The Highways Agency roadside air pollution monitoring network report Volume I

Transcription

1 Transport Research Laboratory The Highways Agency roadside air pollution monitoring network report Volume I by J Pittman, D Gardiner and E Anderson CPR1095 (I) 443 (1308) HALC PROJECT REPORT

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3 Transport Research Laboratory PROJECT REPORT CPR1095 (I) The Highways Agency roadside air pollution monitoring network report Volume I by J Pittman, D Gardiner and E Anderson Prepared for: Project Record: Client: 443 (1038) HALC Impact of reduced emissions on air quality 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

4 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 TRL CPR1095

5 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 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 (NO X ), nitric oxide (NO), nitrogen dioxide (NO 2 ) were measured at all sites. In addition, concentrations of total hydrocarbons (methane (CH 4 ) and non-methane hydrocarbons (HC)), ammonia (NH 3 ), particulate matter (PM 10 and PM 2.5 ) and ozone (O 3 ) were measured at the M4, M25 and M60 motorway sites and concentrations of sulphur dioxide (SO 2 ), hydrogen sulphide (H 2 S), 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 NO 2 annual mean objective concentration of 40 g/m 3 and the running 8- hour mean objective for O 3 was exceeded at the M4 and M60 site. Conversely, there were no exceedances of the relevant objectives for SO 2, PM 10, PAH, benzene, CO or lead at any of the monitoring sites during 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/m 3 mg/m Max. of 18 exceedances of 1-hr mean of 200 g/m 3 No. of exceedances NO 2 Annual mean of 40 g/m 3 g/m O 3 Max. of 10 exceedances of running 8-hr mean of 100 g/m g/m 3 TEOM VCM adjusted PM 10 Max. of 35 exceedances of 24-hr mean of 50 µg/m 3 No. of exceedances TRL CPR1095

6 Pollutant Objective Unit M25 M4 M60 Bell Common Annual mean of 40 g/m 3 40 g/m Max. 3 exceedances of 24-hr mean of 125 µg/m 3 No. of exceedances SO 2 Max. 24 exceedances of 1- hr mean of 350 µg/m 3 No. of exceedances Max. 35 exceedances of 15- min mean of 266 µg/m 3 No. of exceedances 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). TRL CPR1095

7 Contents List of Tables iii 1 Introduction 4 2 Data collection M4 (Theale 2), Pinglewood M25, Bell Common Tunnel M25 (M25B), Staines M60, Kirkhams Quality assurance and quality control Site visits Data checking Data calibration and ratification Data analysis 11 3 Compliance with UK Air Quality objectives and permitted exceedances Nitrogen dioxide Sulphur dioxide Ozone Particulate Matter PM PM Aromatic hydrocarbons (BTEX) Carbon monoxide Lead Pollutants not covered by the UK Air Quality Regulations Polycyclic aromatic hydrocarbons Aldehydes Total hydrocarbons Ammonia 24 *Monitoring period 7/09/2010 to 31/12/2010Error! Bookmark not defined Heavy metals Hydrogen sulphide 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 TRL i RPN744 (I)

8 Appendix D Air Quality Strategy objectives 42 Appendix E Conversion factors 43 TRL ii RPN744 (I)

9 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/ 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 (NO 2 ) Table 3-2: Annual mean nitric oxide (NO) concentration Table 3-3: Annual mean total oxides of nitrogen (NO X ) concentration Table3-4: M25 NO 2 diffusion tube results Table3-5: M60 NO 2 diffusion tube results Table 3-6: Compliance with UK Air Quality objectives, sulphur dioxide (SO 2 ) Table 3-7: Compliance with UK Air Quality objectives, ozone (O 3 ) Table 3-8: Compliance with UK Air Quality objectives, particulate matter (PM 10 ) Table 3-9: Compliance with Provisional UK Air Quality objectives, particulate matter (PM 2.5 ) Table 3-10: Compliance with UK Air Quality objectives, benzene Table 3-11: Compliance with UK Air Quality objectives, carbon monoxide (CO) Table 3-12: Compliance with UK Air Quality objectives, lead Table 3-13: Compliance with UK Air Quality provisional objective, benzo[a]pyrene (B[a]P) Table 3-14: Annual mean concentration, acetaldehyde and formaldehyde Table 3-15: Annual mean concentration, methane (CH 4 ) Table 3-16: Annual mean concentration, ammonia (NH 3 ) Error! Bookmark not defined. Table 3-17: Annual mean concentration, heavy metals Table 3-18: Annual mean concentration, hydrogen sulphide (H 2 S) Table 3-19: Annual average daily and hourly traffic flow TRL iii RPN744 (I)

