n. 7 Aug 2009 Marco Moro
n. 6 Jun 2009 Marco Martuzzi
n. 5 Apr 2009 Serenella Iovino
n. 4 Aug 2008 Seamus Egan
n. 3 Apr 2008 Giovanni Allevi
n. 2 Feb 2008 Marco Bicego
n. 1 Nov 2007 Jan Garbarek
Comete
Online bimonthly
Reg. at Vicenza Court No. 1165 on 18 December 2007
Editor and director Bianca Nardon
Redazione STEP Srl Contrà Porti, 3 Vicenza
Year III no. 6 June 2009
Meeting with Marco Martuzzi
World Health Organization Epidemiologist
'Health impact of PM10 and ozone in 13 Italian cities' - World Health Organization, Regional Office for Europe, 2006
www.euro.who.int/document/e88700.pdf
A WHO report of 2006 on the effects of PM10 and ozone in thirteen Italian cities shows that 'In the years 2002-4, an average of 8220 deaths per year were due to the long term effects of PM10 concentrations above 20 µg/m3, which is equivalent to 9% of mortality by all causes except accidental ones (traumatisms and poisoning) in the population over 30 years of age'.
How can these deaths be related to specific health effects (heart attack, lung cancer etc.) caused by air pollution?
Although there are many open questions on which research work continues, the subject of air pollution and PM in particular is one of the most established in the environmental field. We have evidence that is numerically very firm and accurate on the health effects of PM and we are fairly sure of the causal link. We know that along with the increase in PM concentrations, particularly in the urban environment, there are responses from various health indicators, from mortality to poor health and hospital admissions, and that as time goes by the studies are more and more precise. We are able to confirm that an increase of a certain PM concentration is accompanied by a precise percentage increase in mortality.
From the methodological point of view regarding short term effects, within a few days of detecting a rise in PM there is also, for example, a rise in the number of deaths, and a range of other effects on health is noted. For the long term effects, comparing different cities with different average values and taking into account all the other known facts, such as socio-economic status or smoking habits, the risk related to the concentration of atmospheric pollutants can be established. We are then able to show that if, for example, in our cities, rather than having an annual average level of 50 micrograms we had one of 20 micrograms, this would lead to a lower health risk of a certain percentage, which can be translated into a corresponding reduction in deaths and other dangerous effects to health.
8220 dead, corresponding to 9% of deaths of those over 30, is a very high figure. Is this 2006 estimate still valid?
It is a substantial number and one that until a few years ago was considered very prudently. However, with the passing of the years this estimate has been confirmed and slightly raised. This information comes from a recent American study. Most of the evaluations on the long term effects of PMs, which are the most worrying, come from American studies based on population groups observed over several years.
The impact estimates for 2002-4 (published in the 2006 report) on Italy are still valid, while those in a study made in 2002, based on the analysis of the concentrations in eight Italian cities, were underestimated.
The same WHO report of 2006 shows that 'Recent knowledge available on the health effects of PM10 allows a breakdown on the cause of death by chronic effects of concentrations over 20 µg/m3 into lung cancer (742 cases per year), infarction (2562) and stroke (329). The numbers are also high for illnesses, including bronchitis, asthma, respiratory symptoms in children and adults, and hospital admissions for cardiac and respiratory diseases that cause the loss of working days'. Although it is easy to attribute an influence on the respiratory system to atmospheric pollution, such a high influence on cardiovascular diseases is more surprising. How is this explained?
The influence on the cardiovascular sphere, due to various physiological mechanisms that are the object of numerous studies, is now a certainty. The fine particles penetrate the circulation system with ease. More cases of death and illness from cardiovascular problems are observed in proportion to an increase in the concentrations of atmospheric pollutants.
The paper also claims that PM increases the risk of respiratory diseases in children, decreases pulmonary function, aggravates asthma and causes other respiratory symptoms such as coughs and infantile bronchitis. What effect is air pollution having on the health of our children?
The relations between air pollution and child health is based on some specific indicators. For example, one of the most important factors is the deterioration in the condition of asthmatics. There is no actual evidence of new cases of asthma, but of a worsening of the symptoms of those already affected, so interactions with already existing conditions are important. Regarding the worsening of the respiratory function with the increase in pollution, a specific analysis was not included in this study, but there are consolidated data to be able to carry out studies today.
The report also mentions hypotheses on the effects on human reproductive outcomes, on spontaneous abortion, on pre-term birth, on foetus size and even on genetic alterations to the embryo. How much do know about this today?
