A blanket of air

Dr Richard Maggs, Stanger Science and Environment, highlights the proposals to increase the extent and coverage of air quality monitoring in the UK in response to EU drivers.

The Government White paper on the Environment, This Common Inheritance, published in 1990, committed the UK Government to a major expansion of urban air quality monitoring.

After its publication, the first phase of the Government’s Enhanced Urban Monitoring Initiative led to the establishment of automatic urban background monitoring stations in London, Cardiff, Edinburgh, Birmingham, Newcastle and Belfast, providing information on O3, NOx, CO, SO2 and PM10. Since then, an additional six sites have been established in Hull, Leeds, Liverpool, Bristol, Leicester and Southampton: the start of what we see as the current backbone of the automatic network, was put into place.

In the second phase of enhancement, continuous monitoring stations measuring hydrocarbon species were established in Central and Greater London, Cardiff, Belfast, Birmingham, Edinburgh, Bristol and Middlesbrough. Urban air quality, however, is not the only interest. The occurrence of photochemical pollution too across the UK is one of concern; one to which Government has had to respond. Under Council Directive 92/72/EEC, guidelines for Member States were introduced for the monitoring and reporting of ozone episodes. The majority of the Rural Network was established in 1986/1987, although sites at Sibton, Harwell and Bottesford had previously been reporting ozone figures since the mid-1970s.

Under the EC Framework Directive on Ambient Air Quality (Council Directive 96/62/EC, issued in 1996), further expansion of the network has continued, culminating in 1998 with the formation of the Automatic Urban and Rural Network (AURN). Formed of the separate urban and rural networks, the AURN, alongside the London Air Quality Network (LAQN) and Hydrocarbon Network, takes the total number of automatic monitoring stations in the UK to 108.

Further expansion of the network is set to continue in order for the UK to meet the requirements of the Ambient Air Quality Directive and subsequent Daughter Directives for air quality under EU legislation. It is anticipated that four new urban and two new rural DETR-owned sites will be commissioned during the year 2000.

In addition to the commissioning of centrally funded automatic monitoring stations, currently within the automatic network there are 37 affiliated local authority monitoring stations. Initial estimates to fulfill the first Daughter Directive (Council Directive 1999/30/EC) indicate that a further 15 such sites will be required to be affiliated into the network this year.

The operational structure of the automatic networks is one of decentralisation. Main functions are managed by three separate units: the Central Management and Co-ordination Unit (CMCU); the Data Dissemination Unit (DDU); and the Quality Assurance and Quality Control Unit (QA/QC). Stanger Science and Environment has maintained the role of CMCU for the AURN for the last eight years. QA/QC is currently undertaken by the National Physical Laboratory (NPL) for the rural monitoring stations whilst the National Environment Technology Centre (NETCEN) undertakes this role for the urban monitoring stations and those included in the LAQN, for which the South East Institute of Public Health (SEIPH) undertakes the role of CMCU.

In a unique data dissemination system comparable to no other, measurements of air quality across the UK are collected via modem telephone links, processed,

and released as hourly averages via the Department’s Air

Quality Information Archive, www.aeat.co.uk/netcen/airqual. This feeds information to the public via CEEFAX, TELETEXT, television and radio weather forecasts, and newspapers. In a drive to improve its public dissemination of information, the Government now reports statistics for a number of pollutants directly comparable with the objectives set in the Air Quality Strategy. Further, the recent addition of the Site Information Archive (www.stanger.co.uk) provides information relevant to site location, classification and local geography. Uniquely within Europe, this makes for a network where any member of the public can obtain up-to-date (almost real-time) data and information regarding air quality in any part of the UK.

In the last few years, it has been the issue of particulate pollution (PM10 and PM2.5) that has been the basis of improvements to the network. Increasing concern surrounding the health effects of particulate pollution, its complex chemical nature and long-range transportation has put particulate pollution on the “A-list” of pollutants. In 1999, the Government’s Airborne Particles Expert Group (APEG) published its report, which greatly increased the scientific understanding and source apportionment of particle pollution in the UK. Not least, the identification and significance of the secondary component from mainland Europe and its overall contribution to the PM10 fraction.

In response to these concerns and EU legislation requirements surrounding the harmonisation of measurement techniques, the Government has sought to establish a number of particulate “super-sites”. In particular, sequential gravimetric samplers for PM10 and PM2.5 have been installed, alongside condensation particle counters. Covering a wide array of site classifications (e.g. kerbside, industrial background, urban background and rural), the information produced will compliment existing research programmes sponsored by the DETR, the Medical Research Council and the Department of Health, utilising information on demographics for each of the main UK urban areas: London, Birmingham and Manchester. Moreover, proposals to increase the capability of the network to include chemical speciation of particulate pollution (carbon – elemental and organic, metals, sulphate and nitrate) will prove invaluable in determining the likely contributing factors to health effects observed by epidemiologists.

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