Air quality

Summary of Review of Significant Sources of Pollution

Information about air quality in solihull

2 Summary of Review of Significant Sources of Pollution

The Department of Environment, Transport and the Regions have defined "significant sources" of air pollution as heavily trafficked or congested roads, industrial processes, which are authorised under the Environmental Protection Act 1990, and combustion plant with a thermal energy rating of more than 3 MW.

The following sections describe the significant sources of prescribed air pollutants for Solihull. A series of maps are also provided which show the geographical distribution of the listed sources:

• Map 1 showing the roads with flows of more than 80000 vehicles per 24 hours: classed as significant sources of carbon monoxide, fine particles (PM₁₀) and nitrogen dioxide;
• Map 2 showing the roads with flows of more than 15000 vehicles per 24 hours: classed as significant sources of nitrogen dioxide and fine particles (PM₁₀);
• Map 3 showing the premises authorised under the Environmental Protection Act, Part 1A for integrated pollution control (IPC);
• Map 4 showing the premises authorised under the Environmental Protection Act, Part 1B for local air pollution control (LAPC);
• Map 5 showing the petrol stations selling more than 1000 m³ petrol per annum authorised under the Environmental Protection Act, Part 1B for local air pollution control (LAPC).

The following subsections contain details of how the data was acquired, processed and any assumptions that were made.

Road Sources

The data on traffic flows is modelled data supplied by the West Midlands Joint Data Team. It is similar to that provided in the West Midlands Atmospheric Emissions Inventory produced by the London Research Centre in 1996. However, the data was remodelled in 1998 to take into account three new major road projects, one each in Birmingham, the Black Country and Coventry. It is recognised that there were a number of assumptions and inaccuracies in the data provided, but where possible, the data has been adjusted to match actual traffic counts. In addition:

• The West Midlands road network has been split into around 3000 road links, a link being a stretch of road that ends either at a road junction or at a geographical or political boundary. In either case, a further link or several links will radiate from that end point. The end points or nodes of the links are defined with an accuracy of only a 100m in both the easting and northing grid references. Some of the links, particularly in town centres and other heavily built up areas with lots of road junctions, are quite short and so were difficult to describe in terms of their precise start and end points due to this low accuracy. A considerable effort has been expended to define more accurate grid references, for those roads, which have a significant potential to pollute,
• Some roads in town centres have been pedestrianised or have had their traffic regimes changed. On some, the traffic flows have been reassigned to surrounding roads, but for others the traffic flows have not yet been adjusted.
• The only important road development, which might affect Solihull, is the construction of the Birmingham Northern Relief Road. This motorway will run across the north-eastern edge of the conurbation, from the M6 at Junction 4 to the M6, near Junction 11. Construction is due to commence in 2001 and the motorway should be completed in 2004. Although for much of its length outside the West Midlands conurbation, it is expected to reduce the volume of traffic on the M6, junctions 4 to 12, but might induce higher traffic flows on the M42, junctions 3 to 9.

The road data was received in Excel spreadsheets, with each record containing information on grid reference, link length, peak hour flows, traffic speed. The average daily traffic flow was calculated by multiplying the peak hourly flows by a factor of twelve. The DETR's revised pollutant specific guidance (LAQM.TG4(00)) provides guidance on how to calculate the traffic volume thresholds above which the emission of a particular pollutant are considered to be a significant in public health terms. For Solihull, the calculations indicate that the thresholds are; 15000 vehicles per day for nitrogen dioxide, 15000 vehicles per day for PM₁₀ particles and 80000 vehicles per day for carbon monoxide. All the links, which met these criteria were plotted on an Arcview GIS system and laid over a digital Ordnance Survey street map of the West Midlands. Each link was then carefully defined with its road name, and/or road number and a description of its starting and finishing points.

The road links are presented in two maps, one for the 80000 vehicles per day traffic flow threshold, and the other for the 15000 vehicles per day threshold.

Industrial Processes Authorised Under IPC

The Environment Agency is responsible for authorising, and periodically inspecting, all processes authorised under the Environmental Protection Act 1990 (Part 1A).

For the "Stage 1" Review of Significant Sources of Pollution, the Environment Agency supplied the West Midlands Joint Pollution Group with a full list of the processes, authorised for Integrated Pollution Control (IPC), in 1999. The information was supplied on a Microsoft Access database. The precise locations of the processes were identified using an Arcview GIS system, and then plotted to show the locations of all the processes within Solihull (see map 3).

