10.4. EXPOSURE ROUTES
10.4.1. Inhalation and air pollution
Acronyms
10.4.1.1.
Introduction
Air pollution is the environmental factor with the
greatest impact on health in Europe and is responsible for the largest burden
of environment-related diseases. Air pollution, mainly by fine particles and
ground-level ozone, continues to pose a significant threat to human health: it
shortens average life expectancy in Western and Central Europe by almost one
year and threatens the healthy development of children. There are many examples
that show that respiratory health and life quality improve when air quality
improves.
In Europe, emissions of air pollutants are projected to
decline during the next two decades as a result of progressive implementation
of current and envisaged emission control legislation and continuing structural
changes in the energy system. The main contributor to air pollution in cities
is the continuing growth in road transport. Although the EU thematic strategic
on air pollution - setting objectives for 2020 – has brought some improvements,
it is clear that significant damage from air pollution will still remain in
2020. Meeting air quality targets will require efforts in other policy areas,
in particular in the energy, transport and agriculture sectors.
Poor indoor air quality is the source of a number of
health problems, including cancer, allergic symptoms, distress, sleeping and
concentration problems, and coughing, wheezing and asthma-like symptoms in
children. Many indoor problems are related to increased moisture and humidity,
part of which is a consequence of energy-saving policies that have led to
reduced rates of air exchange in homes, schools and office buildings. Other
indoor air quality problems arise from construction materials, paints,
household cleaning agents, environmental tobacco smoke and
combustion processes.
Despite a substantial body of international and national
legislation and significant reductions in the emissions of some common
pollutants, poor air quality is still associated with hundreds of thousands of
premature deaths in Europe every year. Air pollution by fine particles
represents the highest risk to public health in all regions of Europe. The health risks of air pollution by fine particles are at least in an order of
magnitude higher than those for other air pollutants (Clean Air for Europe, 2005).
Today, the drivers of the European air pollution problem
are different between European regions. However, traffic is the main
contributor. In North-West Europe, despite the economic growth, legislation on
air quality, together with associated abatement measures and economic
instruments, have led to a continuous decrease in emissions of air pollutants
since 2000. Emissions in South-Eastern Europe have generally followed a similar
trend.
In EECCA, economic recovery and the growth in transport
since 2000 have led to increases in the emissions of most air pollutants,
because of the poor effectiveness of protection policies. The age of the
vehicle fleet, low quality and high sulphur content fuel, poor infrastructure
and maintenance, and a declining share of public transport are the main causes
of environmental problems in this region. Industrial sources have declined in
importance, but remain relevant locally and are difficult to address.
Particulate matter and ozone are the main threats to
public health. Of special concern are, therefore, emissions of particulates and
particulate
precursors,
and emissions of the precursors of ground-level ozone.
Small particles, particularly if containing polycyclic
aromatic hydrocarbons (PAHs), and nano-particles have been identified as an
emerging risk. Interactions between air pollutants and natural particles such
as pollen have to be taken into account, and these are likely to be affected by
climate change and change of pollen seasons.
10.4.1.2. Data
Sources
This chapter is based on the European Environment Agency
(EEA) report ‘Europe’s Environment: the fourth assessment’ (chapters ‘Air
Quality’ and ‘Environment and Health Perspective’)” (EEA, 2007), and the
EEA/Joint Research Centre report “Environment and Health” (EEA, 2005).
·
Europe’s Environment: the
fourth assessment: 
http://reports.eea.europa.eu/state_of_environment_report_2007_1/en
·
Environment
and Health: http://reports.eea.europa.eu/eea_report_2005_10/en
EEA assessments are peer reviewed and quality checked by
scientific experts and policymakers at national authorities and the European
Commission Services.
WHO EURO, within it’s the ENHIS and ENHIS 2 projects on
environment and health information system based on indicators, proposed a list
of air pollution indicators. Not fully developed yet, this review is only
partly based on these indicators and mainly on scientific knowledge, assessments
and case studies in Europe.
The EC SCALE process, the Clean Air for Europe (CAFÉ)
process and several assessments made by WHO are also important building blocks
of this chapter, as well as several DG Research consortia.