10 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 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 website 1, 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 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 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 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 TRL 4 RPN744 (I)

11 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 (PM 10 ), and the second monitor configured to measure particulate matter with an aerodynamic diameter of less than 2.5 microns (PM 2.5 ). 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 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 (NO X ), nitrogen dioxide (NO 2 ), nitric oxide (NO) Chemiluminescence Ozone (O 3 ) Ultra violet (UV) absorption Particulate matter (PM 10 and PM 2.5 ) Heated gravimetric - TEOM Ammonia (NH 3 ) 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 TRL 5 RPN744 (I)

12 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 23 rd 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 M25, Bell Common Tunnel The monitoring site on the M25 motorway at the Bell Common Tunnel was installed in January 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 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 Data collection was only carried out for two months in 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 , Road type Suburban motorway Commencement date January 2007 Carbon monoxide (CO) Infra red (IR) absorption Total oxides of nitrogen (NO X ), nitrogen dioxide (NO 2 ), nitric oxide (NO) Chemiluminescence Traffic flow Automatic Traffic Counter (ATC) 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 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 TRL 6 RPN744 (I)

13 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 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 Road type Rural motorway Commencement date February 2004 PM 10 inlet height above ground level 2.7 m PM 10 inlet height above enclosure roof 0.7 m PM 2.5 inlet height above ground level 2.4 m PM 2.5 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 Gaseous residence time 0.8 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 Carbon monoxide (CO) Infra red (IR) absorption Total oxides of nitrogen (NO X ), nitrogen dioxide (NO 2 ), nitric oxide (NO) Chemiluminescence Ozone (O 3 ) Ultra violet (UV) absorption Total hydrocarbons (THC), methane (CH 4 ), nonmethane hydrocarbons (NMHC) Flame ionisation detector (FID) Sulphur dioxide (SO 2 ), hydrogen sulphide (H 2 S) Ultra violet (UV) fluorescence Particulate matter (PM 10 and PM 2.5 ) Heated gravimetric TEOM Ammonia (NH 3 ) Passive diffusion tubes Nitrogen dioxide (NO 2 ) 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 Meteorological conditions Wind speed, wind direction, temperature, relative humidity, solar radiation Traffic flows Automatic Traffic Counter (ATC) During 2010, the M25 motorway site operated continuously with the following disruptions to data collection: TRL 7 RPN744 (I)

14 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. NO X 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 28 th 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 SO 2 analyser was serviced on the 23/03/2010 to 24/03/2010, no data is available during this period. Invalid SO 2 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 PM 2.5 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). Records of visits to the M25 monitoring site in 2010, including the reason for each visit and actions performed are presented in Appendix B M60, Kirkhams Monitoring began on the M60 motorway in May 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. TRL 8 RPN744 (I)

15 Table 2-4: Site information: M60, Kirkhams Site M60, Kirkhams Location Eastbound carriageway, east of junction 17 Grid reference SD Road type Suburban motorway Commencement date May 1999 Enclosure level above road surface Particulate inlet above ground level Particulate inlet above enclosure roof level Particulate inlet distance from hard shoulder Gaseous inlet above ground level Gaseous inlet above enclosure roof level Gaseous inlet distance from hard shoulder Gaseous manifold inlet flow rate Gaseous residence time Meteorological equipment above ground level Meteorological equipment above enclosure roof level Meteorological equipment distance from hard shoulder Carbon monoxide (CO) Total oxides of nitrogen (NO X ), nitrogen dioxide (NO 2 ), nitric oxide (NO) Ozone (O 3 ) Particulate matter (PM 10 ) Total hydrocarbons (HC) and methane (CH 4 ) Sulphur dioxide (SO 2 ), hydrogen sulphide (H 2 S) Ammonia (NH 3 ) Nitrogen dioxide (NO 2 ) Aromatic hydrocarbons BTEX Polycyclic aromatic hydrocarbons (PAH) Aldehydes Meteorological conditions Traffic flow 2.0 m 3.2 m 0.6 m 18 m 3.5 m 0.9 m 18 m 3.2 m/s 0.8 sec 6.8 m 4.2 m 18 m Infra red (IR) absorption Chemiluminescence Ultra violet (UV) absorption Heated gravimetric TEOM and Partisol Flame ionisation detector Ultra violet (UV) fluorescence Passive diffusion tubes Passive diffusion tubes (3 months) Pumped samples (gas chromatography) Particle phase by Partisol (gas chromatography) Pumped samples (high pressure liquid chromatography) Wind speed, wind direction, temperature, relative humidity Automatic Traffic Counter (ATC) During 2010, the M60 motorway site operated continuously with the following disruptions to data collection: 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. NO X 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 TRL 9 RPN744 (I)