Then, for this "Stage 3" Assessment of the Effects of Pollution, more detailed information was collected on emissions and pollutant release conditions. This information was needed to model the effects of the emissions from these processes. Some of the information was collected from the Environment Agency's Pollution Index, which is available on their web site. But most of the information related to the pollutant release conditions was obtained from the public registers, held by Solihull Council, which included data on pollutant emissions as recorded in the most recent Inventory of Sources and Releases (ISR (98)) returns, filed in the same public registers.

Industrial Processes Authorised Under LAPC

Local Authorities are responsible for authorising, and periodically inspecting, all processes authorised under the Environmental Protection Act 1990 (Part 1B).

For the "Stage 1" Review of Significant Sources of Pollution, Solihull Council updated the list of processes, currently operating within its area, and authorised under Local Air Pollution Control (LAPC).

The Environmental Health staff checked their register to compile a list of names, addresses and grid references of all the processes authorised in 1999. This list updated the original information, compiled for the West Midlands Atmospheric Emissions Inventory, and published in 1996.

Solihull Council has a number of authorised processes, which were not thought to emit significant amounts of any of the pollutants under review and the work of gathering information on emissions rates and pollutant release conditions, for all these processes, was felt to be rather onerous.

So, for this "Stage 3" Assessment of Pollution Effects, the processes were ranked according to advice in Appendix 3 of the "Pollutant Specific Guidance" (LAQM.TG4 (00)). The Environmental Health staff then concentrated on gathering information on the emissions rates and pollutant release conditions, from those processes identified in the "guidance". Processes not identified as significant emitters, for this assessment, may still be considered in greater depth the next Review and Assessment, to be carried out by 2003.

To assist in gathering the information, a questionnaire was prepared, which set out the information to be checked or collected in a structured way. Once filled in, the information on the forms could be quickly and efficiently transferred to a Microsoft Access database. The updated information was then re-issued to the Pollution Control officers, to be retained as a resource for their use, and to be updated during subsequent inspections of the processes.

The locations of the processes were checked on an Arcview GIS system, and then plotted to show the locations of all the processes within the Borough (see map 4).

Petrol Stations Authorised Under LAPC

In 1998, one more group of processes was added to the list of processes authorised under the Environmental Protection Act 1990 (Part 1B). Local authorities became responsible for authorising and periodically inspecting all petrol stations, which sell more than 1000 m³ of petrol per annum.

Although listed separately for convenience, these petrol stations are authorised and inspected like any other LAPC process.

The locations of the processes were checked on an Arcview GIS system, and then plotted to show the locations of all the processes within the Borough (see map 5).

Modelling

All the relevant data was input to a model which used INDIC Airviro software. The model is a complete air quality management system which includes the following functional blocks:

• emission surveying and modelling
• dispersion modelling
• monitoring data collection, analysis and presentation

The model overlays all the different categories of information, such as windspeed, topography, traffic data, data on industrial processes, and is then run to find out the effects of all these acting together.

The modelling for all seven West Midlands metropolitan authorities was carried out on one computer based at Birmingham City Council's offices.

MAP 1 - Roads with 80000+ vehicles per day

MAP 2 - Roads with 15000+ vehicles per day

MAP 3 - Processes Authorised under IIPC

MAP 4 - Processes authorised Under LAPC

MAP 5 - Authorised Petrol Stations

Note: only those petrol stations selling more than 1 million litres (1000 metres³) of fuel are required to be authorised.

Birmingham International Airport

The effect of Birmingham International Airport on air quality in Solihull has been considered. The Airport operates an air quality monitoring station which is located on the airfield. Data from this station has been collected since 1995, and are included in graphs in this report. Since 1994 the Airport have commissioned a biennial nitrogen dioxide survey using diffusion tubes which is carried out over 13 weeks during the summer period. The survey is designed to investigate the spatial effects of pollutants arising from the Airport site, and has shown that the main ground level effect of emissions from the Airport occurs at the Airport itself, and primarily on the main access roads within the Airport. Diffusion tube monitoring sites are located at the airfield, in Solihull MBC's area and in Birmingham City Council's area. Results indicate that nitrogen dioxide (and by implication other airborne pollutants) from the airfield is dispersed and does not show an effect further afield, and therefore should not affect sensitive receptors living nearby (see Figure 2.1) The Airport also commissioned a GIS (Geographical Information System) referenced emissions inventory for the site based on the year 1997. Due to time constraints these data were not included in our modelling, but will be taken into account during the next review and assessment. The public road network around the Airport has been included in the modelling, as were data on emissions from aviation which were included in the London Research Council's West Midlands Emission Inventory (1996).

FIGURE 2.1 - Mean values of NO2 diffusion tube sites