In a strategy that focuses on the long-term implications to human health of particle emissions from traffic and industry, medical experts have conducted a wide-ranging review of scientific, technical and economic evidence.
The proposals for Scotland are tighter than for anywhere else in the UK but computer modelling and monitoring work indicate they should be achievable.
Deputy minister for environment and rural development Rhona Brankin said:
'Air quality is improving year on year. We have seen significant reductions in recent years in the levels of particle air pollution as new policy measures to reduce emissions from industry and traffic take effect.
'But the latest advice from health experts shows that particle air pollution continues to have a significant impact on health. Recent evidence suggests that long-term exposure to particle air pollution can contribute to a number of serious health problems, including heart disease. It is clear that we must do more.
'The proposals published today involve a significant strengthening of our air quality targets for particles and other important air pollutants. They confirm the Executive's commitment to respond promptly to the latest advice from health experts.'
The UK department of health's Committee on the Medical Effects of Air Pollution (COMEAP) considers that the long-term effects of particle air pollution on health are at least ten times greater than the short-term effects on which present policies are based.
Ms Brankin said that the executive believed the latest expert evidence pointed firmly to the need for further action to ensure that levels of particles in air continue to fall. Today's new targets, set in response to COMEAP's findings, are intended to encourage significant further reductions in particle air pollution and improvements in the nation's health.
The new target for 2010 aims to cut long-term pollution levels by at least 50% so that:
* for Scotland, the target is a 24-hour mean of 50 m g/m3, not to be exceeded more than 7 times a year, and an annual mean of 18 m g/m3 to be met by end 2010
* for UK, except London and Scotland, the target is a 24-hour mean of 50 m g/m3, not to be exceeded more than 7 times a year, and an annual mean of 20 m g/m3 to be met by end 2010
* for London, the target is a 24-hour mean of 50 m g/m3, not to be exceeded more than 10 - 14 times a year, and an annual mean of 23-25 m g/m3 to be met by 2010
It is also proposed that the mayor of London and the city's local authorities should work towards a provisional annual mean of 20mg/m3 after 2010, with the aim of achieving it by 2015 where cost effective and proportionate local action can be identified.
Today's proposals also involve tougher targets for benzene and carbon monoxide and, for the first time, a target for polycyclic aromatic hydrocarbons (PAH). The targets proposed for benzene and PAH both reflect latest health advice. The target for carbon monoxide has been strengthened in response to the recently agreed EU limit value.
1. Air Quality Strategy
The latest Air Quality Strategy was published in January 2000. The Strategy is part of the UK government and devolved administrations' overall aim to improve the quality of life across the UK. It sets targets for reducing levels of eight important air pollution and the framework in which everyone, from individuals to big business, has a role to play in improving air quality.
The Strategy explains that the present target for particles to be met across the UK by the end of 2004 is seen as a staging post and not a final outcome; work had been set in hand to consider the prospects for strengthening the target.
Particles and health - Advice from Committee on Medical Effects of Air Pollutants (COMEAP)
The new targets for particles announced today are the outcome of a wide-ranging review of scientific, technical and economic evidence. It is in particular a response to the latest advice from the Committee on the Medical Effects of Air Pollutants (COMEAP) which suggests that people exposed to particles over the long term are at greater risk of premature death, particularly from heart disease.
Particles are associated with a range of short-term health effects, including effects on the respiratory and cardiovascular systems, asthma and death. In its 1998 report, the UK Dept of Health's expert Committee (COMEAP) suggested that that in 1996 the early death of 8,100 vulnerable people and 10,500 hospital admissions in the UK were associated with respiratory disease affected by particle air pollution. These deaths are among people who are already very ill and are likely to be brought forward by a few weeks.
