Emissions of greenhouse gases are discussed elsewhere in this report but our power stations also emit other pollutants to the air. The three most significant of these are sulphur dioxide (SO2), oxides of nitrogen (NOx) and particulate matter (or dust).

SO2 and NOx are associated with acid rain and local air quality issues affecting human health and other environmental receptors. Particulate matter is associated with health concerns and can lead to respiratory diseases, most notably in the elderly and vulnerable.

Emissions of all three types of pollutant have decreased sharply since the early 1990s following the introduction of stringent environmental standards and we're constantly working to find ways of reducing them even further. Because emissions from the electricity generation sector and heavy industry have reduced to such an extent, road traffic is now the primary source of local air pollution.

Our power station at Ratcliffe-on-Soar is fitted with flue gas desulphurisation (FGD) technology which means that most of the sulphur is captured by injecting limestone slurry into the flue gases and turning it into gypsum. This means that Ratcliffe can use British coal, which typically has a high sulphur content. Our other two coal power stations at Kingsnorth and Ironbridge do not have FGD fitted and therefore burn lower sulphur coal to keep emissions to a minimum.

Sulphur Dioxide Emissions per TWh (kilotonnes per TWh)

2004	2005	2006	2007
1.72	1.65	1.62	1.33

Oxides of Nitrogen (NOx) per TWh (kiltonnes/TWh)

2003	2004	2005	2006	2007
1.31	1.24	1.42	1.52	1.4

Our NOx emissions increased from 2004 to 2006 due to larger proportion of coal generation compared to gas, coal being around 6 times more NOx intensive.

We started to see a reduction in 2007 and will continue to show a decrease in NOx from coal from 2008 onwards as we have fitted additional abatement plant on the coalers to comply with 2008 LCPD restrictions. We will also show an overall drop in coal generation as Ironbridge and Kingsnorth are constrained by LCPD opt-out hours restriction.

We are also considering retrofitting Ratcliffe with selective catalytic reduction (SCR) technology. If we go ahead, this would be a first for a UK power station and it would significantly reduce NOx emissions.

Particulate Emissions per TWh (kiltonnes PM10 per TWh)

2003	2004	2005	2006	2007
0.016	0.013	0.021	0.027	0.02

PM10 = particulate matter smaller than 10 microns diameter

To minimise emissions of particulate matter, we use electrostatic precipitators to catch the dust before it leaves the stack. More than 90% of particles are captured during normal operation. Releases in excess of the norm are sometimes experienced during start up and shut down of units. These emissions are monitored and any excedence of emissions limits are notified to the Environment Agency.