Atmospheric Pollution in Urban Areas of Greece and Economic Crisis. Trends in air quality and atmospheric pollution data, research and adverse health effects

Ambient air pollution in urban and industrial areas in Greece was a serious environmental problem which was connected with rapid urbanization of cities, anarchic housing development without basic infrastructures and increases of motor vehicle fleet in urban regions. Especially Athens, witnessed severe air pollution problems in the decades 1960s‘-1970s‘ and the formation of the infamous brown-yellow ―nephos‖ in Athens. But in recent years the air quality in Greece has greatly improved in most urban areas because of the better fuels and replacement of the polluting vehicles of old technology. In Athens and Thessaloniki, the ambient levels of coarse smoke, CO, SO2, NOx (NO2, NO), O3 and Pb were reduced substantially below air quality limits. In Athens and Thessaloniki air pollution was characterized by high concentrations of airborne particulate matter (PM) of carbonaceous particles and photochemical smog –which was linked to an excess of nitrogen oxides, hydrocarbons, carbon monoxide (primary pollutants), ozone, and organic nitrates (secondary pollutant) as a result from a series of chemical reactions driven by sunlight. The primary pollution sources were vehicular traffic, central heating, industrial facilities and small enterprises. In the past decades several environmental legislations were undertaken in an effort to improve the existing air quality conditions in urban areas. Replacement of old vehicles (1991), new cars equipped with catalytic converters, replacement of the old buses equipped with anti-pollution devices and natural gas for heating and energy generation was introduced. Environmental legislation was enacted for the abatement of industrial pollution and smoke and energy efficiency measures. Abatement practices reduced substantially primary pollutants (SO2, NOx, CO, smoke) and secondary (O3). The economic crisis of the last five years (2010-2015) affected the prices of heating oil and forced some families to use low-cost wood and biomass as fuel for fire places and stoves (the later dropped in international prices of petrol reduced financial constrains in the use of oil for heating, while the 2014-2015 winter months were mild and air pollution episodes were limited).The result was smoke haze and high levels of airborne particulates (fine and superfine) during the evenings and morning hours of the day in Athens, Thessaloniki and other cities. Airborne particular matter (PM) from burned wood are dangerous because of their toxic organic constituents (polycyclic aromatic hydrocarbons, PAH), free radicals and metals. This review collected some of the most important studies on air pollution in urban areas and the consequences of economic crisis in Athens and other cities. Also, studies on air pollution in areas with lignite-fired power stations were included. Air pollution causes adverse health effects, respiratory diseases (hospitalization), and increased mortality in the last decade (in the years before after the economic crisis). Adverse health effects on urban dwellers in major cities of Europe cities were investigated by multicenter panes of researchers. The results showed that Athens and Thessaloniki have some of the highest levels of air pollutants and PM (PM10, PM2.5). Epidemiological studies in European cities have documented associations between outdoor exposure to air pollutants biomass combustion products and a range of adverse health effects. The present review covers the most important research papers on the air pollution trends in major urban areas, the results of economic crisis in the use of biomass fuel. Also, this review includes studies and investigations for the association of air pollutants (especially PM) with adverse health effects, in particular respiratory diseases, and increased mortality in urban areas.