and re-installed on 19/04/2010.

The SO2 analyser was serviced on the 23/03/2010 to 24/03/2010, no data is

available during this period. Invalid SO2 data was removed between the following

dates 16/4/2010 to 17/04/2010, 21/04/2010 to the 23/04/2010. The intermittent

failures of the analyser resulted in removal of the instrument on the 25/04/2010

and returned to the service company. The unit was re-installed on the to

27/04/2010.

The PM2.5 TEOM developed a flow fault on the 25/03/2010 and was removed for

repair. Replacement parts were required. The instrument was returned from the

service company and re-installed on the 07/04/2010. No data was available

during this period.

Horiba FID; TRL were advised by Horiba in 2009 that the Horiba 350 FID was no

longer service supported by Horiba and spares were no longer available. Other

service companies also advised they would not support the unit. It was agreed

with the HA to keep the analyser running as long as practicable. The analyser

developed an intermittent fault with the flame ignition unit. This resulted in either

the flame ignition unit being cleaned at site and relit or the unit being removed

for repair at the TRL workshop. 01/01/2010 to 12/01/2010 (period of heavy snow

and unable to access site), 11/02/2010 to 15/02/2010 (flame fault), 06/03/2010

to 11/03/2010 (removed to workshop), 28/04/2010 to 05/05/2010 (removed to

workshop), 15/06/2010 to 24/06/2010 (removed to workshop), 29/07/2010 to

30/07/2010 (flame fault), 09/09/010 to 10/09/2010 (flame fault), 22/12/2010 to

24/12/2010 (flame fault).


and actions performed are presented in Appendix B.3.

2.4 M60, Kirkhams

Monitoring began on the M60 motorway in May 1999. This site is located 18m from the

westbound hard shoulder (Manchester Orbital Road) on a shallow motorway

embankment approximately 300m north east of junction 17. Table 2-4 provides details

of the monitoring system and pollutants measured at the M60 site. Photographs and a

map showing the location of the M60 site are provided in Appendix A.4.

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Table 2-4: Site information: M60, Kirkhams

Site M60, Kirkhams

Location Eastbound carriageway, east of junction 17

Grid reference SD 81305 04995

Road type Suburban motorway

Commencement date May 1999

Enclosure level above road surface 2.0 m

Particulate inlet above ground level 3.2 m

Particulate inlet above enclosure roof level 0.6 m

Particulate inlet distance from hard shoulder 18 m

Gaseous inlet above ground level 3.5 m

Gaseous inlet above enclosure roof level 0.9 m

Gaseous inlet distance from hard shoulder 18 m

Gaseous manifold inlet flow rate 3.2 m/s


Meteorological equipment above ground level 6.8 m

Meteorological equipment above enclosure roof

level 4.2 m

Meteorological equipment distance from hard shoulder

18 m



Chemiluminescence


Particulate matter (PM10) Heated gravimetric – TEOM and Partisol

Total hydrocarbons (HC) and methane (CH4) Flame ionisation detector

Sulphur dioxide (SO2), hydrogen sulphide (H2S) Ultra violet (UV) fluorescence


Nitrogen dioxide (NO2) Passive diffusion tubes (3 months)

Aromatic hydrocarbons – BTEX Pumped samples (gas chromatography)

Polycyclic aromatic hydrocarbons (PAH) Particle phase by Partisol (gas chromatography)

Aldehydes Pumped samples (high pressure liquid

chromatography)


relative humidity


During 2010, the M60 motorway site operated continuously with the following


Short power failures of under 3 hours occurred on 21/01/2010 (1hr), 29/01/2010

(3hrs), 15/03/2010 (2hrs), 04/04/2010 (2/3hrs), 24/04/2010 (1hr), 26/04/2010

(1hr), 28/04/2010, 21/05/2010 (1hr), 08/06/2010, 17/07/2010, 25/07/2010,

09/08/2010 and 14/09/2010, there is no known reason for these power

disruptions. There were two longer power failures between 22/01/2010 to

23/01/2010 and 14/08/2010 to 15/08/2010, there is no known reason for these

disruptions. The power company investigated the fault and advised it had been

repaired.

There were logger disruptions between the following dates 16/09/2010 to

17/09/2010, 19/10/2010 to 20/10/2010 and 25/10/2010 to 12/11/2010. These

resulted in some minor disruption to data.

NOX instrument faults resulted in a loss of data between 15/03/2010 to

17/03/2010. The instrument developed a temperature fault on the 15/11/2010

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and was removed to the service company, no hot spare was available at this

time. The instrument was returned after repairs and re-commissioned on the

02/12/2010.

An SO2 analyser fault occurred between the 22/01/2010 and 23/01/2010. The

instrument was also removed for a service between 04/03/2010 and 08/03/2010

which resulted in some data loss. The instrument failed on the 29/03/2010 as a

result of lamp failure and was removed to the service company. The analyser was

reinstalled on the 08/04/2010.

A CO instrument fault occurred on the 19/10/2010 the instrument developed a

temperature fault and was removed for repair, it was reinstalled on the

21/10/2010. The instrument failed again on the 25/10/2010 and was removed to

the service company for repair to the PMT temperature control unit. The unit was

reinstalled on 12/11/2010.

An O3 instrument service was carried out on the 04/03/2010, which resulted in a

few hours data loss, and an O3 instrument fault occurred on 19/10/2010,

removed to workshop for repair and reinstalled on 21/10/2010. The instrument

had a catastrophic failure on 25/10/2010 and the instrument was removed to an

external service company. There was no hot spare available at this time.

The M60 cabinet was broken into and set on fire on the 20/12/2010 resulting in

extensive equipment damage, there was no data collected at the M60 from this date

until the end of December 2010.


and actions performed are presented in Appendix B.4.

2.5 Quality assurance and quality control

TRL quality assurance and quality control procedures require all data to be backed up on

a secure server and all documentation associated with each monitoring site to be

uniquely identified and securely stored. Quality assurance and quality control

procedures used by TRL follow those used in the Automatic Urban and Rural Network

(AURN)2 and are outlined below.

2.5.1 Site visits

TRL undertook regular site visits to calibrate the equipment at each monitoring site

during 2010, and the procedures used to carry out these calibrations follow those

outlined in the Site Operators Manual for the AURN3. Zero and span checking of the

equipment was completed on a fortnightly basis, and equipment was routinely serviced

by TRL and external contractors as required, in line with manufacturer’s

recommendations. Records of site visits to each monitoring site, including the reason for

each visit and actions performed at that site visit, are presented in Appendix B.

2.5.2 Data checking

TRL’s central data communication and logging facility (Enview 2000) has been externally

audited by the Environment Agency. This system was used to undertake daily data

inspections during office hours, during which three-day plots of data recorded at each

monitoring site were inspected for accurate date and time readings, continuous power

supply, continuity and validity of measurements, and maximum and minimum data

2 http://www.airquality.co.uk/reports/cat13/0910081142_AURN_QA_QC_Manual_Sep_09_FINAL.pdf 3 http://www.airquality.co.uk/reports/empire/lsoman/lsoman.html

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values. Any anomalies or queries arising from the daily inspections were brought to the

attention of the Project Manager, who initiated any necessary action (e.g. a site visit).

On a weekly basis, data collected by the management system was examined using

summary statistics and outlier analysis, and any unusual episodes were recorded and

examined over longer data periods. Unusual episodes were cross-referenced with peaks

and troughs recorded at other national monitoring sites, with any pollution episodes

recorded by the London Air Quality Network or sites in the DEFRA AURN where possible.

2.5.3 Data calibration and ratification

Air pollutant data was ratified as per AURN recommended procedures3. The calibration

and ratification process for automatic gas analysers corrects the raw dataset for ‘drift’ in

the zero baselines and the upper range of the instrument. The zero reading recorded

during the calibration exercise was used to adjust any offset of the baseline. The

difference between the span values obtained at two subsequent calibration visits was

used to calculate a linear scaling factor, which was applied to data collected between

these two visits. Following application of the scaling factor and adjustment of the

baseline, data was validated by visual inspection. Trends in the data were also

compared with other sites in the AURN.

