Air Quality - Environmental Audit Committee Contents

2 The air quality problem

Heath effects of poor air quality

6.  Poor air quality leads to poor human health. There are short-term effects on, for example, the respiratory system, and more serious impacts due to long-term exposure including permanent reductions in lung function. Air pollution has been linked to asthma, chronic bronchitis, heart and circulatory disease, and cancer.[4]

7.  Particulate matter is thought to have the most damaging impact on health with adverse effects to health seen at very low concentrations.[5] Ozone and particulate matter are linked to summer smog episodes; it has been estimated that there were between 225 and 593 additional deaths due to increased ozone in the first 2 weeks of August, during the 2003 heatwave, compared to the year before. 207 additional deaths have been attributed to increased concentrations of particulate matter during the same period. For England and Wales, the deaths due to air pollution accounted for 21-38% of the total reported excess deaths during the 2003 heatwave. Climate change is likely to make air quality problems worse.

The Government's advice

8.  The Committee on the Medical Effects of Air Pollutants (COMEAP) is an Advisory Committee of independent experts that provides advice to government departments on the health effects of air pollutants. In 1998 COMEAP estimated that on average up to 24,000 people in the UK die prematurely every year as a result of short-term exposure to air pollution and thousands more are hospitalised. This figure has been used in several recent reports including the Cabinet Office report, The Wider Costs of Transport in English Urban Areas in 2009, and in the Royal Commission for Environmental Pollution's 2007 report on the urban environment. The Air Quality Management Resource Centre, at the University of the West of England, told us that when this figure was first published there was a general feeling that it was too high and an assumption that over time it would be found to be lower. COMEAP is currently re-quantifying the health effects of air pollution. In June 2009 it published Long-term Exposure to Air Pollution: Effect on Mortality. This put forward quantitative estimates of the effects of long-term exposure to particulate pollution on mortality. It suggested that particulate matter has a greater effect on mortality in the UK than previously thought.

9.  Professor Frank Kelly from the Environmental Research Group at King's College London explained that if new evidence was taken into account the 1998 figure of 24,000 premature deaths per year would rise to 35,000.[6] Research by the European Environment Agency suggested that the figure could be as high as 50,000 for the UK. In the case of London, Professor Kelly told us that new evidence would support a figure of around 3,500 early deaths per year. Studies in other countries have suggested that the risks from poor air quality could be even higher. If the more extreme figures suggested by this work were used the estimate of the number of early deaths in London could be as high as 8,000. Initial concerns that COMEAP's 1998 figure was an over-estimate appear, in the light of new evidence, to have been wrong.

10.  The Government's current 2007 Air Quality Strategy estimates that particulate matter reduces life expectancy by around seven to eight months, averaged over the whole population of the UK. This is an average and for individuals who are particularly sensitive and are exposed to the poorest air quality the reduction in life expectancy could be as high as 9 years.[7] The Department of Health commissioned work from the Institute of Occupational Medicine[8] to compare the benefits of eliminating man-made PM2.5 with the elimination of motor vehicle traffic accidents and the elimination of exposure to passive smoking. The results are shown in table 1.Table 1: Comparison of the benefits of reducing PM2.5 by 10 µg/m3 (equivalent to eliminating man-made PM2.5 in 2005), the elimination of motor vehicle traffic accidents and the elimination of exposure to passive smoking
Reduction in PM2.5
Elimination of road traffic accidents
Elimination of passive smoking
Expected gain in life expectancy 7-8 months1-3 months 2-3 months
Estimated equivalent gain in life years in England and Wales from 2005-2110 for the whole population (including people born during that time) 39,058,0008,126,000 13,194,000

Source: Department of Health, Ev 142

EU targets

11.  The UK is failing to meet some of its EU and domestic targets, nor is it on course to meet others that will come into force in the future.


