Air quality

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

We have analysed the local 2016 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 concentrations 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 17% to meet the 2020 Gothenburg Protocol target

For the 2016 data we have analysed the separate sources of emissions from 11 sectors, and looked in particular at the road transport data. The local concentrations of high emissions from a variety of these sectors for both all three pollutants have been combined into a single map.  As a result of this we have not needed as great an extent of analysis into the total emissions of the pollutants as previously. 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.


The key findings are:

  • Hanson Cement near Clitheroe in Ribble Valley was identified as the source of 720 tonnes of NOx, 149 tonnes of sulphur dioxide and 35.1 tonnes of particulate matter
  • Nearly all of the motorways in Lancashire were responsible for levels of NOx that were in the highest 5% of NOx attributed to road transport in the UK
  • In South Ribble over 500 tonnes of NOx and 21 tonnes of particulate matter was generated in Leyland from industrial sources
  • Over 700 tonnes of NOx were generated by motorway traffic in Chorley district
  • The motorways in South Ribble were sources for over 250 tonnes of NOx and high levels of particulate emissions
  • The motorways in Preston were sources for around 360 tonnes of NOx and high levels of particulate emissions
  • Heysham Port was the source of over 150 tonnes of NOx
  • Warton Aerodrome is identified as a source for over 100 tonnes of NOx and around 10 tonnes of particulate matter
  • Chemical works on the Wyre estuary produced nearly 50 tonnes of sulphur dioxide and 22 tonnes of particulate matter 

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 2015 index of multiple 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. Many urban areas in Lancashire suffer to some degree from poorer air quality than other parts of the county though it is clearly much less of an issue in the coastal towns.

Much of Lytham, Fleetwood, Preesall and Bolton-le-Sands are in the lowest scoring band while much of Blackpool, St Annes, Tarleton and Clitheroe are in the second. With the exception of Clitheroe, these are all near the coast.

Most Lancashire areas recorded good overall air quality results.  In contrast, a total of 20%, 192 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 (1.31 in Hyndburn 002C) is significantly below the worst level recorded in the country (2.301). 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 LSOA was in 4,838th position,  

The LSOA in Hyndburn mentioned above (002C) is located between Church and Clayton-le Moors. It straddles the M65 motorway, being just east of Junction 7. It lies at the centre of a large extent of areas with an indicator score of more than 1. The area takes in most of the towns in Hyndburn also including Rishton, Altham, Oswaldtwistle, parts of Great Harwood and most of Accrington. The area is largely urban, but not exclusively so. The key feature is perhaps that the M65 runs through the middle of it. To the west of Hyndburn the area extends into the built-up urban parts of Blackburn, and continues south into Darwen. To the east of Hyndburn there is a gap where the indicator score falls below 1 into the 2nd band then much of Burnley and Nelson further east along the M65 scores over 1.

Other areas with an indicator score over 1 lie within or adjacent to the built up areas of Preston, Bamber Bridge (in this case extending south to Whittle-le-Woods), Chorley, Skelmersdale, Shevington Vale and Haslingden. The sole LSOA in Fylde with a score above 1(Fylde 007E), that is away from the true urban areas, covers part of the Warton aerodrome. Other high scoring areas may all be on account of busy traffic locations.

Further analysis

Nitrogen oxides, particulate and sulphur dioxide emissions full report (PDF 2.3 MB) 

Total and average Nitrogen oxides, particulate and sulphur dioxide emissions by district (Excel 15 KB)

Air quality results from 2015 index of multiple deprivation full report (PDF 57 KB)

Page updated December 2018