2.5.4 Data analysis

Statistical analysis has also been carried out to allow for comparison with UK Air Quality

objective values set out by the Air Quality (England) Regulations 2000 (SI 2000 No. 928)

and the Air Quality (England) (Amendment) Regulations 2002 (SI 2002 No. 3043).

Compliance with the relevant objective has been assessed for each pollutant covered by

the Regulations (see section 3). A number of pollutants monitored at the sites within the

highways agency network are not covered by the UK Air Quality Regulations, and so the

concentrations of these pollutants have been compared with Environment Agency

guidelines. Although these pollutants are not covered by UK legislation, guidance values

for safe levels of human exposure exist and it is therefore considered constructive to

monitor these concentrations.

Statistical analysis of hourly data collected at each monitoring site has also been

undertaken. Minimum, maximum, mean and standard deviation values have been

calculated for each pollutant at each monitoring site for the year 2010. This allows for

comparison with data collected in previous years and the analysis of long term trends in

pollutant concentrations. Data for 2010 are presented together with historical datasets

in Volume II.

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TRL 12 RPN744 (I)

3 Compliance with UK Air Quality objectives and

permitted exceedances

This section compares data collected at the four Highways Agency monitoring sites in

2010, with UK Air Quality objective concentrations and permitted numbers of

exceedances. A summary of the UK Air Quality objectives and permitted numbers of

exceedances is provided in Appendix D. It is important to note that these objectives do

not apply at the monitoring sites in the Highways Agency network because the sites are

classified as areas not accessible to the public and therefore no relevant exposure exists.

It is, however, still considered useful to compare the monitored data with these criteria.

Each pollutant covered by the UK Air Quality Regulations is discussed in turn, and

percentage data capture rates for calibrated data are provided. Concentrations of non-

regulated pollutants are also presented and discussed in comparison with guidance

values recommended by the Environment Agency4.

3.1 Nitrogen dioxide

Nitrogen dioxide (NO2) concentrations are recorded by the continuous analysers as 15-

minute means. 1-hour means have been calculated from the 15-minute data to allow for

comparison with UK Air Quality objectives. Time-series plots of hourly NO2

concentrations for all sites are presented in Volume II of this report.

The UK Air Quality Regulations provide two objectives for NO2; the 1-hour mean

concentration of 200 µg/m3, which must not be exceeded more than 18 times per year,

and the annual mean limit of 40 µg/m3. A comparison with these objective

concentrations is shown in Table 3-1

The monitoring at Bell common was disrupted due to major tunnel refurbishment which

took place between 2008 and 2010. The stairwell area of the tunnel housing the

monitoring site was required by the contractors for storage. The monitoring equipment

was removed and was not re-installed until late October 2010. The re-installation of the

site was hampered by contractors having removed the mains electrics, and disposed of

the monitoring rack and high volume sample system. The power supply was reinstalled,

along with replacement rack and high volume system. This resulted in only two months

monitoring data being collected from Bell Common tunnel. Therefore the results are only

provided for information and are not compared to the air quality objectives.

Data capture rates (i.e. above 90%) for NO2 were achieved at the M4 and M25

monitoring sites in 2010. Disruptions to data collection caused by power failures (noted

in Section 2) at the M4 site were reported to the contractor carrying out the roadworks

as soon as they were noticed. The data capture rate for the M60 site was affected by a

number of incidents including, power disruptions as noted in Section 2, an instrument

fault which resulted in two weeks data loss, and vandalism to the cabinet on the

20/12/2010.

The data capture rate for Bell common tunnel reported in Table 3-1 is for the whole

year, and is therefore low, and not a true representation of data capture rates; for the

period the instruments were installed in the Bell common tunnel a data capture rate of

99.8% was achieved. Only two months of data were collected at the tunnel site in 2010

as a result of the refurbishment work. It was not possible to annualise the data from Bell

common tunnel as a minimum of three months data is required as set out in DEFRA’s

technical guidance TG-09.

During 2010, the annual mean NO2 objective value was exceeded at the M25, M4 and

M60 monitoring sites. With the high concentrations reported during the two month

monitoring period at Bell Common Tunnel it is likely that the annual mean objective

would be exceeded. The one hour mean objective was exceeded at all sites but was

4 http://www.environment-agency.gov.uk/business/topics/pollution/35761.aspx

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within the permitted number of exceedances under the UK Air quality regulations at the

M25, M60 and M4 sites.

The number of exceedances of the one hour mean objective at Bell Common Tunnel

during the two month monitoring period provided indicative results which were greater

than the number permitted under the Air Quality Objective.

The 1-hour mean NO2 levels at the M4 and the M60 site were observed to have slightly

lower concentrations than those recorded at the M25 site. It is suggested that this is

likely to be as a result of the increased volume of traffic at the M25 site compared with

volumes at the other two sites. The 1-hour mean concentrations at Bell Common Tunnel

were very high compared to the other sites. This is as a result of the tunnel environment

and reduced dispersion of pollutants. (Highways Agency, 2008, 2009)

The 1-hour mean NO2 concentrations at the M4 site were compared with concentrations

measured at Reading New Town monitoring site. Data from the Reading New town site

was available from the 13/03/2010 until the end of the year. The M4 and Reading New

town monitoring sites both followed similar trends. Exceedances at the M4 site occurred

on the 02/01/2010, 05/01/2010 and 13/01/2010. There was no data available for these

periods from Reading New Town. The 2/1/2011 occurred during the New Year Bank

Holiday weekend. There was an extensive programme of development work to the

bridges, roundabouts and slip roads at M4 J11 at this time. Lane closures and queuing

vehicles on the east bound carriageway prior to junction 11 had been observed on

several occasions and may have been one of the contributory factors to these

exceedences during a busy bank holiday period. January was host to a number of heavy

snow falls causing major disruption on the roads. Slow moving and stationary vehicles

during this period. The exceedance on the 05/01/2010 occurred during a period of heavy

snow, where an earlier accident had resulted in very long traffic delays. It is suggested

that this high concentration is real. The exceedance on the 13/01/2010 also occurred on

a day of heavy snowfall and slow moving traffic. It is suggested that this exceedance is

also real.

The 1-hour mean NO2 concentrations at the M25 site were compared with concentrations

measured at the London Hillingdon site located to the north of the M4 west of junction 4.

The data followed a similar trend for the majority of the year. There are short periods

when the concentrations at the two sites do not follow the same trend. These occurred

between 06/2/2010 and 12/02/2010, 06/03/2010 and 11/03/2010 and 14/06/2010 and

19/06/2010 and on the 14/01/2010, 26/01/2010, 09/02/2010, 08/03/2010,

17/04/2010, 18/04/2010 and 03/09/2010. During the periods in February and March the

concentrations at the M25 site were 50 µg/m3 to 120 µg/m3 higher than concentrations

recorded at the London Hillingdon site. These occasions coincided with winds from the

north suggesting that the lower NO2 concentrations at the Hillingdon site were as a result

of the northerly wind moving through the monitoring location towards the M4. The NO2

concentrations at the M25 site were more elevated as a result of the wind from the north

passing across the M25 towards the monitoring site. The NO2 concentrations in June

corresponded to low ozone concentrations. It is suggested that the higher NO2

concentrations at the M25 site would be as a result of a high rate of conversion of

vehicle NO emissions reacting with the ozone to form NO2 The exceedances at the M25

site also occurred during peak traffic times (07:00–09:00hrs and 16:00–19:00hrs) when

there would be increased vehicle volumes.

The M60 1-hour mean data was compared with data from local AURN air quality

monitoring sites, the urban background site located at Manchester Piccadilly, the urban

site located at Salford Eccles and the Bury motorway roadside side located on the north

side of the interchange at J17 of the M60. Data from all four sites indicated similar

trends. An exceedance of the 1-hour mean occurred at the M60 site on the 07/01/2010.

At this time a high concentration was also reported at the Manchester Piccadilly site,

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Bury Roadside site, and the Salford Eccles site at the same time as the M60 site. It is

suggested the increase NO2 concentration recorded at this time was as a result of

general pollution episode in the area. There was also a peak in NO2 concentrations on

the 06/12/2010 at the M60 site which also correlated with an exceedance at the Bury

Roadside site. This peak concentration was not observed at other monitoring sites in the

area and occurred during the peak travel time. It is suggested the increased

concentration may have be as a result of a localised traffic incident.