16 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 SO 2 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 O 3 instrument service was carried out on the 04/03/2010, which resulted in a few hours data loss, and an O 3 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 Records of visits to the M60 monitoring site in 2010, including the reason for each visit and actions performed are presented in Appendix B 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 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 AURN 3. 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 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 TRL 10 RPN744 (I)

17 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 Data calibration and ratification Air pollutant data was ratified as per AURN recommended procedures 3. 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 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 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. TRL 11 RPN744 (I)

18 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 nonregulated pollutants are also presented and discussed in comparison with guidance values recommended by the Environment Agency Nitrogen dioxide Nitrogen dioxide (NO 2 ) 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 NO 2 concentrations for all sites are presented in Volume II of this report. The UK Air Quality Regulations provide two objectives for NO 2 ; the 1-hour mean concentration of 200 µg/m 3, which must not be exceeded more than 18 times per year, and the annual mean limit of 40 µg/m 3. 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 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 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 NO 2 were achieved at the M4 and M25 monitoring sites in 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 NO 2 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 TRL 12 RPN744 (I)

19 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 NO 2 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 NO 2 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 NO 2 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/m 3 to 120 µg/m 3 higher than concentrations recorded at the London Hillingdon site. These occasions coincided with winds from the north suggesting that the lower NO 2 concentrations at the Hillingdon site were as a result of the northerly wind moving through the monitoring location towards the M4. The NO 2 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 NO 2 concentrations in June corresponded to low ozone concentrations. It is suggested that the higher NO 2 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 NO 2 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, TRL 13 RPN744 (I)

20 Bury Roadside site, and the Salford Eccles site at the same time as the M60 site. It is suggested the increase NO 2 concentration recorded at this time was as a result of general pollution episode in the area. There was also a peak in NO 2 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. NO 2 concentrations reported at Bell Common Tunnel were between µg/m 3. 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/m 3, 49.7ug/m 3 and 61.6ug/m 3 respectively. Table 3-1: Compliance with UK Air Quality objectives, nitrogen dioxide (NO 2 ) Statistic Objective concentration Permitted number of exceedances M25 M4 M60 Bell Common 1 hour mean 200 g/m Annual mean ( g/m 3 ) 40 g/m 3 n/a * Calibrated data capture (% of calendar year) n/a n/a * 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 NO X 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/m 3 ) Calibrated data capture (% of calendar year) * TRL 14 RPN744 (I)

21 Table 3-3: Annual mean total oxides of nitrogen (NO X ) concentration Statistic M25 M4 M60 Bell Common Annual mean (µg/m 3 ) Calibrated data capture (% of calendar year) * * Tunnel refurbishment resulted in only 2 months of data in NO 2 Diffusion tube results During discussions with the Highways Agency in August 2010 it was agreed to deploy NO 2 diffusion tubes to support the oxides of nitrogen monitoring at the M25 and M60 sites. Two sets of triplicate NO 2 diffusion tubes were deployed to monitor NO 2 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 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/m 3 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 NO 2 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 NO 2 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 NO 2 background concentrations may be as a result of additional contributions from the aircraft movements. TRL 15 RPN744 (I)

