Air Quality
7.8 Air quality in the South West is generally good with low levels of sulphur, nitrogen dioxide and particulates in comparison to the rest of England. However, pockets of poor air quality exist in the region, especially within large urban industrial areas such as Bristol.
7.9 If a Local Authority finds that national air quality objectives may not be met in a specific area, it must declare an Air Quality Management Area (AQMA) and develop a plan to improve air quality within the designated area. 28 AQMAs have been established by 18 local authorities in the region, this figure is not necessarily comparible to previous years due to the amalgamation of 5 separate AQMAs into one in both Exeter City and Salisbury. These AQMAs are primarily in urban areas and 92% (26) are a result of traffic emissions (National Environmental Technology Centre, 2008).
7.10 Nationally, in 2006 there was an average of 41 days of moderate or higher air pollution in urban areas (up from 22 days in 2005) and 57 days in rural areas (up from 40 days in 2005) (Netcen and Defra, 2007).
7.11 It is not possible to provide regional averages because there are too few sites in some regions. Instead, Plymouth Centre and Bristol Centre have been chosen as representative urban sites in the region, whilst Yarner Wood (Devon) and Somerton (Somerset) are representative rural sites.
7.12 Data was not available for Bristol City and Plymouth City in 2006. However, monitoring at the two rural sites in the region revealed that Yarner Wood experienced 73 days of moderate or higher air pollution (up from 35 in 2005) whilst Somerton had 43 (up from 34 in 2005).
7.13 The average number of days with moderate or higher air pollution has generally decreased significantly in urban areas since 1993, largely because of a reduction in particles and sulphur dioxide. In rural areas, where ozone is the main cause of pollution, there has been no overall trend.
7.14 From year to year there can be significant variations caused by the weather, particularly for ozone, more of which is created in hot sunny weather. For example, the hot summer of 2003 was a major factor in the high figures for that year.
7.15 Rural air quality is influenced by ground level ozone, levels of which are naturally high in the South West due to the close proximity to the coast and high altitudes. High levels of ground level ozone can be detrimental to health, causing irritation of eyes, nose and lungs. As a result, Defra's provisional health objective is that the daily maximum 8 hour running mean should not exceed a concentration of 50 parts per billion on more than 10 days a year at any site by 2005. There has been no clear trend in the average annual concentration of ground level ozone over the last 20 years both nationally. The 6 Monitoring sites in the South West also show no clear trend, however, all showed a significant decline between 2003 and 2005 and an increase between 2005 and 2006. (Netcen and Defra, 2007)
7.16 Full information about air quality in the South West is available from the South West Observatory Environment website. Air quality, local air quality, car use, traffic growth and alternative fuels are also indicators used to monitor progress of the Regional Environment Strategy.