NO2 concentrations reported at Bell Common Tunnel were between 100-700µg/m3.

These high concentrations are consistent with previous years data reported at the site

and are a result of limited air dispersion and dilution conditions within tunnel

environments as described in a previous years monitoring report (Highways Agency,

2008). A large number of exceedances of 1-hour mean were observed, the majority of

which were at peak traffic flow times (07:00 – 09:00 and 16:00 – 19:00pm). During the

period 11/11/2010 to 20/11/2010 there were high concentrations recorded in the tunnel

throughout the day. It is uncertain why the concentrations did not drop during quieter

periods of the day. One possible explanation could be that the metrological conditions

outside the tunnel influenced the pollution dispersion within the tunnel. Strong easterly

winds penetrating the clockwise, eastbound bore, may have influenced the flow of air

through this bore encouraging concentrations to increase.

The annual one-hour mean values reported for the M4, M60 and M25 sites were

47.9ug/m3, 49.7ug/m3 and 61.6ug/m3 respectively.

Table 3-1: Compliance with UK Air Quality objectives, nitrogen dioxide (NO2)

Statistic Objective

concentration Permitted number

of exceedances M25 M4 M60

Bell Common

1 hour mean 200 g/m3 18 17 8 1 553

Annual mean ( g/m3)

40 g/m3 n/a 61.6 47.9 49.7 187.3*

Calibrated data capture (% of calendar year)

n/a n/a 93 94 83 18*

Bold type indicates exceedance of UK Air Quality objective * Bell Common Tunnel site in place between 27/10/2010 and 31/12/2010, the mean is calculated for this

period, no annualised mean was calculated (data capture 99.8% for the monitoring period)

For information, annual mean concentrations of NO and NOX recorded at each monitoring

site are provided in Table 3-2 and Table 3-3.

Table 3-2: Annual mean nitric oxide (NO) concentration

Statistic M25 M4 M60 Bell Common

Annual mean (µg/m3) 116.4 92.5 71.6 878.0

Calibrated data capture (% of calendar

year) 93 94 86 18*

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TRL 15 RPN744 (I)

Table 3-3: Annual mean total oxides of nitrogen (NOX) concentration

Statistic M25 M4 M60 Bell Common

Annual mean (µg/m3) 177.9 140.4 121.8 1065.3


93 94 86 18*

* Tunnel refurbishment resulted in only 2 months of data in 2010.

3.2 NO2 Diffusion tube results

During discussions with the Highways Agency in August 2010 it was agreed to deploy

NO2 diffusion tubes to support the oxides of nitrogen monitoring at the M25 and M60

sites. Two sets of triplicate NO2 diffusion tubes were deployed to monitor NO2

concentrations at the M25 and M60. A third set of triplicate tubes were deployed at the

sample inlet at the M60 site as this is located 18m from the roadside. The diffusion tube

monitoring began at the beginning of September and continues to March 2011. The bias

adjusted diffusion tube results for 2010 are provided in Table3-4 and Table3-5 with the

continuous analyser data for the same period for comparison.

The diffusion tube results at the M25 site are approximately 20 µg/m3 higher at the

roadside site than the background site. The concentration measured at the background

location would be expected to be lower with the increased distance from the traffic

source.

The diffusion tube results at the M60 site follow the expected trend with the

concentrations at the roadside location being the highest and the concentrations at the

background site, 18m from the M60 motorway traffic, being the lowest. The

concentrations observed at the inlet are approximately half those at the roadside. This is

to be expected as concentrations of NO2 generally drop off with increased distance from

the roadside source. The concentrations achieved by the diffusion tubes at the inlet site

compare well with the continuous analyser results across the same periods, this provides

confidence that the continuous analyser is responding well.

The NO2 concentrations recorded at the M25 background sites were higher at than at the

M60 site. Heathrow airport is located 5km to the north east of the M25 monitoring site.

It is suggested that increased NO2 background concentrations may be as a result of

additional contributions from the aircraft movements.

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Table3-4: M25 NO2 diffusion tube results

Date on

Date off

Period 1

02/09/2010

30/09/2010

Period 2

30/09/2010

4/11/2010

Period 3

04/11/2010

09/12/2010

Average

Distance from hard

shoulder (m)

Grid reference

(OS)

Sample tube

height

(m)

Roadside tube

average (µg/m3)

49.0 72.3 67.7 63.0 2m 502807,173568 1.9 m

Background tube

average (µg/m3)

33.6 52.2 53.9 46.6 50m 502745,173520 1.7m

Analyser average (µg/m3)

49.0 59.0 60.0 56.0 2m 502807,173568 1.9m

Table3-5: M60 NO2 diffusion tube results

Date on

Date off

Period 1

02/09/2010

30/09/2010

Period 2

30/09/2010

4/11/2010

Period 3

04/11/2010

09/12/2010

Average

Distance from hard

shoulder (m)

Grid reference

(OS)

Sample tube

height

(m)

Roadside

tube average (µg/m3)

91.8 106.2 85.9 94.6 1m 381294,405022 1.5m

Background tube

average (µg/m3)

33.9 38.1 43.0 38.3 39m 381309,404983 2.1m

Inlet tube average (µg/m3)

44.0 47.1 54.5 48.6 18m 381310,405004 3.5m

Analyser average (µg/m3)

45.7 43.9 56.7 48.7 18m 381310,405004 3.5m

3.3 Sulphur dioxide

Sulphur dioxide (SO2) concentrations have been recorded by the continuous analysers as

15-minute means at two of the four monitoring sites (the M25 and M60 motorways).

The UK Air Quality Regulations provide three objective concentrations for SO2 (measured

as 15-minute, 1-hour and 24-hour means). Table 3-6 shows that there were no

exceedances of the SO2 objective concentrations at either monitoring site in 2010. The

DEFRA air quality archive5 was checked for comparison and there were no exceedances

of any SO2 objectives at sites in close proximity to the M25 or M60 sites. A high data

capture rate for SO2 was achieved at the M25 site. The data capture rate at the M60 site

was slightly lower as a result of power failures and an instrument faults that occurred

between the 29/03/2010 and 08/04/2010. Further details of which are outlined in

Section 2.4.

The 15-minute, 1-hour mean and 24-hour mean concentration for SO2 at the M25 site

was less than 20ug/m3 and there were no significant peaks in the data.

5 http://uk-air.defra.gov.uk/data/exceedence

http://uk-air.defra.gov.uk/data/exceedence

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The 15-minute, 1-hour mean and 24 hour mean concentrations at the M60 data

indicated slightly higher concentrations than those recorded at the M25 site. The M60

data was compared with data from the urban monitoring sites located at Manchester

Piccadilly and Salford Eccles. Data from the sites followed similar trends. The SO2

concentrations recorded were less than 30ug/m3 for the majority of the monitoring

period. There were some small peaks in the data on 04/01/2010, 15/10/2010,

03/12/2010 and 06/12/2010 which were not reported at the Manchester Piccadilly site.

There was no data available from the Manchester Piccadilly site during the peaks on the

03/12/2010 and 06/12/2010. Two additional small peaks observed on 07/01/2010 and

22/06/2010 were recorded at Manchester Piccadilly site. It should be noted that these

maximum concentrations are well within the UK Air Quality objectives. There was one

large peak of 159ug/m3 on the 21/05/2010 which was not reported at the Manchester

Piccadilly or Salford Eccles sites. The concentration started to increase at 03:45hrs and

remained high until 08:00hrs in the morning. The data recorded at the Manchester

Piccadilly site increases slightly over the same time period, suggesting that there might

have been a pollution episode at this time that may have been closer to the M60 site.

Further investigations found that high SO2 concentrations were reported an hour later at

Liverpool Speck site, it is possible a pollution incident occurred near the M60 site and

was carried by winds to the north-west winds to the Liverpool Speck site. The peak is

believed to be real, the cause of the higher concentration is unknown.

The 1-hour mean Time-series plots of 15-minute, 1-hour and 24-hour mean SO2

concentrations recorded at the M25 and M60 sites are presented in Volume II of this

report.