22 Table3-4: M25 NO 2 diffusion tube results Date on Date off Period 1 02/09/ /09/2010 Period 2 30/09/2010 4/11/2010 Period 3 04/11/ /12/2010 Average Distance from hard shoulder (m) Grid reference (OS) Sample tube height (m) Roadside tube average (µg/m 3 ) Background tube average (µg/m 3 ) Analyser average (µg/m 3 ) m , m m , m m , m Table3-5: M60 NO 2 diffusion tube results Date on Date off Period 1 02/09/ /09/2010 Period 2 30/09/2010 4/11/2010 Period 3 04/11/ /12/2010 Average Distance from hard shoulder (m) Grid reference (OS) Sample tube height (m) Roadside tube average (µg/m 3 ) Background tube average (µg/m 3 ) Inlet tube average (µg/m 3 ) Analyser average (µg/m 3 ) m , m m , m m , m m , m 3.3 Sulphur dioxide Sulphur dioxide (SO 2 ) 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 SO 2 (measured as 15-minute, 1-hour and 24-hour means). Table 3-6 shows that there were no exceedances of the SO 2 objective concentrations at either monitoring site in The DEFRA air quality archive 5 was checked for comparison and there were no exceedances of any SO 2 objectives at sites in close proximity to the M25 or M60 sites. A high data capture rate for SO 2 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 SO 2 at the M25 site was less than 20ug/m 3 and there were no significant peaks in the data. 5 TRL 16 RPN744 (I)

23 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 SO 2 concentrations recorded were less than 30ug/m 3 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/m 3 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 SO 2 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 SO 2 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 (SO 2 ) Statistic Objective concentration Permitted number of exceedances M25 M60 15-minute mean 266 µg/m hour mean 350 µg/m hour mean 125 µg/m Calibrated 1- hour data capture (% of calendar year) n/a n/a Ozone Ozone (O 3 ) 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. O 3 is a secondary pollutant (i.e. it is not emitted directly from any source e.g. road traffic). O 3 forms in the lower atmosphere by reactions between volatile organic compounds (VOCs), CO and NO X in the presence of sunlight. O 3 reacts with NO emitted directly from vehicle exhausts to form secondary NO 2. At a roadside location, there is routinely an excess of NO and thus the limit to the formation of NO 2 is usually determined by the availability of O 3. During the summer months, higher concentrations of O 3 are typically observed as a result of increasing sunlight. Concentrations of NO 2 and O 3 measured at the Highways Agency roadside sites have been analysed in conjunction with each other in order to explain episodes of high and TRL 17 RPN744 (I)

24 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 O 3 were achieved at the M25 and M4 sites in 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 NO 2. 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 O 3 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 NO 2 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. TRL 18 RPN744 (I)

25 Table 3-8: Compliance with UK Air Quality objectives, ozone (O 3 ) Statistic Objective concentration Permitted number of exceedances M25 M4 M60 8-hour running mean Calibrated data capture (% of calendar year) 100 µg/m n/a n/a Bold type indicates exceedance of UK Air Quality objective 3.5 Particulate Matter Particulate matter concentrations for PM 10 and PM 2.5 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 PM 10 and the proposed objectives for PM 2.5, which are due to come into effect in High data capture rates (i.e. above 90%) for PM 10 and PM 2.5 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 PM 10 As discussed in previous monitoring reports (Highways Agency, 2008 & 2009), prior to processing and ratification, the raw PM 10 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 PM 10 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 PM 10 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. TRL 19 RPN744 (I)

26 Table 3-10: Compliance with UK Air Quality objectives, particulate matter (PM 10 ) Statistic Objective concentration Permitted number of exceedances Measurement method M25 M4 M60 24-hour mean 50 µg/m 3 35 TEOM adjusted (VCM) Annual mean (µg/m 3 ) 40 µg/m 3 n/a TEOM adjusted (VCM) Calibrated data capture (% of calendar year) n/a n/a Table 3-10 shows that the annual mean PM 10 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 PM 10 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 PM 10 are presented in Volume II of this report. The 24-hour mean concentration of PM 10 was typically between 10 and 40µg/m 3 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 (25 th to 27 th ), February (18 th ) and October (8 th ) all occurred at times when the London Air Quality Network reported a pollution episode for PM 10. The pollution episodes were due to light easterly winds bringing secondary PM 10 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 PM 10 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 PM 2.5 Table 3-11 shows that there were no exceedances of the provisional UK Air Quality objective concentration for annual mean PM 2.5 at any of the monitoring sites in High data capture rates (i.e. above 90%) for PM 2.5 were achieved at the M25, M4 and M60 motorway sites. Table 3-11: Compliance with Provisional UK Air Quality objectives, particulate matter (PM 2.5 ) Statistic Objective concentration Permitted number of exceedances Measurement method M25 M4 M60 Annual mean 25 g/m 3 n/a TEOM hour mean Calibrated data capture (% of calendar year) n/a n/a TRL 20 RPN744 (I)

