|
| News | Policy initiatives | Acidification & Eutrophication | Air quality | Climate Change| Publications | Events | Links | The Secretariat |
 |
|
|
Particles and health Factsheet from the Swedish NGO Secretariat on Acid Rain. April 2006.
A large number of studies carried out in both the US and in Europe have shown that when the concentration of small particles in air rises, even from low levels, there is a rise in mortality from respiratory, cardiac and circulatory diseases, and more people seek hospital care for bronchitis and asthma. WHO (2005a) summarizes the state of knowledge as follows: - Particles (PM) in general increases the risk of respiratory death in infants younger than one year, affects the rate of lung function development, aggravates asthma and causes other respiratory symptoms such as coughs and bronchitis in children. - Fine particles (PM2.5) seriously affect health, increasing deaths from cardiovascular and respiratory diseases and lung cancer. Increased PM2.5 concentrations increase the risk of emergency hospital admissions for cardiovascular and respiratory causes. - Coarse particles (PM10) affects respiratory morbidity, as indicated by hospital admissions for respiratory illness. People are not all affected equally by air pollutants – certain sections of the population are much more sensitive than average. These include children, the elderly and those with underlying disease, such as respiratory disorders. Short-term exposure WHO (2005a) states that short-term changes in PM10 at all levels lead to short-term changes in acute health effects. Effects related to short-term exposure include inflammatory reactions in the lungs, respiratory symptoms such as cough and bronchitis, adverse effects on the cardiovascular system and increases in medication use, hospital admissions and mortality. Although long-term exposure gives rise to the most serious health effects (see below) the acute effects that arise from short-term exposure to high concentrations are important, since they affect a large proportion of the population, for example in the form of restricted activity days (see table 1). WHO stresses that, based on known health effects, both short-term (daily) and long-term (annual), guidelines are needed for fine as well as coarse particles. Long-term exposure Because long-term exposure to PM results in a substantial reduction in life expectancy, the long-term effects clearly have greater significance to public health than the short-term effects (WHO 2005a). The effects of long-term exposure include increases in lower respiratory tract symptoms and chronic obstructive pulmonary disease, reductions in lung function in children and adults, and reduction in life expectancy, due mainly to cardiopulmonary mortality and probably to lung cancer. These effects are demonstrable even at levels well below the limit values. PM2.5 shows the strongest association with mortality: An increase in long-term concentration of PM2.5 by 10 µg/m3 increases the risk of deaths from all causes by 6 per cent. These estimates are based on exposure comparisons between cities, and assume that all residents of a city have the same average exposure levels. But recent research in California has shown that assessments of exposure that are based only on community average concentrations may lead to an underestimation of the health risks by a factor two or three (EC 2005d). Table 1. Estimated health damage due to PM2.5 in the EU 2000 and through implementation of current legislation (CLE) 2020.
Source: EC 2005c. Significance of size and origin It is the very smallest particles that are believed to be the most harmful, because when they are inhaled they can penetrate deep into the lungs. The focus of debate is now turning to PM2.5. However, many researchers point out that coarse particles (PM2.5–PM10) also have considerable health effects and their levels also need to be reduced. The shape and chemical composition of the particles as well as their size are thought to influence their harmfulness, as do the substances that adhere to their surfaces. At present it is not possible to distinguish between the health effects of particles with different origins, so for the time being all particles in the same size range are regarded as equally harmful. Toxicology studies indicate, however, that so-called primary particles from combustion have a higher toxic potential than secondary particles (see box 2). These primary particles are often rich in metals and organic compounds, and also have a relatively high surface area (WHO 2004a). Knowledge of the concentrations in the air and the links that exist between exposure and response makes it possible calculate the effects. Although these calculations do involve some uncertainties they still give a clear indication of the scope of the problem. Effects in Europe 2000 In the EU thematic strategy on air pollution (EC 2005a) the health effects of levels of fine particles (PM2.5) in the air in the year 2000 are estimated to lead to an average shortening of statistical life expectancy of more than eight months in the EU, equivalent to 3.6 million life years lost annually. This effect is comparable to the loss of life expectancy due to road accidents in the EU, even though it does not include secondary organic aerosols and only refers to impact on the population over 30 years of age, thus underestimating the total impact. Figures for each country are given in table 2. Geographically, the greatest damage to health occurs in the Benelux area, in northern Italy, and in parts of Poland and Hungary. In these areas, the average loss in life expectancy may be more than one year. See Figure 1. In addition to premature deaths, particles cause a range of other effects on people’s health, including increased need for respiratory medication in adults and children and almost 350 million days of restricted activity in 2000, see table 1. Effects in Europe 2020 Under the current legislation scenario