Table 3-6: Compliance with UK Air Quality objectives, sulphur dioxide (SO2)

Statistic Objective


of exceedances M25 M60

15-minute mean

266 µg/m3 35 0 0

1-hour mean 350 µg/m3 24 0 0

24-hour mean 125 µg/m3 3 0 0

Calibrated 1-

hour data capture (% of calendar year)

n/a n/a 97 85

3.4 Ozone

Ozone (O3) concentrations have been recorded by the continuous analysers as 15-

minute means. 1-hour means have been calculated from the 15-minute data and the

running 8-hour mean has been calculated for comparison with the UK Air Quality

objective at the M4, M25 and M60 monitoring sites.

O3 is a secondary pollutant (i.e. it is not emitted directly from any source e.g. road

traffic). O3 forms in the lower atmosphere by reactions between volatile organic

compounds (VOCs), CO and NOX in the presence of sunlight. O3 reacts with NO emitted

directly from vehicle exhausts to form secondary NO2. At a roadside location, there is

routinely an excess of NO and thus the limit to the formation of NO2 is usually

determined by the availability of O3. During the summer months, higher concentrations

of O3 are typically observed as a result of increasing sunlight.

Concentrations of NO2 and O3 measured at the Highways Agency roadside sites have

been analysed in conjunction with each other in order to explain episodes of high and

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low concentrations of these pollutants. Time-series plots presented in Volume II of this

report have been annotated accordingly. Table 3-8 shows exceedances of the 8-hour

running mean at the M25, M4 and M60 monitoring sites. The reported exceedances of

the 8-hour running mean at the M60 and M4 site exceed the number permitted under

the air quality objectives.

High data capture rates for O3 were achieved at the M25 and M4 sites in 2010. The data

capture rate at the M60 site is slightly lower due to minor power failures and an

instrument fault which occurred on the 25/10/2010 and was not re-installed prior to the

end of the year as discussed in Section 2.4.

The data reported at the M25 site has been compared with three local AURN sites,

London Teddington, Reading New Town and London Hillingdon. The exceedances

reported at the M25 site are all in the summer months when higher levels of ozone

would be expected. The exceedance at M25 on 24/05/2010 was also reported at London

Hillingdon, Reading New town, and London Teddington sites and each site indicated very

low concentrations of NO2. Exceedances on the 23/06/2010 and 27/06/2010 were also

experienced at London Teddington site with high levels at Reading New Town and

London Hillingdon. The exceedance at the M25 site in August was not experienced at any

of the other local sites but high levels were observed at Reading New Town. It is

suggested that the increase in O3 concentrations during this period may be as a result of

localised weather conditions combined with a large volume of traffic during the peak

holiday period.

The M60 ozone concentrations were compared to those reported at other local AURN

sites including, Wigan centre and Salford Eccles. There were a number of exceedances of

Ozone at M60 site in January which correspond to very low levels of NO2 at the site.

These exceedances were not reported at any other local site but a similar trend with

lower concentrations was observed at the Salford Eccles site. During this time there was

heavy snow across the region which may have influenced traffic flow on the M60 and

therefore influenced the ozone levels recorded. It is likely that the cold calm conditions

at the M60 site trapped the ozone resulting in periods of high ozone at the M60. The

exceedance in April (24/04/2010) was also reported at Glazebury and Liverpool Speck at

the same time and suggests that this was promoted by a regional weather episode.

There were also high levels at all other local sites. During the periods of exceedances in

June and September at the M60 site high concentrations were reported at all local sites.

There were several exceedances of the 8-hour running mean at the M4 site. The

majority of these exceedances occur in the summer months of May, June and July. This

is a period when the majority of high concentrations of ozone are likely to occur. The M4

ozone concentrations were compared with those reported at local AURN sites at Harwell

and Reading New Town. All three sites follow a similar trend with exceedances reported

at Harwell and Reading New Town during the same periods. This suggests that the high

concentrations are not only due to local traffic conditions, but may be as a result of a

regional pollution episode. The exceedances on 12/10/2010 and 12/11/2010 at the M4

site were not reported at Harwell and Reading New Town. It is suggested that this was

as a result of a localised pollution episode indicated by other species monitored at this

site during these periods.

It was agreed with the HA to discontinue monitoring ozone in Bell Common Tunnel for

2010 as concentrations were consistently very low, and as a result of the tunnel

refurbishment disruption. Therefore no data for Bell Common Tunnel are shown in Table

3-7.

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Table 3-8: Compliance with UK Air Quality objectives, ozone (O3)

Statistic Objective

concentration

Permitted number of

exceedances M25 M4 M60

8-hour running mean

100 µg/m3 10 6 123 46


n/a n/a 96 95 80

Bold type indicates exceedance of UK Air Quality objective

3.5 Particulate Matter

Particulate matter concentrations for PM10 and PM2.5 are recorded as 15-minute means at

each monitoring site. 1-hour and 24-hour means have been calculated from the 15-

minute data to allow for comparison with the UK Air Quality objectives for PM10 and the

proposed objectives for PM2.5, which are due to come into effect in 2020.

High data capture rates (i.e. above 90%) for PM10 and PM2.5 were achieved at the M25

and M4 motorway sites. The data capture rate at the M60 site was slightly lower due to

a number of issues including power failures and logger faults as discussed in Section 2.4.

This report does not contain particulate data collected at the Bell Common Tunnel site in

2010, as the Osiris monitor was removed in July 2008 due to a lack of space in the

tunnel caused by the major construction and refurbishment programme.

3.5.1 PM10

As discussed in previous monitoring reports (Highways Agency, 2008 & 2009), prior to

processing and ratification, the raw PM10 concentrations have been adjusted to a

gravimetric equivalent using the Volatile Correction Model (VCM) as recommended

by Defra (2009). This adjusts the TEOM data using the "purge" concentration

measured by an FDMS analyser, assuming this represents the volatile component that

has been lost. A "VCM web portal" has been established that allows this correction to be

derived from the mean of up to three nearby FDMS analysers in the national network,

along with meteorological measurements. Data presented in Table 3-10 have been

corrected using this method. For consistency with previous reports, the PM10 data

collected by TEOM analysers have also been adjusted by *1.3 and these statistics are

presented in Volume II (Section 6) of this report. As also observed with the 2008 and

2009 data, the PM10 annual means obtained using the VCM method are lower than those

obtained using TEOM *1.3 correction method.

Refurbishment work at Bell Common Tunnel resulted in the particulate monitor

previously located in the tunnel being removed. It was not possible to co-locate the

analyser within the confines of the refurbished tunnel. No comparisons are reported in Table 3-9.

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Table 3-10: Compliance with UK Air Quality objectives, particulate matter

(PM10)

Statistic Objective

concentration

Permitted number of

exceedances

Measurement method

M25 M4 M60

24-hour mean 50 µg/m3 35 TEOM adjusted

(VCM) 11 3 0

Annual mean (µg/m3)

40 µg/m3 n/a TEOM adjusted

(VCM) 24.9 20.6 17.4

Calibrated data capture

(% of calendar year)

n/a n/a - 99 94 71

Table 3-10 shows that the annual mean PM10 objective was not exceeded at any of the

motorway monitoring sites during 2010, and that despite there being exceedences of the

24-hour mean objective for PM10 at the M25 and M4 sites, the number of exceedances

was below the 35 permitted per year under the objective.

Time-series plots of the 24-hour mean concentration of PM10 are presented in Volume II

of this report. The 24-hour mean concentration of PM10 was typically between 10 and

40µg/m3 at all three sites. Exceedances of the 24-hour mean objective occurred at the

M4 site in January, February and March and at the M25 site in January, February, April,

October and December. The exceedances in January (25th to 27th), February (18th) and

October (8th) all occurred at times when the London Air Quality Network reported a

pollution episode for PM10. The pollution episodes were due to light easterly winds

bringing secondary PM10 from continental Europe with the cold calm conditions leading to

poor dispersion. These episodes are the likely cause of the exceedances at the M4 and

M25 sites these periods.

The 24-hour mean PM10 concentrations reported at the M60 site were compared with the

local AURN sites; Bury roadside, Warrington and Salford Eccles. All of the sites followed

the same trend to the M60 site with all sites reporting similar concentrations. There

were no exceedances of the 24-hour mean at the M60 site in 2010.