27 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/m 3 in England and Wales) was achieved at both the M25 site and the M60 sites in 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 11 th 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/m 3 n/a 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/m 3 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 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/m 3 n/a Calibrated data capture (% of calendar year) n/a n/a * * 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 TRL 21 RPN744 (I)

28 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/m 3. Concentrations of other heavy metals which are not covered by the UK Air Quality Regulations are discussed in section 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 Table 3-14: Compliance with UK Air Quality objectives, lead Statistic Objective concentration Permitted number of exceedances M25 Annual mean 0.25 g/m 3 n/a Data capture (% of calendar year) n/a n/a 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 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/m 3 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 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 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 TRL 22 RPN744 (I)

29 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/m 3 n/a Data capture (% of calendar year) n/a n/a 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 mg/m 3 for formaldehyde and less than 90 mg/m 3 for acetaldehyde 6. The monitoring of aldehydes at the M25 and M60 sites was stopped on 2 nd 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 Concentrations were well below the recommended guidelines at both sites during 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/m 3 Annual mean (mg/m 3 ) Formaldehyde mg/m 3 Annual mean (mg/m 3 ) Aldehydes n/a Data capture (% of calendar year) 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 (based on 1990 emissions estimates). Concentrations of total hydrocarbons (THC) and methane (CH 4 ) 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 TRL 23 RPN744 (I)

30 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 CH 4 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 (CH 4 ) Statistic M25 M60 Annual mean (µg/m 3 ) Calibrated data capture (% of calendar year) Ammonia Ammonia (NH 3 ) 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/m 3 as an annual average 7. 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 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/m 3 in 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 TRL 24 RPN744 (I)

31 Table 3-18: M25 Annual mean concentration, ammonia (NH 3 ) Site Environmental Assessment Level (EAL) annual mean µg/m 3 Annual mean (µg/m 3 ) Data capture (% of calendar year) Distance from hard shoulder (m) Grid reference (OS) Sample tube height (m) Roadside tube average (µg/m 3 ) m , m Background tube average (µg/m 3 ) m , m Table 3-19: M4 Annual mean concentration, ammonia (NH 3 ) Site Environmental Assessment Level (EAL) annual mean µg/m 3 Annual mean (µg/m 3 ) Data capture (% of calendar year) Distance from hard shoulder (m) Grid reference (OS) Sample tube height (m) Roadside tube average (µg/m 3 ) m , m Table 3-20 M60 Annual mean concentration, ammonia (NH 3 ) Site Environmental Assessment Level (EAL) annual mean µg/m 3 Annual mean (µg/m 3 ) Data capture (% of calendar year) Distance from hard shoulder (m) Grid reference (OS) Sample tube height (m) Roadside tube average (µg/m 3 ) m , m Inlet tube average (µg/m 3 ) m , m Background tube average (µg/m 3 ) * 39m , m *Monitoring period 7/09/2010 to 31/12/ 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 4 th 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/m 3, 5 ng/m 3 and 20 ng/m 3 for 8 TRL 25 RPN744 (I)

32 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 Cadmium Annual mean (ng/m3) Data capture (% of calendar year) Annual mean (ng/m3) Data capture (% of calendar year) Annual mean (ng/m3) 6 ng/m n/a ng/m n/a ng/m Nickel Data capture (% of calendar year) n/a Hydrogen sulphide Concentrations of hydrogen sulphide (H 2 S) are measured at the M25 and M60 motorway sites. This pollutant is not included in the UK Air Quality Regulations. The Environment Agency 9 recommends a long term EAL of 140 µg/m 3. Annual average concentrations of H 2 S recorded at the Highways Agency roadside monitoring sites in 2010 were well below this value. High data capture rates (i.e. above 90%) for H 2 S were achieved at the M25 site in 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 (H 2 S) Statistic Environmental Assessment Level (EAL) long term µg/m 3 M25 M60 Annual mean (µg/m 3 ) Calibrated data capture (% of calendar year) n/a 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 TRL 26 RPN744 (I)

