Air quality indicator for sustainable development 2009 - Final Results Now Available

News published: 06/05/2010

The air quality indicator is one of the 68 indicators of the Government's Sustainable Development Strategy. It measures annual levels of pollution from particulates (PM10) and ozone (O3), the two pollutants thought to have the greatest health impacts, as well as the number of days on which levels of any one of a basket of five pollutants were "moderate or higher".

These results are an update of those published on 28 January following the full quality control (ratification) process. The differences are minimal, the largest being a decrease in the average number of days of moderate or higher pollution at urban sites from 12 to 10 days.

  • 2009 has seen a general improvement in monitored air quality compared to 2008.
  • Urban background particulate levels averaged 19 micrograms per cubic metre (µg m-3) in 2009, unchanged from 2008. These levels have fluctuated, but there has been an overall decreasing trend since 1993, the first year for which data were available.
  • Roadside particulate levels averaged 22 µg m-3 in 2009, compared to 26 µg m-3 in 2008. Again, there has been a general downward trend since the series began in 1997.
  • Urban background ozone* levels averaged 55 µg m-3 in 2009 compared to 59 µg m-3 in 2008 and 44 µg m-3 in 1992, the first available data. These levels had shown an overall increasing trend since 1992, but this has shown signs of levelling out in recent years.
  • Rural ozone levels* averaged 68 µg m-3 in 2009, compared to 71 µg m-3 in 2008 and 59 µg m-3 in 1987, the first available data. There is no clear long term trend.
  • In urban areas, air pollution in 2009 was recorded as moderate or higher on 10 days on average per site, compared with 26 days in 2008, and 59 days in 1993. This series has shown a high degree of year-on-year variability and there is no clear long term trend.
  • In rural areas, air pollution in 2009 was moderate or higher for 32 days on average per site, compared with 45 days in 2008 and 21 days in 1987. This series has also fluctuated significantly over time, with no long term trend.

* Measured as the daily maximum 8-hour running mean

The full report is available for download, archived at

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