3.5.2 PM2.5

Table 3-11 shows that there were no exceedances of the provisional UK Air Quality

objective concentration for annual mean PM2.5 at any of the monitoring sites in 2010.

High data capture rates (i.e. above 90%) for PM2.5 were achieved at the M25, M4 and

M60 motorway sites.

Table 3-11: Compliance with Provisional UK Air Quality objectives, particulate

matter (PM2.5)

Statistic Objective

concentration

Permitted number of

exceedances

Measurement method

M25 M4 M60

Annual mean 25 g/m3 n/a TEOM 14.3 10.9 14.8

1-hour mean Calibrated

data capture (% of

calendar year)

n/a n/a - 94 93

93

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3.6 Aromatic hydrocarbons (BTEX)

Aromatic hydrocarbons, including benzene, toluene, ethyl benzene, meta-, para- and

ortho-xylene (collectively known as BTEX), are measured at the M25 and M60 sites using

pumped passive diffusion tubes that provide daily mean concentrations for each

pollutant. Table 3-12 shows that the UK Air Quality objective value for benzene (annual

mean of 5 g/m3 in England and Wales) was achieved at both the M25 site and the M60

sites in 2010. The monitoring of BTEX at the M60 site was discontinued as the results

had been consistently low for a number of years. The results in Table 3-1 show similar

concentrations at both the M25 and M60 sites. A very high concentration was reported

on the 11th February 2010 at the M25 site, an investigation showed that there were no

other AURN sites with high Benzene levels on this date which suggests that the high

concentration is due to the BTEX tube being contaminated either at site or during

analysis. This result was removed prior to the calculation of the annual average.

Table 3-12: Compliance with UK Air Quality objectives, benzene

Statistic Objective

concentration

Permitted number of

exceedances M25 M60

Annual mean 5 g/m3 n/a 0.30 0.32

Data capture (% of

calendar year)

n/a n/a 85 65*

*BTEX monitoring discontinued from October. Data capture for the monitoring period was 80%.

3.7 Carbon monoxide

Concentrations of carbon monoxide (CO) are recorded as 15-minute means by the

continuous analysers. 1-hour mean concentrations were calculated from the 15-minute

mean data for comparison with the UK Air Quality objective concentration. Time-series

plots of the running 8-hour mean concentration of CO are presented in Volume II of this

report. The running 8-hour mean concentrations for carbon monoxide were less than 1

mg/m3 for majority of the year at the M25, M4 and M60 sites and also for monitoring

period in Bell common Tunnel. There were no significant peaks at any of the sites.

Table 3-13 shows that there were no exceedances of the running 8-hour mean objective

for CO at any of the monitoring sites in 2010. High data capture rates were achieved for

CO at the M25, M4 and M60 motorway sites. Minor disruptions to data collection caused

by power failures or instrument faults are discussed in Section 2.

Table 3-13: Compliance with UK Air Quality objectives, carbon monoxide (CO)

Statistic Objective

concentration

Permitted number of

exceedances M25 M4 M60 Bell Common

Maximum running 8-hour mean

10 mg/m3 n/a 1.8 1.9 1.8 1.8


n/a n/a 90 94 90 18*

* Bell Common Tunnel site in place between 27/10/2010 and 31/12/2010 (data capture 99.8%)

3.8 Lead

Concentrations of selected heavy metals are monitored at the M25 motorway site. The

measurement method follows that employed on the UK Heavy Metals Monitoring

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Network in line with Directive 2004/107/EC (EC, 2004). The UK Air Quality Regulations

set an objective annual mean concentration for lead equal to or less than 0.25 g/m3.

Concentrations of other heavy metals which are not covered by the UK Air Quality

Regulations are discussed in section3.9.5.

The annual mean concentration of lead recorded at the M25 site in 2010 was well below

the UK Air Quality objective. A high data capture rate was achieved for lead monitoring

in 2010.

Table 3-14: Compliance with UK Air Quality objectives, lead

Statistic Objective


of exceedances M25

Annual mean 0.25 g/m3 n/a 0.010

Data capture (% of calendar

year) n/a n/a 100

3.9 Pollutants not covered by the UK Air Quality Regulations

Concentrations of a number of pollutants not covered by the UK Air Quality Regulations

are recorded at sites within the Highways Agency long term roadside monitoring

network. Whilst these pollutants are not covered by UK legislation, guidance values for

safe levels of human exposure exist and it is therefore considered useful to monitor

concentrations. In addition, monitoring over an extended time period can provide a

useful indication of emissions trends at roadside sites.

3.9.1 Polycyclic aromatic hydrocarbons

PAH monitoring in the Highways Agency network began in 2003 at the M25 site and in

2004 at the M60 site. Benzo[a]pyrene (B[a]P) is the compound that is considered to be

representative for the cancer risk associated with the whole PAH mixture (EPAQS, 1999).

An annual mean concentration for B[a]P of 0.25 ng/m3 is the value listed in the UK Air

Quality Strategy (Defra, 2007) as an objective for PAH. This pollutant is not, however,

covered by EU Daughter Directives on Air Quality and is not therefore transposed into UK

law through the UK Air Quality Regulations.

There was a low data capture rate at both sites during 2010. This was largely due to

problems with partisol filters jamming during exchange at both sites. At the M25 site

there was prolonged data loss between 12/04/2010 and 04/06/2010 when a number of

onsite instrument repairs failed and the instrument was removed and sent away for

repair. There were also three other periods where the partisol filters jammed between

25/06/2010 and 05/07/2010, 19/09/2010 and 22/10/2010 and 30/11/2010 and

20/12/2010. The partisol did not jam for the whole periods but the number of filters

correctly collecting sample was insufficient to send away for analysis. There was missing

data at the beginning of January at both sites due to the filters running out over the

Christmas break and then site visits delayed due to heavy snowfall. At the M60 site

there was prolonged data loss between 28/03/2010 and 02/08/2010 due to an

instrument fault which took the service company a long time to fix. There was also a

filter jam between 18/08/2010 and 07/09/2010.

Table 3-15 presents the annual mean concentrations of B[a]P measured at the M25 and

M60 sites during 2010. The UK Air Quality Strategy provisional objective was exceeded

at both sites. This can only be used as a guide level as the data capture rate at the sites

was very low during 2010.

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Table 3-15: Compliance with UK Air Quality provisional objective,

benzo[a]pyrene (B[a]P)

Statistic Objective

concentration

Permitted number of

exceedances M25 M60

Annual mean 0.25 ng/m3 n/a 0.26 0.34

Data capture (% of

calendar year)

n/a n/a 65.4 42.3

3.9.2 Aldehydes

Aldehydes are not included in the UK Air Quality Regulations. Human health effects

(including eye, skin and respiratory irritation and neurophysical and behavioural changes

(at particularly high levels)) resulting from exposure to aldehydes (particularly

formaldehyde) provide the reasons for measuring this group of pollutants. A report

prepared for the Committee on the Medical Effects of Air Pollution (COMEAP) records

threshold levels of exposure to formaldehyde being associated with sensory irritation in

the general population concentrations of approximately 0.6-1.2 mg/m3 for formaldehyde

and less than 90 mg/m3 for acetaldehyde6.

The monitoring of aldehydes at the M25 and M60 sites was stopped on 2nd August 2010

due to financial constraints on the project. Annual mean concentrations of formaldehyde

and acetaldehyde recorded at the M25 and M60 motorway sites in 2010 are presented in

Table 3-16. Concentrations were well below the recommended guidelines at both sites

during 2010. The data capture rate at both the M25 and M60 was 100 percent for the

period monitored.