33 Table 3-23: Annual average daily and hourly traffic flow Statistic M25 M4 M60 Annual average daily traffic flow Annual average vehicles per hour CW ACW EB WB CW 4183 EB 2286 ACW 4192 WB 2264 CW ACW CW 3350 ACW 3309 CW 97 EB 75 CW 92 Data capture (% of calendar year) ACW 98 WB 86 ACW 90 CW: clockwise; ACW: anti-clockwise; EB: Eastbound; WB: Westbound TRL 27 RPN744 (I)

34 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 NO 2 objective concentration of 40 µg/m 3 was exceeded at the M25, M4 and M60 monitoring sites. There were no exceedances of the 1-hour mean NO 2 objective concentration of 200 µg/m 3. Exceedance of the running 8-hour mean O 3 objective of 100 µg/m 3 occurred at the M60 and M4 sites. There were no exceedances of the relevant objectives for SO 2, PM 10, 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 NO 2 annual mean objective and one hour mean objective were both exceeded which provides an indicative result for the expected results for 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 PM 2.5 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 NH 3 or H 2 S reported at the Highways Agency monitoring sites in There were no exceedances of target values for heavy metals (arsenic, cadmium and nickel) recorded at the M25 site There were no exceedances of the COMEAP recommended maximum exposure value for aldehydes (acetaldehyde and formaldehyde) recorded at the Highways Agency sites in TRL 28 RPN744 (I)

35 References Air Quality (England) Regulations Statutory Instrument 2000 No Air Quality (England) (Amendment) Regulations Statutory Instrument No 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/ 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 TRL report UPR SEA/02/05. TRL, Wokingham. Highways Agency (2007). The Highways Agency roadside air pollution monitoring network TRL report PPR 192. TRL, Wokingham. Highways Agency (2008). The Highways Agency roadside air pollution monitoring network TRL report PPR 371. TRL, Wokingham. Highways Agency (2004). The Highways Agency roadside air pollution monitoring network TRL report UPR SE/020/04. TRL, Crowthorne. Highways Agency (2003). The Highways Agency roadside air pollution monitoring network 1992 to TRL report PR SE/742/03. TRL, Crowthorne. Highways Agency (2005). The Highways Agency roadside air pollution monitoring network TRL report UPR SE/145/04. TRL, Wokingham. Highways Agency (2010). The Highways Agency roadside air pollution monitoring network 2008 Volume II. TRL report RPN 744. TRL, Wokingham. WHO (2000). Air quality guidelines for Europe, 2 nd edition. World Health Organisation Regional Publications, No. 91. WHO. TRL 29 RPN744 (I)

36 Appendix A Figures and locations of monitoring sites A.1 M4 (Theale 2), Pinglewood A.1.1 Ordnance Survey map N M4 Theale 2 Crown copyright. All rights reserved. License No. AL TRL 30 RPN744 (I)

37 A.1.2 Site photos A M4 monitoring station A Selection of instruments inside the M4 monitoring station TRL 31 RPN744 (I)

38 A.2 M25, Bell Common Tunnel A.2.1 Ordnance Survey map N Bell Common Tunnel Crown copyright. All rights reserved. License No. AL TRL 32 RPN744 (I)

39 A.2.2 Site photos A Bell Common Tunnel monitoring station A Selection of instruments inside the Bell Common Tunnel monitoring station TRL 33 RPN744 (I)

40 A.3 M25 (M25B), Staines A.3.1 Ordnance Survey map N M25B Crown copyright. All rights reserved. License No. AL TRL 34 RPN744 (I)

41 A.3.2 Site photos A M25 monitoring station A Selection of instruments inside the M25 monitoring station TRL 35 RPN744 (I)

42 A.4 M60, Kirkhams A.4.1 Ordnance Survey map N M60 Crown copyright. All rights reserved. License No. AL TRL 36 RPN744 (I)

43 A.4.2 Site photos A M60 monitoring station A Selection of instruments inside the M60 monitoring station TRL 37 RPN744 (I)