·
European
Commission : http://ec.europa.eu/environment/air/air_en.htm
·
CAFE
CBA: http://cafe-cba.org/
·
WHO:
http://www.euro.who.int/air
·
EC4MACS:
http://www.ec4macs.eu/home/index.html
·
ExternE
Project: http://www.externe.info/
·
HEIMTSA:
http://www.heimtsa.eu/
·
INTARESE:
http://www.intarese.org/home.htm
Near real time information on ground-level ozone in Europe is available on the EEA website:
http://www.eea.europa.eu/maps/ozone/welcome
10.4.1.3. Data
description and analysis
Air pollution research and monitoring has led to a vast
amount of data that have been used in European air pollution management. This
presentation contains only some glimpses of data, compared to current European
guidelines, target values and limit values (Table 10.4.1.1).
Table 10.4.1.1. Guidelines, target values and limit values.
Long-term average exposure to particulate matters (PM10)
determines both the risks of chronic effects of pollution on children’s health,
such as impaired development of lung function, and the frequency of acute
effects, such as the aggravation of asthma or incidence of respiratory symptoms.
This indicator is also well correlated to the risk of a wide range of health
effects, including increased mortality, in adults. The measure of exposure
combines the PM10 concentration and the size of the population
subject to the exposure.
Most (89%) people (including children) in European cities,
where PM10 is monitored, are exposed to PM10 levels
exceeding the WHO air quality guideline level (AQG) (20 μg/m3)
(1), giving rise to a substantial risk to health. For 14% of people, the
European Union (EU) limit value of 40 μg/m3 is exceeded.
Figure 10.4.1.1 presents the total population distribution
of annual PM10 concentrations in 2004 (or the last available year);
Figure 10.4.1.2 shows the changes in exposure occurred in cities in the
2002-2004 period. This distribution is an approximation of the distribution of
the exposure of children based on the assumption of similarity in the
proportion of living children in cities.
Figure 10.4.1.1.
Percentage of children living in cities with various PM10 levels, 2004 or last
available year
Figure
10.4.1.2. Changes in exposure of children to PM10 in cities, 2002-2004
Air pollution management has today focused on fine
particles, generated primarily by traffic and with potential serious health
impacts. Table 10.4.1.2 here below describes the estimated health damage due to
PM2.5 and
the effect of the implementation of the current legislation in 2020.
Table 10.4.1.2. Estimated health damage due to PM2.5 in the EU 2000
and through implementation of current legislation (CL), in 2020
There is no doubt that pollutants in outdoor air have an
impact on respiratory health, as confirmed by a large number of epidemiological
studies on both short and long-term exposure. Many studies show that fine
particles (usually measured as PM2.5) have serious effects on health, such as an
increase in mortality and emergency hospital admissions for cardiovascular and
respiratory symptoms. Modelling results indicate that PM2.5 levels in Europe are
now estimated to reduce the statistical life expectancy of the European
population by approximately nine months, which is comparable to the impacts of
traffic accidents. The highest estimated damage to health occurs in the Benelux
area, in Northern Italy and in parts in Poland and Hungary, where the average
loss in life expectancy may be more than one year.
While much information is available for short-term acute
exposures, there is little data about the effect of long-term exposures. In a
study made in the former East Germany, an association was found between air
pollution levels in the city of residence, the presence of chronic respiratory
(especially bronchial) symptoms and lung function growth in children. A study
conducted in Switzerland also found an increased occurrence of symptoms in
children with increased air pollution levels. Several studies in the USA and
Canada (6-city study, 12-city and 24-city study) also found increased
bronchial, but not asthmatic, symptoms in children and lower lung function at
higher air pollution levels.
Much of the burden of diseases resulting from air
pollutants relates back to childhood. Air pollutants augment acute respiratory
infections in children and disturb the normal development of the lung.
Scientists and health-care professionals are focusing more and more on events
during foetal life and early childhood. There is growing evidence that these
periods are critical for the later development of many diseases that present
themselves during child and adult life. Children who grow up in polluted areas,
or whose parents grew up in polluted areas, are more likely to develop reduced
lung function as adults. Estimates show that the risk of reduced lung function
is doubled in children who grow up in urban areas. Children with asthma are
particularly vulnerable, but it is uncertain whether air pollutants trigger the
onset of childhood asthma. Intervention studies clearly show the health
benefits of improved air quality. Dublin, Ireland, and towns in former East Germany are typical examples. When considering human health and the quality of life,
the most urgent requirement to reduce the environmental burden on health
appears to be the improvement of the quality of outdoor and indoor air.
Air pollution is responsible for the highest burden of
environmentally-related diseases in Europe. Recent estimates indicate that 20
million Europeans a day suffer from respiratory problems. Air pollutants with
strongly-indicated respiratory health effects are particulate matter (PM),
especially fine and ultra-fine particles, which are able to penetrate the lower
respiratory tract (PM2.5), ozone (O3), nitrogen oxides (NO - NO2) and sulphur dioxide
(SO2). In addition, chemicals
such as polyaromatic hydrocarbons (PAH) and benzene from combustion processes
contribute to toxicity and potential health effects.