Table 3-16: Annual mean concentration, acetaldehyde and formaldehyde

Pollutant

COMEAP recommended

maximum concentration

Statistic M25 M60

Acetaldehyde 90 mg/m3 Annual mean (mg/m3) 0.00057 0.00005

Formaldehyde 0.1-0.2 mg/m3 Annual mean (mg/m3) 0.00040 0.00043

Aldehydes n/a Data capture (% of

calendar year) 58 58

3.9.3 Total hydrocarbons

Total hydrocarbons and Methane are not included in the UK Air Quality Regulations or

Environment Agency Guidelines. However the UK government is committed to reduce

emissions of methane under the United Nations Framework Convention on Climate

Change (Kyoto Protocol). The target for the UK is to achieve a reduction of the global

warming potential of six greenhouse gases including methane of 12.5% by 2008-2012

(based on 1990 emissions estimates). Concentrations of total hydrocarbons (THC) and

methane (CH4) are measured at the M25 and M60 motorway sites. Long term problems

with the Flame Ionisation Detector (FID) method of data collection have meant that

results for non-methane hydrocarbons (NMHC) could not be validated and have not been

6 http://www.advisorybodies.doh.gov.uk/comeap/statementsreports/aldehydes-imperialcollreview.pdf

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TRL 24 RPN744 (I)

presented in this report. As no cost effective replacements for continuous ambient

hydrocarbon measurements could be found the decision was made to discontinue

monitoring NMHC. Data capture rates for concentrations of CH4 were slightly lower due

to a number of reasons including the flame going out on the FID, power cuts and at the

M60 the logger fault. Section 2 outlines when there is missing data and the explanation.

Table 3-17: Annual mean concentration, methane (CH4)

Statistic M25 M60

Annual mean (µg/m3) 0.97 1.56

Calibrated data capture (% of calendar year) 86 85

3.9.4 Ammonia

Ammonia (NH3) concentrations are recorded at the M4, M25 and M60 motorway sites

using passive diffusion tubes exposed at approximately 2-weekly intervals. The exposure

period was changed from 2-weekly to monthly sampling intervals at the beginning of

August. The change in sampling intervals was to make financial savings so that

monitoring could continue until the end of the year. Also an additional background site

was started at the M60 site at the beginning of September.

This pollutant is not included in the UK Air Quality Regulations. The Environment Agency

recommends a long term Environmental Assessment Level (EAL) of 180 µg/m3 as an

annual average7. The annual averages recorded at the Highways Agency roadside

monitoring sites in 2010 were well below this value.

At the M25 and M60 sites, triplicate tubes were deployed at two and three locations

respectively. At the M25 site, one set of tubes was deployed close to the inlet at the

roadside and the second set was deployed in the field at the rear of the monitoring

station 66m from the hard shoulder. A transact was deployed at 90 degrees to the

motorway at the M60 site, one set of tubes was deployed at the hard shoulder, the

second set was deployed at the inlet 18m from the roadside and the third set was

deployed at 39m from the hard should. At the M4 site, tubes were only located at the

hard shoulder at the sample inlet as no suitable background location was identified.

High data capture rates (i.e. above 90%) for ammonia were achieved at all three sites in

2010. The data capture rate at the M60 background site was also one hundred percent

for the monitoring period. One batch of samples from the M4 site in March was found to

have been removed from the inlet clips which resulted in a small period of data loss.

Table 3-18,Table 3-19 and Table 3-20 show the levels of ammonia found at the M60

roadside site are higher than the roadside (inlet) levels found at the M4 and M25 sites.

This is consistent with previous year’s results; however the concentrations in 2010 at the

M60 roadside site have decreased from an annual mean concentration of 12.9 µg/m3 in

2009. The annual mean concentration of ammonia at the inlet at the M60 site is similar

to those found at the M4 and M25 inlets; however the M60 inlet is 18m from the

roadside. The reason for the elevated levels of ammonia at the M60 roadside site is

unknown; there are no other known local sources however this result is consistent with

previous year’s results. The M60 Background site ammonia concentrations are lower

than the results at the M25 background site. The reason for the slightly higher ammonia

levels at the M25 background site could be due to the sheep that occasionally reside in

the field where the diffusion tubes are located.

7 Personal communication between TRL Ltd and Environment Agency, July 2010

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TRL 25 RPN744 (I)

Table 3-18: M25 Annual mean concentration, ammonia (NH3)

Site

Environmental Assessment Level (EAL)

annual mean

µg/m3

Annual mean

(µg/m3)

Data capture (% of

calendar year)

Distance from hard

shoulder (m)

Grid reference

(OS)

Sample tube

height

(m)

Roadside tube average (µg/m3)

180 5.93 100 2m 502807,173568 1.9 m

Background tube average (µg/m3)

180 7.78 100 50m 502745,173520 1.7m

Table 3-19: M4 Annual mean concentration, ammonia (NH3)

Site


annual mean

µg/m3

Annual mean

(µg/m3)

Data capture (% of

calendar year)

Distance from hard

shoulder (m)

Grid reference

(OS)

Sample tube

height

(m)


180 5.63 94 0.5m 469937,169428 1.5m

Table 3-20 M60 Annual mean concentration, ammonia (NH3)

Site


annual mean

µg/m3

Annual mean

(µg/m3)

Data capture (% of

calendar year)

Distance from hard

shoulder (m)

Grid reference

(OS)

Sample tube

height

(m)


180 8.62 100 1m 381294,405022 1.5m

Inlet tube average (µg/m3)

180 5.51 100 18m 381310,405004 3.5m

Background tube average (µg/m3)

180 3.75 22* 39m 381309,404983 2.1m

*Monitoring period 7/09/2010 to 31/12/2010

3.9.5 Heavy metals

Concentrations of selected heavy metals are recorded at the M25 motorway site. Lead is

included in the UK Air Quality Regulations and results obtained for this pollutant at the

M25 site in 2010 are discussed in Section 3.8. Annual mean concentrations of arsenic,

cadmium and nickel are also subject to target values under the 4th Daughter Directive

(2004/107/EC)8. Target values set under this directive require member states to take all

cost effective abatement measures but do not require them to undertake any measures

entailing disproportionate costs. Target values are 6 ng/m3, 5 ng/m3 and 20 ng/m3 for

8 http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32004L0107:EN:NOT

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arsenic, cadmium and nickel respectively. Annual mean concentrations of arsenic,

cadmium and nickel recorded at the M25 site remained well below these target values in

2010 (see Table 3-21).

Table 3-21: Annual mean concentration, heavy metals

Pollutant Statistic Target Value M25

Arsenic

Annual mean (ng/m3) 6 ng/m3 0.74

Data capture (% of calendar year)

n/a 100

Cadmium


Data capture (% of calendar year) n/a 100

Nickel


Data capture (% of calendar year) n/a 100

3.9.6 Hydrogen sulphide

Concentrations of hydrogen sulphide (H2S) are measured at the M25 and M60 motorway

sites. This pollutant is not included in the UK Air Quality Regulations. The Environment

Agency9 recommends a long term EAL of 140 µg/m3. Annual average concentrations of

H2S recorded at the Highways Agency roadside monitoring sites in 2010 were well below

this value. High data capture rates (i.e. above 90%) for H2S were achieved at the M25

site in 2010. The data capture rate at the M60 site was slightly lower due to a number of

issues including power failures and instrument faults as discussed in Section 2.4.

Table 3-22: Annual mean concentration, hydrogen sulphide (H2S)

Statistic

Environmental Assessment Level (EAL) long term

µg/m3

M25 M60

Annual mean (µg/m3) 140 4.96 8.15


n/a 95 85

3.10 Traffic data

In addition to pollutant concentrations, information on total traffic flow only are collected

by Automatic Traffic Counters (ATCs) at the M4, M25, and M60 sites (see Table 3-23). As

a result of ongoing refurbishment work of the Bell Common tunnel traffic data was not

available. Traffic flows recorded in 2010 at each monitoring site are presented together

with historical datasets in Volume II.

9 http://publications.environment-agency.gov.uk/pdf/GEHO1105BJXV-e-e.pdf

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Table 3-23: Annual average daily and hourly traffic flow

Statistic M25 M4 M60

Annual average daily traffic flow CW 97632 EB 54869

WB 54339

CW 80390

ACW 79405 ACW 98410

Annual average vehicles per hour CW 4183 EB 2286

WB 2264

CW 3350

ACW 3309 ACW 4192

Data capture (% of calendar year) CW 97 EB 75

WB 86

CW 92

ACW 90 ACW 98

CW: clockwise; ACW: anti-clockwise; EB: Eastbound; WB: Westbound

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4 Summary

This report provides a summary of air pollutant concentrations, meteorological data and

traffic flows measured at four motorway sites during the calendar year 2010 as part of

the Highways Agency long term roadside monitoring network.