the average loss of life expectancy in the EU caused by PM2.5 is expected to drop from 8 months in 2000 to 5.5 months in 2020. The number of life years lost will fall from 3.6 to 2.5 million, see table 1. Bigger improvements are possible if further measures are taken to reduce levels. The effects on life years lost and premature deaths of implementing the thematic strategy and technically feasible reductions are shown in table 2. Figure 1. Loss of statistical life expectancy that can be attributed to anthropogenic contributions to PM2.5 (months). For the emission levels in the year 2000 (left), and for two projected emission levels for 2020: CLE (centre) and MTFR (right). Cleaner air brings huge benefits Improvements in health generate the largest quantified monetary benefits when air pollution is reduced. The European Commission (EC 2005c) shows that the benefit of reducing the average background concentration of PM2.5 by 20–25 per cent between 2010 and 2020 is estimated to be between 37 and 119 billion euro per annum in 2020. These figures are between five and 24 times higher than the estimated costs, which range between 5 and 8 billion euro per annum. The World Health Organization, WHO, has until recently been unwilling to set any air quality guidelines for particles, since it is considered unlikely that a level will be found that does not have harmful effects. Instead, it has given a dose-response relationship, that can be used to calculate for example how many people would be affected by a given level of particles in the air. In the revised WHO air quality guidelines that were adopted in autumn 2005 (WHO 2005c) it is stated that the link between exposure and effects can still be used, depending on local circumstances, to establish limit values. But numerical values are also given to provide guidance on the concentrations at which increasing, and specified mortality responses due to PM are expected based on current scientific insights, see table 3. A working group under the CAFE programme reported in a position paper (CAFE 2004) that for health reasons the EU should aim for a reduction in annual mean concentrations of PM2.5 to levels of around 10 µg/m3 or lower. In the short term, by 2010, the group recommended that limit values in the range 12–20 µg/m3 should be considered. EU limit values Limit values for PM10 were adopted in 1999. The directive came into effect in 2001, and the PM10 limit values became legally binding in the EU in January 2005, see table 3. In September 2005 the Commission presented a proposal for a new directive (EC 2005b) that would mean retaining the current PM10 standard and adding a new standard for PM2.5 – as so called concentration cap of 25 µg/m3 as annual mean – to be met by 2010. As a rule of thumb, levels of PM2.5 are around 60–70 per cent of PM10 levels, so the proposed concentration cap for PM2.5 does not represent any strengthening of requirements in relation to the PM10 standard that is already in force. On the other hand the proposal allows a number of concessions to the current regulations, including more time for countries to meet the limit values and the opportunity to discount pollutant contributions from natural sources for compliance purposes (see box 1 for details). To complement the new concentration cap it is proposed that member states should reduce average human exposure to urban background levels of PM2.5 over the period 2010–2020. A general, non-binding 20-per-cent reduction is proposed. The United States In 1997 the USA set an annual limit value of 15 µg/m3 for PM2.5 which is to be met by 2010. The state of California has had a limit value of 12 µg/m3 since 2003. In a review of the federal limit value that was carried out in 2005 a Staff Paper from the Environment Protection Agency proposes that in light of the latest scientific information the limit value should be reduced, and levels as low as 12 µg/m3 are being discussed (US EPA 2005). Table 3. Guidelines, target values and limit values.
(A) European Union 1999, Directive 1999/30/EC. (B) Interim values in present directive (1999/30/EC). In the proposal for the new directive (EC 2005b) the Commission want to eliminate these, however. (C) IMM = National Institute of Environmental Medicine, Sweden, 2000. (D) EC 2005b. (E) Should be reduced to 35 µg/m3 according to proposal by EPA in December 2005. (F) CAFE 2004. Emissions of primary particles Emissions of primary particles are considered to have fallen in recent decades, but the true extent is still inadequately known. According to the EU thematic strategy on air pollution, emissions of primary particles (PM2.5) in 2000 totalled 1,744,000 tonnes in the EU25. The emissions by country is shown in table 4. According to the baseline scenario (current legislation) that is used in the thematic strategy, emissions of PM2.5 would fall by 45 per cent between 2000 and 2020 (to 969,000 tonnes), mainly as a result of stricter emission standards for cars and heavy vehicles. See table 4. Emissions from international shipping in European waters are expected to rise over the same period from 210,000 to 330,000 tonnes. It is possible to achieve larger reductions in emissions than predicted under the baseline scenario if additional measures are taken. If the thematic strategy is implemented, emissions of primary PM2.5 from land-based sources in the EU would fall to 712,000 tonnes in 2020. The maximum technically feasible reduction is calculated as 606,000 tonnes by 2020 (again, see table 4). Note that the figures above refer solely to emissions of primary particles. A significant proportion of the particles that are found in the atmosphere are, however, secondary particles formed from other pollutants, particularly nitrogen oxides, sulphur dioxide and ammonia. See Box 2. Table 4. Emissions of primary particulates (PM2.5) in 2000 and in 2020 for three scenarios: Current legislation (CLE), Thematic Strategy (TS) and Maximum technically feasible reductions (MTFR).
