As if the more well-known problems of air pollution in Athens (such as sulphur dioxide, ozone and carbon monoxide) were not enough, research is emerging regarding the effects of PM10, which is very small particulate matter (with a diameter of less than 100 micrometers) consisting of hydrocarbons, microscopic particles of carbon, inorganic and organic substances, which are emitted chiefly from vehicles. These particles are responsible for a number of diseases, mostly of the respiratory tract, and increased deaths around the globe. Scientific research programs in Europe and the US are attempting to determine all the parameters involved and the effects of this airborne particulate matter on public health. According to Polyxeni Nikolopoulou-Stamati, associate professor in environmental pathology at Athens University’s medical faculty, who heads the research program «Awareness-Raising about Environment and Health of Non-Expert Advisers» (www.di.uoa.gr) into the effects on health from environmental pollution in 11 European states, PM10 is responsible for many irreversible conditions in the lungs, heart, bone marrow and nervous system. «The respiratory passages that carry the air we breathe are the nose, the nasopharynx, the trachea, the bronchi and the alveoli, all of which are made in such a way as to create a barrier between the air and the body,» she explained. «That barrier is formed by the close linking of the cells, whose surface consists of fine fringes which, with the help of coughing and sneezing, work to eject anything undesirable entering these oxygen passageways. What the airborne particles do is destroy the natural barrier in the respiratory passageways and get in between the cells, and deactivate the fringes, thereby arriving at the terminal points of the lungs, the alveoli, where oxygen is exchanged with carbon dioxide, or else they penetrate the destroyed cell barriers and thereby enter the bloodstream.» When the airborne particles reach the alveoli they encounter a macrophage, which tries to annihilate anything recognized as dangerous for the body. However, despite these efforts, an irreversible process is put in motion, in which substances are freed that predispose the body to inflammation and the destruction of the lung. If they manage to penetrate the cell barriers and enter the bloodstream, then they reach the heart, causing cell destruction in the myocardium and the nervous system. PM10 is not a recent phenomenon. It has always been in the atmosphere we breathe but did not include the categories of pollutants measured by special equipment until 2000, when the first official measurements of dangerous pollutants began. High concentrations in Attica In the most recent report by the Environmental Protection Service (PERPA) for 2001, the data for Attica are by no means reassuring; the average concentration of PM10 ranged from 30.8 to 59.7 mg/per cubic meter, when the annual limit for 2001 had been set at 46.4 mg/cubic meter. High concentrations, which should not be found on more than 35 days a year, were found over 93 days (in some cases, such as in Lykovryssi, these reached over 70 mg/cubic meters). The European Union directive on the issue has established a limit of 40 mg/cubic meter by 2005, but according to the World Health Organization, even concentrations of 10 mg/cubic meter are dangerous. In Athens, measurements of airborne particles began in 2000 and since last October, results recorded at stations around Attica have been included in PERPA’s List of Atmospheric Pollution Levels. In Thessaloniki, the municipality has been taking measurements for the past 10 years. The Environment and Public Works Ministry is considering setting up measuring stations in other regional centers as well. These particles are emitted mainly in vehicle exhaust fumes, but this is not the only source. They are also released into the atmosphere from the use of natural gas, propane flames, and even cigarette smoke. Concentrations vary from place to place, as airborne particles are also produced naturally, but their spread depends on the morphology and composition of the soil, as well as the climate. Last summer, Environment and Public Works Minister Vasso Papandreou announced measures, in cooperation with the Finance and Transport ministries, regarding restrictions on pollutants from vehicles (including tire friction on asphalt and diesel engines), central heating, transport and industry. Sources of airborne particles can also be natural, chiefly the air currents bringing dust from the Sahara and the particles brought into the city from areas in Attica denuded of trees. The problem is complex, as are the causes, and are likely to be a matter of concern for years to come. The question which comes to mind is that of other unknown pollutants (of the PM10 type) which, if they do exist and we are inhaling them, are not being measured despite the fact that they are affecting the health of humans and animals and being absorbed by plants.