The report compares concentrations of pollutants with objectives set out by the UK Air

Quality Regulations. The following exceedances have been recorded during 2010:

The annual mean NO2 objective concentration of 40 µg/m3 was exceeded at the

M25, M4 and M60 monitoring sites.

There were no exceedances of the 1-hour mean NO2 objective concentration of

200 µg/m3.

Exceedance of the running 8-hour mean O3 objective of 100 µg/m3 occurred at

the M60 and M4 sites.

There were no exceedances of the relevant objectives for SO2, PM10, benzene, CO

or lead at any of the monitoring sites.

Monitoring at Bell Common Tunnel site was only for two months between October and

December and therefore the results should be treated with caution when comparing with

other yearly data sets. During the two month monitoring period the NO2 annual mean

objective and one hour mean objective were both exceeded which provides an indicative

result for the expected results for 2010.

Concentrations of pollutants not covered by the UK Air Quality Regulations are reported

and discussed with reference to Environment Agency guidelines of other health

standards where applicable.

The provisional UK Air Quality objective for PM2.5 was met at all sites.

The provisional UK Air Quality objective for benzo[a]pyrene was exceeded at both

sites. It should be noted that these results are only indicative as due to technical

faults the data capture rate at both the M25 and M60 sites is low.

There were no exceedances of Environmental Assessment Level guideline values

for NH3 or H2S reported at the Highways Agency monitoring sites in 2010.

There were no exceedances of target values for heavy metals (arsenic, cadmium

and nickel) recorded at the M25 site 2010.

There were no exceedances of the COMEAP recommended maximum exposure

value for aldehydes (acetaldehyde and formaldehyde) recorded at the Highways

Agency sites in 2010.

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TRL 29 RPN744 (I)

References

Air Quality (England) Regulations 2000. Statutory Instrument 2000 No. 928.

http://www.opsi.gov.uk/si/si2000/20000928.htm

Air Quality (England) (Amendment) Regulations 2002. Statutory Instrument 2002. No.

3043. http://www.opsi.gov.uk/si/si2002/20023043.htm

Boulter P G, McCrae I S and Green J (2007). Primary NO2 emissions from vehicles in the

Hatfield and Bell Common Tunnels. TRL report PPR 262. TRL, Wokingham.

Defra (2007). The Air Quality Strategy for England, Scotland, Wales and Northern

Ireland: July 2007, Cm 7169 NIA 61/07-07. Department for Environment, Food and

Rural Affairs, the Scottish Executive, Welsh Assembly Government and the Department

of the Environment for Northern Ireland. The Stationary Office, London.

EC (2004). Directive 2004/107/EC of the European Parliament and of the Council relating

to arsenic, cadmium, mercury, nickel and polycyclic aromatic hydrocarbons in ambient

air.

EPAQS (1999). Polycyclic aromatic hydrocarbons. Expert Panel on Air Quality Standards.

Report for the former Department of the Environment, Transport and the Regions. DETR,

London.

Green J (2005). Impact of reduced emissions on air quality: the monitoring of aromatics

and aldehydes 1995 to 2003. TRL report UPR SEA/02/05. TRL, Wokingham.

Highways Agency (2007). The Highways Agency roadside air pollution monitoring

network 2005. TRL report PPR 192. TRL, Wokingham.


network 2006. TRL report PPR 371. TRL, Wokingham.


network 2002. TRL report UPR SE/020/04. TRL, Crowthorne.


network 1992 to 2001. TRL report PR SE/742/03. TRL, Crowthorne.


network 2003. TRL report UPR SE/145/04. TRL, Wokingham.


network 2008 Volume II. TRL report RPN 744. TRL, Wokingham.

WHO (2000). Air quality guidelines for Europe, 2nd edition. World Health Organisation

Regional Publications, No. 91. WHO.



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Appendix A Figures and locations of monitoring sites

A.1 M4 (Theale 2), Pinglewood

A.1.1 Ordnance Survey map

© Crown copyright. All rights reserved. License No. AL100021177

M4 Theale 2

N

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A.1.2 Site photos

A.1.2.1 M4 monitoring station

A.1.2.2 Selection of instruments inside the M4 monitoring station

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A.2 M25, Bell Common Tunnel



Bell Common

Tunnel

N

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A.2.2 Site photos

A.2.2.1 Bell Common Tunnel monitoring station

A.2.2.2 Selection of instruments inside the Bell Common Tunnel monitoring station

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A.3 M25 (M25B), Staines



M25B

N

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A.3.2 Site photos



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A.4 M60, Kirkhams



M60

N

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A.4.2 Site photos



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Appendix B Calibration and maintenance records

B.1 M4 (Theale 2), Pinglewood

DATE Reason for visit

Notes/Actions taken

04/01/10 Span/Zero check. By-pass DFU’s on both TEOM units replaced.

19/01/10 Span/Zero check. O3 analyser swapped out.

05/02/10 Span/Zero check. NH3 tubes swapped out.

19/02/10 Span/Zero check. PM2.5 TEOM pump swapped out. NH3 tubes swapped out.

05/03/10 Span/Zero check. By-pass DFU’s replaced on both TEOM units. NH3 tubes swapped out.

19/03/10 Span/Zero check. PM10 flow alarm. PM10 TEOM swapped out. NH3 tubes swapped out.

16/04/10 Span/Zero check. NH3 tubes collected. Cleared ‘reset system’ on all API units after power cut/fluctuations.

06/05/10 Span/Zero check. Cleared ‘reset system’ on all API units after power failure. NH3 tubes deployed.

19/05/10 Span/Zero check. PM10 heads swapped out. NH3 tubes collected.

01/06/10 Span/Zero check. NH3 tubes swapped out. Two free standing A/C units working well.

15/06/10 Interim visit. No power to site. NH3 tubes swapped out.

22/06/10 Interim visit. Still no power to site. NH3 tubes swapped out.



06/08/10 Span/Zero check. -


03/09/10 Span/Zero check. NH3 tubes swapped out. Free standing A/C units working well.

05/10/10 Span/Zero check. PM10 and PM2.5 heads swapped out.

25/10/10 Span/Zero check. TEOM flow alarm on PM2.5, changed filter. NH3 tubes swapped out.



10/12/10 Span/Zero check & O3

cals.

O3 calibration carried out.


B.2 M25, Bell Common Tunnel


Notes/Actions taken





B.3 M25 (M25B), Staines


Notes/Actions taken

12/01/10 Span/Zero check. Diffusion tubes and filters changed.

21/01/10 Interim visit. Diffusion tubes and filters changed.



11/02/10 Span/Zero check. H2S & SO2 swapped out. Partisol 2025 PM10 head swapped

out. Hyg. gas bottle swapped out. Diffusion tubes and

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filters changed.

18/02/10 Interim visit. CO analyser fault, power reset & removed/replaced P/S

board, still logging ok. Diffusion tubes and filters changed.

25/02/10 Span/Zero check. CO analyser - no response to gas. Removed it for repair.

Diffusion tubes and filters changed.


11/03/10 Span/Zero check. Cleared ‘system reset’ on API units due to power cut. FID

re-lit due to flame out when power cut took place. Diffusion tubes and filters changed.

18/03/10 Interim visit. CO analyser installed, calibration done in workshop before

installation. Diffusion tubes and filters changed.

19/03/10 O3 swap out. HORIBA O3 unit swapped for API400A O3 unit.

23/03/10 Equipment serviced.

Service of all equipment took place.

25/03/10 Span/Zero check. Diffusion tubes and filters changed. PM10 heads swapped

out. Partisol 2025 re-started due to filter exchange failure. Hyg. gas bottle swapped out

01/04/10 Interim visit. TEOM PM2.5 flow fault, power reset, filter changed and all connections checked; service engineer has recently been.


08/04/10 Span/Zero check. Partisol filter exchange failed; filter shuttled through and

re-started run. O3 warning; eventually cleared. All recently serviced. Diffusion tubes and filters changed.

16/04/10 Interim visit.

Warning on NOx; fan re-fitted, now working well. Warning on O3; service engineer to replace lamp asap.