The WHO earlier estimated that particulate matter is
considered to be responsible for 100 000 deaths and 750 000 life
years lost annually in a selection of European cities (WHO, 2004). The more
recent estimates of the air pollution impact made within the European
Commission Clean Air For Europe (European Commission, 2005d) programme found
that in the EU about 350 000 people died prematurely in 2000 due to
outdoor air pollution with fine particulate matter (PM2.5) alone.
This corresponds to an average loss of life expectancy of about 9 months for
every EU citizen. Exposure to PM is also linked to an increased frequency of
chronic bronchitis, respiratory hospital admissions and days with restricted
activities for people suffering from respiratory and cardiovascular diseases.
The loss of statistical life expectancy attributed to
anthropogenic contributions to PM2.5., 2000 and 2020 is mapped on EEA data
service ( http://dataservice.eea.europa.eu/atlas/viewdata/viewpub.asp?id=3106)
In addition, current levels of ozone have severe health implications
such as bringing forward the deaths of more than 20 000 people (CAFE web
site http://europa.eu.int/comm/environment/air/cafe/index.htm
and the new www.cafe-cba.org web site).
The total cost of air pollution related health damage in
the EU in 2000 has been estimated by the CAFE programme in the range of Euro
305 billion to 875 billion, depending on the methodology used to assess the value
of a statistical life (VSL) and of life years lost (VOLY).
This estimated cost of non-action has to be
compared with cost of action focused on different sources of particles:
mobile sources (diesel passenger cars and heavy duty vehicles), industrial processes,
and domestic heating and cooking systems, including wood or coal stoves.
A new policy to reduce emissions of acid gases, ammonia
and fine particles is being developed within an EU Thematic strategy on air
pollution. The aim is to halve the health impact due to PM between 2000 and
2020, which would require action at both Community and national level. The cost
of action has been calculated at around Euro 10 billion per year for the EU as
a whole, if only technical measures are taken. When non-technical measures are
also considered the costs may be lower.
There are many examples that show that respiratory health
and life quality improves when air quality improves. This is clearly
exemplified by intervention studies such as the Dublin case study, the former
East Germany and the Atlanta case. There are also several studies which showed
a reduction in respiratory health effects associated to reduced air pollution
levels over several years in the former East Germany.
One of the best examples is the study carried out during
the 1996 summer Olympic games in Atlanta, USA in which the impact of changes in
transportation and community behaviour on air quality and childhood asthma was
investigated. Implementation of alternative transport strategy resulted in lower
traffic emissions and less hospital admissions of children with acute asthma
symptoms.
A part of the air pollution-related disease burden
consists of respiratory problems in children, who are exposed to outdoor and indoor
air pollutants in their homes, schools and day-care and during travel. The
quality of the indoor environment is particularly important since European
children spend more than 90% of their time indoors. Some of the mechanisms
through which
environmental factors influence children’s respiratory health remain unclear
and sometimes controversial. This is especially the case with asthma and
allergies.
Prevalence of asthma and allergies among children has
become an increasing problem in the last few decades (ISAAC, 2007) Asthma has
become the most common chronic disease among children and is one of the major
causes of hospitalization among those younger than 15 years of age. As more people are
sensitized to allergens, allergic diseases may increase in Europe in the coming
years.
In 1999–2004, asthma prevalence in children across the
European study centres (ISAAC) varied from less than 5% to over 20%. The
societal cost is estimated at 3 billion Euro/year. The well-documented rise in
asthma prevalence has coincided with a general increase in the density of road
traffic in most of these countries. A number of recent studies confirm that
residential proximity to traffic sources is associated with increased asthma
occurrence and exacerbations in both children and adults (11). In addition to
particles (PM), many studies indicate that ground-level ozone may be a critical
air pollutant. But the issue is still controversial. For example a number of
studies found allergic disorders (including asthma) to be relatively less
frequent in the eastern parts of Europe, although levels of many air pollutants
were higher than in Western Europe. Clearly, asthma has a multi-causal
background with many factors involved. “Life-style factors’ are important,
including the increased level of hygiene in homes and the contribution of
nutritional factors. Another important factor is genetic predisposition.
There is a lack of substantial knowledge about the
contribution of indoor air quality to respiratory symptoms and whether factors
in the indoor environment contribute to the increase in asthma prevalence.
