Poor local air quality is the result of pollutants such as dust and fine particulates, ozone and carbon monoxide building up in towns and cities. The consequences include smog and health problems for those with breathing problems such as the young, older people and asthma sufferers. While power stations and other industrial sites can contribute to poor local air quality, the main source tends to be traffic. The wider-reaching effects of air pollution also include acid rain resulting from emissions of sulphur dioxide and nitrogen oxides.

All existing coal-fired sites in the UK now have to comply with the European Union's (EU's) Large Combustion Plants Directive (LCPD), which seeks to reduce emissions of sulphur dioxide (SO₂), nitrogen oxides (NOx) and dust particulates from large-scale industrial works such as power stations, refineries and steelworks. We will be giving our Ratcliffe power station the investment it needs to maintain long-term security of supply, but we have decided not to do the same at Ironbridge and Kingsnorth, which means that they will run at restricted output levels after 2008, ahead of closure by 2015. Any new coal-fired stations we develop will be built with LCPD requirements in mind and will emit significantly lower levels of pollutants than the generation of plants they replace.

SO₂ emissions from Generation, kt

2004	2005	2006
76	67	62

This graph reflects the use of coal-fired power stations to produce electricity. The continued burning of lower-sulphur coal at Ironbridge and lower generation output from Ratcliffe-on-Soar meant that our total emissions of SO₂ continued to reduce.

SO₂ emissions per TWh, kt/TWh

2004	2005	2006
1.72	1.65	1.62

This graph reflects the number of coal-fired power stations operating within our generation portfolio, the type of coal burnt and the level of SO₂ abatement these power stations have.

NOx emissions from Generation, kt

2002	2003	2004	2005	2006
44.7	62.7	55.1	57.2	57.6

This graph reflects the use of fossil fuel fired electricity generation. The slight increase in NOx emissions in 2006 is a result of greater output from Kingsnorth, which has a marginally higher NOx intensity than Ratcliffe-on-Soar. The output was reduced in 2006 due to an unplanned outage.

NOx emissions per TWh, kt/TWh

2002	2003	2004	2005	2006
1.06	1.31	1.24	1.42	1.52

This graph reflects the use of fossil fuel-based generation and choice of fuels used to produce electricity. The slight increase in NOx intensity in 2006 is a result of greater output from Kingsnorth, which has a marginally higher NOx intensity than Ratcliffe-on-Soar whose output was reduced in 2006 due to an unplanned outage.

Particulate emissions from Generation, kt

2002	2003	2004	2005	2006
0.46	0.75	0.58	0.84	1.02

particulate matter smaller than 10 microns diameter

This graph reflects the use of fossil fuel-fired power stations to produce electricity. The increase shown is reflective of the inclusion of data from a greater number of gas-fired stations and more intermittent operation in response to planned and unplanned outages and variations in demand and supply, notably the unplanned outage at Ratcliffe, which meant that our other coal-fired stations ran for longer to compensate.

Particulate emissions per TWh, kt/TWh

2002	2003	2004	2005	2006
0.011	0.016	0.013	0.021	0.027

particulate matter smaller than 10 microns diameter

This graph reflects the number of coal-fired power stations operating within our generation portfolio and the level of particulate abatement or 'filtering' these power stations have.

The burning of fossil fuels, particularly coal, also results in emissions of a number of trace elements. Further details of these are available here.

Details of our emissions of greenhouse gases are included here.

Further details of the environmental performance of each our sites are available here and detailed environmental trend data going back to 1990 is available here.