Partisol filter exchange failed again; filter shuttled through and unit re-started.

19/04/10 O3 swap out & A/C

install. API O3 faulty; swapped out with HORIBA unit (left API for

service engineer to fix).


28/04/10 Interim visit. Warnings on H2S & SO2; checked operation & restarted.

NOx developed same fault while at site, fan had fallen off, replaced & fixed securely, restarted, all ok.

05/05/10 Span/Zero check. Warning on NOx unit, pump swapped out. Hyg. gas bottle

swapped out. Diffusion tubes and filters changed.

18/05/10 Span/Zero check. PM sample heads swapped out for cleaned units. Partisol 2025 swapped out due to repeated filter exchange fail.


04/06/10 Span/Zero check. HORIBA O3 swapped out; repaired API400A installed.


11/06/10 Interim visit. No issues

16/06/10 Span/Zero check. Hyg. bottle for FID swapped out. Partisol filter exchange failed, unit ser running again. Diffusion tubes and filters

changed.

24/06/10 Interim visit. NOx pump swapped out. Partisol filters swapped out. O3

scrubber swapped out.

05/07/10 Site issues.

PM2.5 TEOM flows mobile – control box swapped out, all setting checked and changed to match removed unit.

Solarimeter swapped out for new unit. Roof mounted A/C serviced by engineer. Diffusion tubes and filters changed.



23/07/10 O3 span check. No issues

30/07/10 Interim visit. FID flame out, hyg. gas bottle swapped out and FID re-lit

ok. Diffusion tubes and filters changed.

05/08/10 Span/Zero check. H2S & SO2 pump swapped out due to occasional noise from

bearings. PM2.5 head swapped out. Diffusion tubes and filters changed.

12/08/10 Interim visit. CO pump swapped out for service. Diffusion tubes and

filters changed.


26/08/10 Interim visit. No issues


10/09/10 Interim visit. FID hyg. gas had run out, bottle replaced and FID re-lit ok.


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14/10/10 Interim visit. H2S & SO2 system reset warning, cleared ok.

Hyg. gas bottle swapped out.

21/10/10 Span/Zero check. TEOM PM10 head swapped out. Diffusion tubes and filters

changed.

28/10/10 Interim visit. FID gave negative values on sample but flame was lit (?).

04/11/10 Span/Zero check. NOx swapped out temperature warning. FID had no

response to gas – removed for investigation. Diffusion tubes and filters changed.

08/11/10 NOx re-install. NOx re-installed after repairs


25/11/10 Interim visit. Partisol filter exchange failed; 1 cassette forced through

and unit set running again.

09/12/10 Span/Zero check. FID re-installed. O3 cals carried out. Diffusion tubes and

filters changed.


22/12/10 Span/Zero check. Comms checked. FID hyg, bottle swapped for full to cover holiday period. H2S & SO2 temp warning, unit calibration

checks ok.

B.4 M60, Kirkhams


Notes/Actions taken

18/01/10 Span/Zero check. NH3 tubes swapped out. Partisol filters running ok.

01/02/10 Span/Zero check. No H2S gas. No comms to Partisol.

16/02/10 Span/Zero check. Partisol filters running ok.

01/03/10 Span/Zero check. Changed modem.

15/03/10 Span/Zero check. PM10, PM2.5 and Partisol sample heads changed.

29/03/10 Span/Zero check. BTEX tubes changed. Partisol being repaired.

14/04/10 Tubes changed Partisol, BTEX, and DNPH tubes changed.


10/05/10 Span/Zero check. Partisol being repaired.

24/05/10 Span/Zero check. Tubes to be changed later in the week.

07/06/10 Span/Zero check. Partisol working ok.


19/07/10 Span/Zero check. NH3 tubes collected. Cleared partisol jam.



07/09/10 Span/Zero check. NH3 and NO2 tubes distributed.


14/10/10 Span/Zero check. Repaired regulator value assemblies.

15/11/10 Span/Zero check. Partisol jammed, no filters passed, reset, now ok. Faulty

modem on Partisol. Repaired CO filter assembly.


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Appendix C Meteorological data

Meteorological data were collected at three of the four current monitoring sites. These

data were recorded to enable analysis of long term trends in emissions and pollutant

concentrations at each monitoring site.

C.1 Meteorological data

Statistic M25 M4 M60

Annual average wind speed (m/s) 1.89 1.41 0.22

Annual maximum wind speed (m/s) 8.41 8.49 3.26

Annual minimum wind speed (m/s) 0.15 0.00 0.00

Wind speed data capture (% of calendar year)

99.8 95.0 88.6

Annual average wind direction (degrees from north)

182.02 125.27 175.05

Wind direction data capture (% of calendar year)

99.8 95.0 93.3

Annual average temperature (⁰C) 11.25 10.03 10.23

Annual maximum temperature (⁰C) 30.38 31.46 27.55

Annual minimum temperature (⁰C) -8.19 -10.79 -7.75

Temperature data capture (% of calendar year)

99.8 95.0 72.3

Annual average relative humidity (%) 61.49 62.16 66.59

Annual maximum relative humidity (%) 92.08 99.9 92.03

Annual minimum relative humidity (%) 0.70 7.80 4.15

Relative humidity data capture (% of calendar year)

99.8 94.9 93.3

Annual average solar radiation (W/m2) 134.29 - -

Annual maximum solar radiation (W/m2)

1012.40 - -

Annual minimum solar radiation (W/m2) 0.00 - -

Solar radiation data capture (% of calendar year)

92.1 - -

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Appendix D Air Quality Strategy objectives

D.1 UK Air Quality Strategy objectives

Pollutant Objective Compliance date

Nitrogen dioxide (NO2)

Hourly mean concentration should not exceed 200 μg/m3 more than 18 times a year

Annual mean concentration should not exceed 40 μg/m3 31 December 2005

Particulate matter,

expressed as PM10

24-hour mean concentration should not exceed 50 μg/m3 more than 35 times a year

Annual mean concentration should not exceed 40 μg/m3 31 December 2004

Particulate

matter,

expressed as PM2.5

Annual mean concentration should not exceed 25 μg/m3 in UK 2020

Benzene Running annual mean concentration should not exceed 16.25

μg/m3

Annual mean concentration should not exceed 5 μg/m3

31 December 2003

31 December 2010

1,3-butadiene

Running annual mean concentration should not exceed 2.25 μg/m3

31 December 2003

Carbon monoxide

(CO)

Maximum running 8-hour mean concentration should not exceed 10 mg/m3

31 December 2003

Polycyclic aromatic

hydrocarbons (PAH)

Annual mean concentration should not exceed 0.25 ng/m3 31 December 2010

Lead (Pb) Annual mean concentration should not exceed 0.5 μg/m3 Annual mean concentration should not exceed 0.25 μg/m3

31 December 2004

31 December 2008

Sulphur dioxide (SO2)

Hourly mean concentration of 350 μg/m3 not to be exceeded more than 24 times a year

24-hour mean of 125 μg/m3 not to be exceeded more than 3 times a year

15-minute mean of 266 μg/m3 not to be exceeded more than

35 times a year

31 December 2004

31 December 2004

31 December 2005

Ozone (O3) 8-hour mean of 100 μg/m3 not to be exceeded more than 10

times a year 31 December 2005

Project Report

TRL 43 RPN744 (I)

Appendix E Conversion factors

E.1 Conversion factors

Pollutant Conversion factor

Ozone 1 ppb = 2.00 µg/m3

Nitrogen oxide (as NO2 equivalent)

1 ppb = 1.91 µg/m3

Nitrogen dioxide 1 ppb = 1.91 µg/m3

Sulphur dioxide 1 ppb = 2.66 µg/m3

Methane 1 ppm = 0.67 mg/m3

Non-methane

hydrocarbons 1 ppm = 0.58 mg/m3

Carbon monoxide 1 ppm = 1.16 mg/m3

Ammonia 1 ppb = 0.71 µg/m3

Hydrogen sulphide 1 ppb = 1.42 µg/m3

Documents

The Highways Agency roadside air pollution monitoring network report …assets.highways.gov.uk/specialist-information/knowledg… · · 2013-04-30Transport Research Laboratory The