Indoor air quality is therefore, receiving more and more attention, which is
logical in the light of the total time European children and adults spend
indoors. Indoor air pollutants can be classified into chemical, biological or
physical agents. Many outdoor air pollutants are found indoors, but there are
several specific indoor sources of air pollution, such as building and
construction materials, paints and indoor furnishings (furniture, carpets,
etc). Some indoor sources are linked to human activities and habits, such as
smoking, cooking and the use of cleaning agents, disinfectants and
air-cleaners. Open fires (wood, coal or gas) for heating, cooking and leisure
are significant sources. The continuing stress on energy-saving policies has
led to reduced air exchange in homes, schools and office buildings. This leads
to an increase in indoor humidity, which stimulates the development of
biological pollutants such as mites, moulds and bacteria. Ventilation-related
humidity problems arise in the warmer climatic zones of Southern Europe -
because of the increased use of air conditioners - as well as in the ¢cold‘ climates of central and
Northern Europe. Maintenance of ventilation systems is clearly important,
particularly regular cleaning or changing of dust filters.
Many acute health problems are connected to the indoor
environment, including allergic symptoms, distress, sleeping and concentration
problems, and in children, coughing, wheezing and asthma-like symptoms. Damp
and humidity are important factors because they provide a suitable environment
for the growth of micro-organisms (mould, bacteria) but also increase the
release of chemicals from construction materials. Several reviews find
respiratory problems, including asthma, in children from homes with visible
damp and mould or smell of mould. Several studies also highlight the importance
of the combined effects on children with allergic and asthmatic problems of
exposure to emissions from moisture and mould in combination with tobacco
smoke, emissions from gas stoves, mites and allergens from house
animals. Chemicals like formaldehyde and benzene from construction materials,
chemicals from treatment of furniture and decorations, fragrances from cleaning
agents and other household products add to the combined burden of the indoor
environment. Although the importance of the indoor environment is generally
recognised, there is far less knowledge about indoor than outdoor air quality.
There are several European directives that regulate outdoor air quality but no
European guidelines for indoor air quality. In the US, the Dept of Housing
& Urban Development has established emission standards for floor underlay
to address the issue of formaldehyde levels.
10.4.1.4. Control
tools and policies
During the 1999–2004 period the Framework Directive 96/62/EC on ambient air quality
assessment and management was complemented by four daughter directives. The
directive sets common objectives and basic principles, while the daughter
directives set limit and target values for the listed pollutants (European
Commission, 2005a; European Commission 2005b).
The air quality directives require EU Member States to
assess air quality throughout their territory. For zones and agglomerations
where the levels of one or more pollutants are higher than the limit value,
Member States are required to develop plans and programmes aimed at attaining
the limit values within the set time frame. In addition to establishing limit
or target values and alert thresholds for the identified pollutants, the
daughter directives aim at harmonisation of monitoring strategies,
measuring methods, calibration and quality assessment methods in order to arrive
to comparable measurements throughout the EU and provide effective public
information.
In 2001, the European Commission launched the Clean Air
for Europe (CAFE) programme. The main tasks of CAFE
are to inform and assist the development of a thematic strategy on air
pollution towards the long-term objective of the 6th
Environment Action Programme (6EAP), which was to
achieve levels of air quality that do not give rise to significant negative
impacts nor risks to human health or the environment, and to assess the
progress towards this objective.
The main objective of the CAFE Programme was
to develop long-term advice to protect against significant negative effects of
air pollution on human health and the environment (Holland et al, 2007)
The pollutants addressed were Emissions of
fine particles (PM2.5), NH3, NOx, SO2 and VOCs
and their reaction products (ozone and secondary particles).
The main outcomes of the CAFE Programme were
in the development of:
·
Thematic Strategy on Air Pollution
·
Directive on Ambient Air Quality and Cleaner Air for Europe (the CAFE Directive, COM (2005) 447)
·
Revision of the National Emission Ceilings Directive.
