Air quality

Summary of emissions data per sq km for nitrogen oxides, particulates and sulphur dioxide

We have analysed the local 2019 emissions data per square kilometre for nitrogen oxides, particulates and sulphur dioxide.  These have been sourced from the National Atmospheric Emissions Inventory. Nitrogen oxides are greenhouse gases that contribute to acid rain, depletion of the ozone layer and have detrimental effects on health. High emission levels in the county are associated with urban areas and the main road networks. Particularly high local area emissions are not surprisingly found at locations of major industrial activity in the county. 

It is important to note that high levels of local emissions cannot be directly equated with local air quality at ground level. The height of an industrial chimney will be specifically regulated for the industrial processes being carried out, and the emissions will be dispersed away from the plant depending on meteorological conditions. Emissions from traffic tend to have a more direct impact on air quality at ground level.

Particulate matter refers to tiny particles suspended in the air. They include not only smoke and dust particles, but also mould and other spores and pollen. Particulates may affect the heart and lungs, and are often seen as one of the most critical of pollutants as a result of their impact on human health.  Emissions of PM2.5s have fallen by 54% since 1990 but PM2.5s still need to be reduced by a further 18% to meet the 2020 Gothenburg Protocol target

For the 2018 data we have analysed the separate sources of emissions from 11 sectors, and looked in particular at the road transport data. Maps of the total emissions for the three pollutants are available as appendices: Appendix 1: Oxides of Nitrogen, Appendix 2: Particulate matter PM2.5 (Particulates <2.5 µm) and Appendix 3: Sulphur dioxide. We have also calculated total and average emission values for all 14 Lancashire authorities, together with the percentage of NOx and particulate emissions attributable to road transport sources. This is displayed in the Microsoft Power BI slide below (which can be expanded to full-screen by clicking the double-headed diagonal arrow on the right of the grey footer bar) and is available as a Microsoft Excel download at the foot of the page. A second slide has been added with all emissions exceeding one tonne per square km or from major point sources which exceed one tonne per annum. 

The key findings are:

  • Hanson Cement near Clitheroe in Ribble Valley was identified as the source of 884 tonnes of NOx, 128 tonnes of sulphur dioxide and 17.9 tonnes of particulate matter
  • Nearly all of the motorways in Lancashire were responsible for levels of NOx that were in the highest 5% of grid squares for NOx attributed to road transport in the UK
  • In South Ribble just under 500 tonnes of NOx, 23 tonnes of SO2 and 19 tonnes of particulate matter were generated in Leyland from industrial sources
  • 690 tonnes of NOx were generated by motorway traffic in Chorley district
  • The motorways in South Ribble were sources for 255 tonnes of NOx and high levels of particulate emissions (8 tonnes)
  • The motorways in Preston were sources for 446 tonnes of NOx and high levels of particulate emissions
  • Heysham Port was the source of over 160 tonnes of NOx
  • Warton Aerodrome is identified as a source for over 100 tonnes of NOx and around 11 tonnes of particulate matter
  • Chemical and waste processing works on the Wyre estuary produced nearly 120 tonnes of NOx and 41 tonnes of sulphur dioxide. 

The full report on emissions is in the 'Further analysis' panel at the foot of the page

Concentrations of air pollution - DEFRA interactive map

An additional source, providing a complementary indication to emissions of pollution, is the Department for Environment, Food and Rural Affairs UK Ambient Air Quality Interactive Map, which shows some of the most common pollutants which are also seen in the NAEI emissions maps but as average concentrations rather than tonnage emitted. Each pollutant is shown in background or roadside concentrations. This data is available for years up to 2017. Urban area and local authority boundaries can be overlaid in this facility as can the Air Quality Management Area boundaries in which Nitrogen dioxide is monitored - see the accompanying Lancashire Insight article on air quality monitoring.

Summary of air quality results from the 2019 indices of deprivation

A combined indicator of air quality for small local areas was developed as part of the English Indices of Deprivation and the results are available for the 941 lower super output area level (LSOAs) in the Lancashire-14 area. Scores of below 1 are regarded as 'safe' concentrations of any of the four pollutants: NOx, SO2, particulates and benzene. Many urban areas in Lancashire suffer to some degree from poorer air quality than other parts of the county though it is much less of an issue in the coastal towns.

Much of Lytham St. Annes, Bolton-le-Sands, Hest Bank, Garstang and Preesall are in the lowest scoring band while much of St Annes, Burscough, Bacup, Kirkham, Poulton-le-Fylde, Longridge and Clitheroe are in the second. No parts of Blackburn, Lancaster, Blackpool and only one LSOA in Skelmersdale have an indicator score exceeding 1.

Most Lancashire areas recorded good overall air quality results. A total of 51, just 5.4%, of the 941 LSOAs in the Lancashire-14 area recorded a combined air quality result in excess of 1.00. The highest recorded score in Lancashire (1.09), which occurs in four adjoining LSOAs in Preston and a single one in Hyndburn (002C), is significantly below the worst level recorded in the country (1.9). No areas of Lancashire experience air pollution levels anything like those recorded in the centres of London and other larger cities. The combined air quality Indicator reveals that out of 32,845 LSOAs in England, the worst performing Lancashire LSOAs were in 8,641st position. 

The LSOA in Hyndburn mentioned above (002C) is located at the southern end of Altham ward between Church and Clayton-le Moors. It straddles the M65 motorway, being just east of Junction 7. It is close to, or actually covers part of, the Whinney Hill Quarry, which is responsible for major emissions of NOx. This LSOA no longer adjoins others scoring over 1, although there are a couple more in the Accrington area. The equally ranked Preston LSOAs cluster around an area in Ashton on Ribble and Tulketh where the West Coast Main Line and the Blackpool railway line diverge, and which is bounded on the north side by the A5085 Blackpool Road.

Other areas with an indicator score over 1 lie within the built up areas of Preston, Bamber Bridge, Leyland, Chorley, Burnley, Pendle and Haslingden. In Pendle the whole of Whitefield and Walverden wards in Nelson score over 1, and this contributes towards Whitefield being ranked the most deprived ward in England for the living environment sub-domain, of which air quality forms a significant part.

Page updated September 2021