2. Rationale for the Reduction of SO2 and Particulate Air Pollution

  Good air quality is a prerequisite for the sound health and well-being of humans and ecosystems. Polluted air not only affects human health, ecosystems and materials in a variety of ways, but also transports the pollution across long distances and across different media (land and water). The health effects from exposure to air pollution can include: irritation and annoyance, loss of organ functions (e.g. reduced lung capacity), morbidity and mortality. Some effects can be acute and reversible, while others develop gradually into irreversible chronic conditions. The respiratory system and the eyes are the main organs affected by air pollution.

2.1 Health impacts of SO2 and particulate air pollution
  Considerable attention has been given in recent years to epidemiological studies and research into the health effects of ambient air pollution. Studies have covered different acute and chronic health effects which occur as a result of particulate matter and SO2 pollution.
Linking Pollution and Health In a number of cases it has been confirmed that the prevalence of persistent coughing and phlegm is significantly related to air pollution including that arising from SO2 and NOx. Various statistical analyses have reported on the relationship between the prevalence of chronic bronchitis and SO2 and NOx air concentrations. In polluted areas the prevalence of persistent coughing and phlegm is 2-3 times higher than in areas where pollution is less extensive. Such a relationship is also derived for areas where mortality results from lung cancer. A relationship between air pollution and respiratory diseases has been proved in Hungary and Bulgaria (see Box 1 and 2), while statistical analysis of medical insurance records in countries with polluted areas, and the associated costs of medical treatment, has also been used to indicate the existence of adverse health effects.

BOX 1: Health Effects of SO2 and Suspended Particulates in Hungary

Acute respiratory diseases are known to be the cause of between 23 and 25 percent of all sick-leave cases in Hungary. A clear relationship between the prevalence of the disease and the levels of SO2 and suspended particles has been verified by epidemiological studies carried out among school children. Among all acute respiratory diseases, catarrh in the lower respiratory tract (e.g. bronchitis, pneumonia) warrants particular attention, since it can significantly affect future health status. High levels of SO2 and particulates can increase the occurrence of asthma, in particular among children. A similar tendency is observed with regard to lung cancer. In 1994, 3.2 percent of deaths in Hungary was traced to chronic respiratory diseases. The rate is comparatively constant. Prognosis and therapy for such diseases can be effective but costly. Country-wide surveys of the prevalence of these diseases are recommended.

BOX 2: Health Effects of SO2 Emissions and Particulates in Bulgaria

Urban population constitutes around 30-32 percent of the total population of Bulgaria. The inhabitants of these cities are endangered by SO2 and particulate pollution. The respiratory tract tends to be most often affected and the most significant problem in both the country as a whole, and in particular among its cities.

Average annual SO2 concentrations vary a great deal in Bulgaria depending on location, from accepted safety limits to levels with dangerous health implications. Among the most polluted regions in Bulgaria are Asenovgrad, Dimitrovgrad, Kardjali, Pernik, Zlatitsa and Pirdop. Health problems are complicated by the fact that in those regions with high concentrations of SO2, the concentration of particulates is also high. Such regions where the synergetic effect of both pollutants occurs are Kardjali, Pirdop-Zlatitsa, and Dimitrovgrad.

The diseases of the respiratory system most frequently occur in cities with high levels of pollution from chemical and cement industries, such as Devnia, Dimitrovgrad and Vratsa. In some cities (for example, Dimitrovgrad, Devnia, Vratsa, Kremikovtsi) the occurrence of pneumonia is significantly higher than the country average and is expected to further increase. Chronic respiratory diseases (including sinusitis, pharingyitis, bronchitis, and laryngitis) are commonly high in cities with chemical industries and refineries (such as Devnya, Bourgas and Stara Zagora), as well as in regions with non-ferrous industries (including Kardjali, Plovdiv, Asenovgrad, Zlatitsa, Eliseina). In cities where highly developed chemical industries are found (Devnia, Bourgas, Vratsa and Rousse), bronchial asthma can be observed with higher frequency. The number suffering from asthmatic disorders is particularly high in Devnia - exceeding the country average by more than double. A relationship between abnormal psycho-neurological development and air pollution, as well as poor lung activity and the retarded growth of children has been recorded in Dimitrovgrad. High levels of particulates resulting in neurological and psychological diseases with continuous impact on the mental ability of children has been found in Plovdiv, Asenovgrad, Kuklen, Kardjali and Pernik.

Source: National Report on the Reduction of Emissions of SO2 and Particulates in the Republic of Bulgaria

Combined Effect The situation is further worsened by a similar occurrence resulting from concentrations of particulate matter. It should be emphasized that SO2 and particulates act synergetically. Thus particulates carry SO2 to the lower part of the respiratory system which would not otherwise be reached (SO2 would normally be absorbed by the walls of the upper respiratory tract). Chemical reactions between SO2 and particulate matter can form new compounds such as sulfuric acid and ammonium bisulfate, known as acidic aerosols. The human health effects of these compounds include bronchospasms in asthmatics (caused by acute exposure), and acute and chronic bronchitis (caused by chronic or cumulative exposure). SO2 is the precursor of sulfate particulates which can irritate eyes and the respiratory tract, reduce lung function, aggravate emphysema, asthma, and chronic bronchitis and may result in mortality.
Particulates Particulate matter can lead to pulmonary irritation and respiratory diseases. It must be pointed out, however, that the effects of particulate matter vary considerably since it tends to be composed of many different substances of varying sizes and quantities that can be potentially carcinogenic and mutagenic. Elemental carbon, polyaromatic hydrocarbons (PAHs) and toxic base metals are among the constituents of particular matter of greater importance with regard to human health.

Particulates originate from a variety of mobile and stationary sources, and vary in terms of physical composition, chemical content, and size. The most harmful to human health tend to be small particulates, owing to their ability to reach the lower regions of the respiratory tract and contribute to the negative effects on breathing and respiratory systems, aggravation of existing respiratory and cardiovascular diseases, anomalies in the body's defense systems to foreign substances, damage to lung tissues, carcinogenesis and premature death. As a result of these linkages particulates with diameter of 10 micrometers and lower have begun to be regulated. In the US, for example, the focus has shifted to particulate matter (PM) of 2.5 micron diameter and smaller. This results in a very different set of control measures compared with those for total suspended particulates (TSP). While SILAQ countries adhere to EU norms, the EU will almost inevitably be moving toward regulating even smaller particles, and thus when investing in control devices in the SILAQ countries, this should also be kept in mind.
EU Trend The studies and methods used in assessing health effects, developed in the US, the EU and elsewhere, can be adapted for the SILAQ countries. Levels of exposure throughout these countries need to be defined since the available data collected from the questionnaire surveys is insufficient. Further studies might therefore take place.

Finally, it should be mentioned that aside from the health risks associated with the inhalation of gases and particles, there are also significant economic consequences arising from SO2 and particulate pollution. These include deforestation, acidification of water bodies and soil, and the accelerated deterioration of building materials, including historical monuments and buildings.

REC * PUBLICATIONS * REDUCTION OF SO2 AND PARTICULATE EMISSIONS * RATIONALE

PREVIOUS NEXT COVER PAGE HOME PAGE