Technical note - PSA target 6

Improve air quality by meeting the Air Quality Strategy targets for carbon monoxide, lead, nitrogen dioxide, particles, sulphur dioxide, benzene and 1,3 butadiene. Joint with Defra.

Technical Note status: Unchanged

The UK Air Quality Strategy sets different dates for achieving health-based targets for each air pollutant between 2003 and 2010. The targets are expressed in terms of the desired concentrations of individual pollutants in air (generally measured as the number of microgrammes of each pollutant per cubic metre of ambient air) to be achieved by a fixed date. A summary of what the Air Quality PSA commits the Government to meeting in England is set out in the table below:

PSA Air Quality Objectives and Target Dates

Pollutant	PSA Air Quality Strategy objectives in England for protection of public health		Date to be achieved by
	Concentration	Measured as
Benzene	16.25 micrograms/m3	running annual mean	31.12.2003
Benzene	5 micrograms/m3	annual mean	31.12.2010
1,3 -butadiene	2.25 micrograms/m3	running annual mean	31.12.2003
Carbon monoxide	10 mg/m3	daily maximum running 8-hour mean	31.12.2003
Lead	0.25 micrograms/m3	annual mean	31.12.2008
	0.5 micrograms/m3	annual mean	31.12.2004
Nitrogen dioxide*	200 micrograms/m3 not to be exceeded more than 18 times a year	1 hour mean	31.12.2005
	40 micrograms/m3	annual mean	31.12.2005
Particles (PM10) (gravimetric) all of England	50 micrograms/m3 not to be exceeded more than 35 times a year	24 hour mean	31.12.2004
	40 micrograms/m3	annual mean	31.12.2004
Particles (PM10) * (gravimetric) all of England except London	50 micrograms/m3 not to be exceeded more than 7 times a year	24 hour mean	31.12.2010
	20 micrograms/m3	annual mean	31.12.2010
Particles (PM10) * (gravimetric) London only	50 micrograms/m3 not to be exceeded more than 10 times a year	24 hour mean	31.12.2010
	23 micrograms/m3	annual mean	31.12.2010
Sulphur dioxide	350 micrograms/m3 not to be exceeded more than 24 times a year	1 hour mean	31.12.2004
	125 micrograms/m3 not to be exceeded more than 3 times a year	24 hour mean	31.12.2004
	266 micrograms/m3 not to be exceeded more than 35 times a year	15 minute mean	31.12.2005

* Provisional objectives that might need to be revised following the review of corresponding EU Directive limit values in 2004/5 by the European Commission.

The full details are at

http://www.defra.gov.uk/environment/airquality/index.htm

Performance, in terms of progress towards the targets, is assessed annually by means of data from the national air quality monitoring network and published on Defra's website and in Defra Annual Report, available on the website at: http://www.defra.gov.uk/environment/index.htm.

Monitoring data from sites in the Government's Automated Urban and Rural Network (AURN) are published on Defra's website in real time. Quality Control and Quality Assurance processes are then carried out every 6 months. In order to assess whether an annual objective has been met, it is necessary to wait until the end of the 12 month calendar year plus the 6 month Quality Control and Quality Assurance period. An objective to be met by the end of 2010, for example, would be formally assessed by the second half of 2011.

The level of accuracy sought for the data must meet mandatory monitoring and modelling requirements in European air quality directives ¹ . Accuracy and precision have been calculated for each pollutant in the UK national monitoring network. This gives an accuracy range of between 8% to 11%, which is well within the uncertainties provided by the EU air quality directives. Data uncertainties will be recalculated in the light of guidance from the European Standards Institute (CEN), expected in the near future. In addition to the annual assessment of measured concentrations, a general assessment of progress in improving air quality is published each year against the air quality headline indicator H10 for sustainable development, which records days when air pollution is moderate or higher. Details available at:

www.sustainable-development.gov.uk

The public can obtain regularly updated information about air quality in their area, and regional forecasts and health advice through Defra's freephone service on 0800 556677, on TV, ceefax and teletext and via the internet: www.airquality.co.uk.

¹ Directives 1996/62/EC, 1999/30 EC, 2000/69EC.