12.  The European Commission has launched infringement proceedings against the UK for failing to comply with the air quality standard for PM10. In April 2009 DEFRA submitted a notification to secure additional time, until 2011, to comply with the limit values for PM10. London is the only part of the UK still failing to meet PM10 limit values. It has the worst air quality in the UK and the worst in Europe for particulate matter and NO2.[9] On 11 December 2009 the European Commission refused to grant an extension. DEFRA and the Mayor of London will now be forced to agree a more convincing plan to justify its claim for an extension and avoid potentially significant EU fines. Since limits on PM10 came into force in 2005, Ireland and Luxembourg are the only EU member states not to have exceeded limit values.


13.  The UK now also faces proceedings from the EU for failing to meet the limits for NO2 that came into force in January 2010. Defra said that meeting EU limits values for NO2 in areas of exceedence presents a much more significant challenge and will require specific actions to limit emissions from transport in urban areas. Rural NO2 levels across the UK are slightly lower than the EU average but NO2 concentrations at urban background sites are about 20% higher than the EU averages.[10] Similarly, at roadside sites UK mean NO2 concentrations are higher than the EU roadside averages by about 20%.

14.  The UK is predicted to fail the NOX emissions ceiling target imposed by the European National Emissions Ceiling Directive. Emissions are projected to be 1,210 ktonnes in 2010, which just exceeds the legal limit. Twelve other EU Member States are also projected to miss the 2010 emission ceiling for NOX.[11]

15.  Power station emissions will be a significant factor if we fail to meet emission ceiling targets. In a recent assessment of power stations, six of the ten most polluting emitters in the EU were found to be in the UK. This is largely because decisions were made by the Environment Agency—based on the limited life of plants and the costs involved—not to require UK coal fired power stations to fit selective catalytic reduction technologies to reduce NOX emissions.[12] Such technologies are more widely used in other European countries. Although power stations emissions have little impact on roadside NO2 and on our failure to meet NO2 limit values, they do contribute significantly to the formation of particulate matter and damage to ecosystems.


16.  Ozone concentrations have been steadily increasing over the last decade in urban areas, due to reductions in emissions of NOX in these areas. If this trend continues future ozone concentrations could exceed target values and long-term objectives will be missed.

17.  Concentrations of ozone are heavily dependent on the weather and trans-boundary pollution, making it a difficult pollutant to regulate and control. International cooperation is essential to reduce the emissions of the pollutants that react in the atmosphere to form ozone. The European Commission is expected to publish a proposal to revise the National Emission Ceilings Directive.[13] This is likely to include tighter emission ceilings for ammonia, sulphur dioxide, NOX and volatile organic compounds that must be met by 2020 and this will indirectly help tackle ozone pollution.

18.  The lives of many people in the UK could be extended by tackling air quality. We recognise that the Government has access to high quality advice from UK experts, such as COMEAP. But warnings about the impact poor air quality has on health are not being widely publicised. More should be done to update the figures the Government uses in its appraisal of policies. Environmental Protection UK, an environmental charity, said that the evidence about the health effects of air pollution was not communicated clearly across Government or to the general public.[14] The Mayor of London agreed that air quality issues were neglected by decision makers at all levels of government, primarily because of ignorance. Information has not been given to relevant stakeholders on the health effects of air pollution in the areas of poorest air quality.[15]

19.  The scientific evidence suggests that the number of premature deaths caused by air quality has been underestimated. New evidence on the longer-term impacts shows that greater gains in life expectancy could be achieved by tackling air quality than are currently being realised by efforts to eliminate road deaths and passive smoking combined. Air quality must be a higher priority for Government. Defra must raise the profile of the issue by publicising the latest data on premature deaths more widely and making clear the benefits of improving air quality.

4   NAO, Air Quality, January 2010 Back

5   NAO, Air Quality, January 2010 Back

6   Q 66 Back

7   Ev 93 Back

8   Institute of Occupational Medicine, Comparing estimated risks for air pollution with risks for other health effects, March 2006 Back

9   NAO, Air Quality, January 2010 Back

10   NAO, Air Quality, January 2010 Back

11   NAO, Air Quality, January 2010 Back

12   Q 184 Back

13   NAO, Air Quality, January 2010 Back

14   Ev 65 Back

15   Ev 2 Back

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Prepared 22 March 2010