Regarding the influence on the processes of embryo and foetus formation, there are only hypotheses and indications in literature, also at an international level, but these are not confirmed by other indicators. What we are sure of is that air pollution is an important, self-evident risk factor, with considerable and worrying consequences for health. In industrialised countries it is one of the highest environmentally related risks, but this does not mean it is the only important one. We do not yet know enough about how different forms of environmental pollution interact and there is a suspected teratogenic effect concerning some environmental chemical agents.
In the cities of northern Italy and particularly the Po Plain, there are PM10 concentrations of 59µg/m3, which are three times the limit set by Europe (20µg/m3) for 2010 at the time of the WHO report (2006). What effect does this difference have compared to the originally set limits?
European legislation has changed since the time of this report. The limits have been altered and some standards have been raised. Furthermore, they are linked to some time factors both with regard to altering when it comes into effect and the number of subsequent days of acceptable concentrations of PM and other conditions. The case has been much debated. The scientific community has protested at the relaxation of these limits, given the growing evidence, which is, furthermore, mainly produced by studies commissioned by the European Commission itself. The wide range of different interests involved has emerged in the Community debate, which unfortunately have a greater bearing than the scientific evidence.
Is the situation in Italy worse than the rest of Europe?
Italian cities are in the worst band of the 'gradings', but they are accompanied by other European cities. The Po Plain and an area in the Netherlands are among those where the highest concentrations of particles are observed, due to the high polluting emissions and unfavourable meteorological conditions. Nevertheless, we know that some cities in the rest of Europe have achieved a big reduction in the presence of fine particles as a result of policies relating to transport and other sectors.
What difference is there between the cities of north and south Italy?
The estimates on the health impacts, or the number of deaths and pathological cases due to pollution, are proportionate to the size of the population and PM concentrations. At the same population, if the concentration is double, the mortality impact is double. Another established fact is that there is no threshold effect. Even within the limits of the law, regardless of how restrictive, every microgram per cubic metre less is a benefit to health.
There is a marked difference between PM10 concentrations in Trieste and Verona (the latter has more than double, with 61.1, compared to 26.3). How many and which factors is this due to? There would seem to be a reduction in particles in coastal cities (apart from Trieste, Palermo also has lower than average PM levels).
The climate has an important role. It is possible that proximity to the sea and the presence of wind can influence PM concentrations.
Regarding the comparison between different cities, however, we decided to leave this question out of the 2006 study. At the time of the previous report this approach had triggered a fairly pointless debate on the gradings of the best and worst cities, causing the main principle to be lost sight of: to encourage the adoption of comprehensive, wide-ranging policies that would lead to a reduction in PM concentrations.
The harmfulness of PM2.5 seems very relevant, due to the persistence of the particles in the atmosphere and their ease of movement from place to place. How can a credible attribution of the concentrations to the places of study be ensured?
The concentration of PM2.5 is a more precise indication for evaluating the effects of atmospheric pollution on health. As specific survey stations are not yet fully established in Italy, the estimates of PM2.5 used in our studies are based on approximations. In particular, the conversion from PM10 to PM2.5 certainly loses accuracy, but this is not so important. The particles undoubtedly travel a lot and over long distances. But it is also true that we use PM as an overall indicator of air quality and we know that PM2.5 is closely related to local emissions.
Some international studies (EPA Review and ACS American Cancer Society) stress a close link between long term exposure to PM2.5 concentrations and a significant increase in the risk of mortality.
Percentage increases in the risk of death of 6-19% for cardiopulmonary problems, 13% for lung cancer and 8-18% for cardiovascular problems relating to an increase of 10µg/m3 of PM 2.5 are discussed.
How is that 10µg/m3 caused?
Almost all studies on the sources of atmospheric pollution show that traffic contributes 50-60% in an urban environment. Transport is thus the main candidate for possible changes in policy.
Three years after its publication, this data has not aroused any particular reaction or important changes in the policies adopted. Who should be the main recipients of these analyses? Do you not think that doctors have a potential, as mediators of information and with the trust of the public, that goes beyond their current level of involvement?
We often ask ourselves how to give our messages a greater political weight. Doctors certainly have an important role, and some of them are fairly engaged in this. There is, for example, an NGO called 'Doctors for the Environment', which is concerned with precisely this, of sensitising both the professional category and patients. But to have an effect on public opinion and from this on concrete political decisions continues to be difficult.
Is there no legislative mechanism that obliges governments to adopt precise measures to protect the population on the basis of the publication of data by the WHO?
No, the WHO has a solely consultative function by statute. Our partners are the Ministries of Health. The adoption of our guidelines is in the hands of individual governments.