The Health impact Assessment in the CAFE
Programme was based on:
·
Development of methods
-
WHO, EC ExternE Project, other expert groups,
·
Main assumptions
-
Quantification against concentrations of fine particles and
ozone
·
Direct SO2 and NO2 effects omitted, less
evidence and concern over double counting
-
No threshold for particle effect at whole population level and a
35 ppb cut-off point used for ozone
-
More information on methods available at:
http://cafe-cba.aeat.com/files/CAFE%20CBA%20Methodology%20Final%20Volume%202%20v1h.pdf
Health effects quantified in CAFE CBA
included:
·
Chronic exposure:
o
Mortality (PM) – the dominant effect
o
Development of bronchitis (PM)
·
Acute exposure (daily variations)
o
Mortality (O3)
o
Hospital admissions
·
Respiratory (PM,O3); Cardiovascular (PM)
o
Days of restricted activity; days off work (PM,O3)
o
Days with symptoms (PM, O3)
·
In people with chronic lung disease (sthma, COPD)
·
In the general population
Evidence for effects was achieved through:
·
Consistency of a very large number of time-series studies
-
Acute effects on mortality
-
Acute effects on respiratory hospital admissions
·
Intervention studies
-
Dublin, Hong Kong, etc.
·
Cohort studies
- Pope et al and
re-analyses
Table 10.4.1.3. The CAFE analysis and the strategy
The need to revise current air quality protection
legislation was revealed by analysis under the CAFE programme that showed that
the health risk of pollution by fine particles was of an order of magnitude
higher than that of the other pollutants (European Commission, 2005b).
Following the CAFE analysis of the various scenarios, the
Commission adopted in September 2005 its thematic strategy on air pollution by
establishing interim environmental objectives for 2020 and setting the level of
ambition regarding air quality in the EU up to 2020 (between scenario A and B
above). Although this means some improvements, it is clear that significant
damage from air pollution will still remain in 2020. The Commission also made
it clear that meeting air quality targets will require efforts in other policy
areas, in particular in the energy, transport and agriculture sectors.
The Commission proposal is for a new directive (EC 2005a)
that would mean retaining the current PM10 standard and adding a new standard
for PM2.5 – with the so-called concentration cap of 25 µg/m3 as annual mean –
to be met by 2010, and the revision (currently under preparation) of the
directive on national emission ceilings (NEC), which sets binding requirements
for maximum 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.
Air quality protection policy of South-eastern European
countries is driven by the overall goal of joining the EU, and their efforts
and cooperation have focused mainly on this process. The countries and
territories of the region are at various stages of accession or association and
stabilisation. Bulgaria and Rumania became Member States in 2007 and harmonised
their air quality protection legislations with the EU within the framework of
the accession process.
The most effective policies for controlling air pollution
relate to the further reduction of emissions, for example through improving
fuels, setting emission limits for industry and efficiency standards for
buildings and equipment and reducing demand for polluting activities.
Those policies can be strengthened through the use of air
quality standards and national emission ceilings, and also by linking climate
and air quality policies.
Most of this action clearly falls outside the health
community, so we need to ask what the role of the health community should be in
pursuing health improvements via reduced emissions of air pollutants.
In particular, effective pollution control policies can be
summarized as:
·
Fuel quality
standards
·
Emission
limits for industry, vehicles
·
IPPC for
major industry
·
Efficiency
standards for buildings and appliances
·
Linkage of
climate and air quality policies
·
Reduced
demand for polluting activities
·
Air quality
standards
·
National
emission ceilings; and
·
Pricing in
energy and fuels.
10.4.1.5. Future
developments
The issue of air pollution and health is characterised by
combined exposures, where also the importance of indoor air has increasingly
been recognised.
Damage to health is caused primarily by two types of air
pollutants, namely fine particles and ozone. Concentrations of fine particles
have a much more important effect than ozone with respect to mortality. Special
attention should be given to those particles that, in laboratory trials, show
the highest toxicity and often occur in hotspots. These include fine and
ultrafine 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”. 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 desirable to achieve reduction in the background levels, since long-term
exposure accounts for the majority of the most serious health effects.
Small particles and nano-particles have been identified as
an emerging risk. Interactions between air pollutants and natural particles
such as pollen have to be taken into account, and these are likely to be
affected by climate change and change of pollen seasons.
In relation to a possible role of the Health Community,
according to Holland at al (2007), it is important that health professionals
quite generally recognise the links between health and what historically would
be considered as low levels of air pollution. This may not be obvious, given
that air pollution is ubiquitous and that it may well act in combination with
other stresses. Recognising the problem has two important benefits; first, it
makes it possible to raise awareness amongst sensitive groups; second, it
increases the interest for research in the area, whether it be on new
epidemiological and toxicological studies or on the development of integrated
frameworks for health assessment, as under projects such as EC4MACS, ExternE,
HEIMTSA and INTARESE.
Most important, however, the health community should
become more involved in the debate on air quality. Whilst specific actions to
reduce emissions need to be taken by other groups, it is after all the health
community that will have to experience the impacts.
10.4.1.6.
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