COMEAP has since looked at the health effects from long-term exposure to particle air pollution. In its report published on 1 May 2001, the Committee suggests that emerging evidence points to the chronic health effects of particle air pollution being substantially more significant than the acute effects. The Committee considers that on the basis of studies carried out in the United States, an estimated 0.007 to 4.1 million life years might be gained in this country per 1m g/m3 (microgramme per cubic metre) drop in concentrations of particle air pollution. This represents a reduction of about 5% on present levels. The wide range reflects the uncertainties involved. The Committee takes the view in its report that an estimate towards the lower end of the range (0.2-0.5 million life years across the population) is more likely.
This represents an average gain of 1.5 to 3.5 days per person. However, although everyone is exposed, it is likely that only some of the population is susceptible to the adverse effects of long term exposure to air pollution. This would mean that some people would not gain anything, whilst those affected would gain more than the average figure of a few days. For example, if only 1 million rather than 52 million people were affected, the gain would be around 3 to 6.5 months per person. The Committee's report explains that the number of people affected is unknown, and so an accurate calculation of the gain in the susceptible population is not possible.
This effect is at least 10 times greater than the short-term health effects of day to day changes in particle air pollution suggested by the Committee in its 1998 report.
2. Sources of particles
Particles (PM10) have three predominant source types. Concentrations of PM10 consist of primary particles, arising from combustion sources (including road traffic), secondary particles, mainly sulphate and nitrate formed by chemical reactions in the atmosphere, and coarse particles, suspended soils and dusts, seasalt, biological particles and particles from construction work.
PM10 is composed of each of the three source types. In general terms, the three source types each make up roughly one-third of total long-term average PM10 concentrations at urban background locations. However, the relative contribution of each source type varies from day to day, depending on meteorological conditions and quantities of emissions from mobile and static sources. The fine particle fraction (PM2.5) is composed predominately of primary and secondary particles. Coarse particles are particles in the range from PM2.5-PM10.
UK emissions account for about 80% of the primary fraction. Emissions in mainland Europe contribute up to about 20% to primary particles in the UK. This may be much larger during short-term peak episodes. Emissions from mainland Europe make a more significant contribution to secondary particles. In a year with typical meteorology, about 15% of total annual average PM10 concentrations (about 50% of secondary particles) are derived from mainland Europe. In years when easterly winds are more frequent, emissions from mainland Europe account for a much higher proportion particularly in south and east England.
3. Air Quality Strategy's present objectives - new proposals
Particles (as PM10)
24-hour mean of 50 m g/m3 not exceed more than 35 times a year
annual mean of 40m g/m3
both to be met by end of 2004
24-hour mean of 50 m g/m3 not exceed more than 7 times a year
annual mean of 18m g/m3
both to be met by end of 2010
UK (apart from London & Scotland)
24-hour mean of 50 m g/m3 not exceed more than 7 times a year
annual mean of 20m g/m3
both to be met by end of 2010
24-hour mean of 50 m g/m3 not exceed more than 10-14 times a year
annual mean of 23-25 m g/m3
with the aim of this being met by 2010
It is alsoproposed that the Mayor and London local authorities should work towards a provisional annual mean of 20mg/m3 after 2010, with the aim of achieving it by 2015 where cost effective and proportionate local action can be identified
4. Action to reduce particles
The Executive has already set in place a range of measures that will help to reduce emissions of particles. A Transport Delivery Plan for Scotland, to be published in the autumn, will set out proposals for tackling traffic congestion and reducing pollution over the next 10-15 years. Tighter European vehicle emission and fuel standards already in place and coming in during the next few years will reduce emissions of particles and other air pollutants substantially. The new Integrated Pollution and Prevention Control (IPPC) authorisation regime for industrial processes will also contribute to the downward trend in particle air pollution.
4.1 Trend in air pollution
The trend in urban air quality is continuing to improve. The UK Environment Minister Michael Meacher announced on 4 May this year (DETR News Release No.ENV-011) that in 2000 in urban areas there were 16 days of moderate or higher air pollution on average per site, the lowest figure recorded since the series began in 1993. Days of moderate or higher air pollution caused by particles have fallen from 34 in 1993 to 5 in 2000.