9.2 Background

9.2.1 Existing Air Quality in Lancashire

Sources of pollution fall into three categories; mobile, point and stationary. Mobile sources include all modes of transport. Point sources include large and small industrial processes. Stationary sources include combustion of fuels for domestic and commercial purposes. Of all the emission categories, road traffic is currently the dominant source in Lancashire for certain pollutants, with nitrogen dioxide contributing most to overall emissions.

Using the National Atmospheric Emissions Inventory current data set (2003) it has been possible to produce emission maps for Lancashire. The data can be sub divided by pollutant and source. Results are available on a 1x1km grid. Nitrogen dioxide and particulates pollution are detailed in both map and table form below.

A simple assessment of this information indicates that road traffic in Chorley accounts for 84% of the total Nitrogen Dioxide emitted in the district with the motorway network being the dominant source. In contrast, whilst Ribble Valley produces the greatest amount of Nitrogen Dioxide of any district in Lancashire, the contribution from road transport is small at 19%.

9.2.2 Air Quality in Lancashire

Estimated Nitrogen Oxides as NO₂

The following maps display the estimated Oxides of Nitrogen. Total emissions from all sources are compared to the road transport component. Road transport is the biggest contributor to Oxides of Nitrogen pollution in Lancashire, with the flows on the motorway network being the worst source.

Figure 9.2.2a Total Nitrogen Dioxide                          Figure 9.2.2b Road Transport Nitrogen Dioxide

Estimated Particulate PM10

The following maps display the estimated PM10 emission. Again, total emissions from all sources are compared to the road transport component. As can be seen, the road network is only a small contributor to the total level of particulates emitted in Lancashire.

Figure 9.2.2c Total Particulates (PM10)                   Figure 9.2.2d Road Transport Particulate (PM10)