Distribution by sector At EU level the household and transport sectors account for the largest emissions of primary particles (PM2.5), see figure 2. The household sector is dominated by emissions from domestic wood stoves while transport is dominated by diesel engines. Figure 2. Emissions of PM2.5 per sector in EU25, year 2000 (left) and 2020 baseline scenario (right). Source: EC 2005c. --- Special attention should be given to those particles that, in laboratory trials, show the highest toxicity and often occur in hotspots. These include particles from combustion processes, and particularly exhaust fumes from diesel engines. A large, but unregulated source, is domestic wood stoves. In urban areas, up to 10 per cent of the population may be living in such “hot spots”. WHO concludes that the public health burden of such exposure is significant (WHO 2004b). It is important that abatement programmes do not focus solely on meeting the relevant limit values for PM10, as this could mean that too great an emphasis is placed on the largest particles. These admittedly represent the largest fraction by weight, but are not likely to have the biggest effect on health. It is also important to avoid focusing solely on local hotspots where limit values are exceeded, such as areas with heavy road traffic. It is at least as desirable to effect a reduction in the background levels, since it is long-term exposure that accounts for the majority of the most serious health effects. A significant proportion of the regional background level consists of secondary particles (see box 2). Reducing the level of these particles requires measures in those sectors of society that produce large emissions of sulphur dioxide, nitrogen oxides and ammonia. The Commission is currently preparing the revision of the directive on national emission ceilings (NEC), which sets binding requirements for maxium total emissions of sulphur dioxide, nitrogen oxides, volatile organic compounds and ammonia, for each member state. A proposal for a revised directive that will require more far-reaching reductions in the air pollutants that act as precursors to secondary particles, is foreseen by mid-2007. The proposal may include national emission ceilings also for primary particles. CAFE 2004. Second Position Paper on Particulate Matter. CAFE Working Group on Particulate Matter. 20 December 2004. EC 2005a. Thematic Strategy on Air Pollution. COM(2005) 446. EC 2005b. Proposed Directive on Ambient Air Quality and Cleaner Air for Europe. COM(2005) 447. Can be downloaded at http://europa.eu.int/comm/environment/air/cafe EC 2005c: Commission staff working paper: Impact assessment of the thematic strategy on air pollution and the directive on “Ambient air quality and cleaner air for Europe”. SEC(2005) 1133. EC 2005d. Science for Environment Policy. DG Environment News Alert. 5 December 2005. IMM 2000. Particles in ambient air – a health risk assessment. Pershagen, G. (Ed.). Scandinavian Journal of Work, Environment & Health. Vol. 26, suppl. 1, 2000. US EPA 2005. Review of the National Ambient Air Quality Standards for Particulate Matter: Policy Assessment of Scientific and Technical Information. QAQPS Staff Paper. EPA-452/R-5-005. www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html WHO 2000. Air Quality Guidelines for Europe. Second Edition. WHO Regional Publications, European Series, No. 91. WHO 2004a. Health Aspects of Air Pollution. Results from the WHO Project “Systematic Review of Health Aspects of Air Pollution in Europe”, June 2004. WHO 2004b. Health Aspects of Air Pollution – answers to follow-up questions from CAFE, Report on a WHO working group meeting, Bonn, Germany 15-16 January 2004. Available at www.euro.who.int/document/E82790.pdf. WHO 2005a. Particulate matter air pollution: how it harms health. Fact sheet EURO/04/05. Berlin, Copenhagen, Rome, 14 April 2005. WHO 2005b. Press Release EURO/08/05. Berlin, Copenhagen, Rome, 14 April 2005. WHO 2005c. WHO air quality guidelines global update 2005. Report on a Working Group meeting, Bonn, Germany 18-20 October 2005. Available at www.euro.who.int/Document/E87950.pdf Particulates and health The above reports from WHO give a good summary of the current state of knowledge. Available along with other relevant material from WHO Europe, www.euro.who.int (select “Health topics” and then “Air”). The CAFE programme and the thematic strategy on air pollution Summarized in a fact sheet from the secretariat, available at www.acidrain.org. See also the Commission’s website, http://europa.eu.int/comm/environment/air/cafe/. Here you can find the strategy itself, an impact assessment and the CAFE position paper mentioned above (CAFE 2004). NGO positions European environmental NGOs have prepared position papers for both the thematic strategy on air pollution and the proposed directive on ambient air quality and cleaner air for Europe (COM(2005) 447). Available here. What can be done at local level “A Breath of Fresh Air” (2002) is a fact sheet from the European Environmental Bureau (EEB) explaining EU legislation and possible local action to improve air quality. Available at www.eeb.org.
|
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Also available in pdf format: 
