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Air pollution in Athens: existing status and abatement practices

In Athens, two types of air pollution are recognized: the first is characterized by high concentrations of particles. The second type - photochemical smog - is linked to an excess of nitrogen oxides, hydrocarbons, carbon monoxide (primary pollutants), ozone, and organic nitrates (secondary pollutant) and results from a series of chemical reactions driven by sunlight.

Athens' ColiséeSeveral measures have been taken or are in the process of implementation, in an effort to improve the existing air quality conditions in the city.
A retirement plan for old vehicles was introduced in 1991 in an effort to renew the motor vehicles fleet with new cars equipped with catalytic converters. [The measure was of nationwide coverage, lasted for two years (1991-1992) and resulted in 260,000 old cars to be retired in Greece, of which 150,000 cars in Athens].
The national inspection programme for the control of emissions from motor vehicles was initiated in 1994, consisting of regular inspections of all private vehicles once per year and taxis and light trucks twice per year.

Expansion of the subway system. At present two new lines of a total length of 18 km are constructed. The project is expected to conclude in the year 2000. It is anticipated that daily automobile trips in the centre of the city will be reduced by 250,000 trips.

A project for the full replacement of the old buses with new ones equipped with anti-pollution devices has been initiated.

In addition to the replacement of buses, several other measures are taken in an effort to make public transport attractive to Athenians.

  1. Rescheduling of bus routes to accommodate distant neighbourhoods or to link neighbourhoods by means of efficient routing.
  2. Dedicated bus lanes to improve running conditions. According to relevant measurements, the introduction of bus lanes has resulted in the increase of the average hourly speed of a bus from 16 km/h to 30 km/h.

The odd-even traffic regulation system. According to the system, cars with plates ending in odd numbers can circulate in the centre of Athens on odd days, whereas cars with plates ending in even numbers can circulate on even days.

From 1995 traffic of all types of motor vehicles (including taxis and motorcycles, but excluding public buses) was banned from the commercial centre of Athens.

In the event that meteorological conditions for the following day may lead to pollution concentration, full banning of traffic is applied in the centre of Athens.

In an effort to reduce traffic, the working schedule of public and private employees were modified during the summer months of 1994-1996. Employees were divided into four major categories with different start and completion times.

Contribution (%) of various pollution sources to the photochemical pollution of Athens
  Motor Vehicles Domestic Heating Industry

Nitrogen oxides


Carbon monoxide

Sulphur dioxide
















A number of significant measures for the improvement of air quality were introduced in 1994 and 1995, in particular:

  1. The content of sulphur in heavy fuels was reduced from 0.3% per weight to 0.2% per weight.
  2. From 1/1/1995, the content of sulphur in unleaded gas was reduced from 0.10% per weight to 0.05% per weight.
  3. The content of benzene in gasoline was reduced from 5% per volume to 4% per volume.
  4. Introduction of natural gas at around 15% of the energy balance in Athens by the year 2000 (households and industrial units).

As a result of the abatement practices, the level of sulphur dioxide, smoke, nitrogen dioxide and ozone exhibit a gradual decrease in later years. However, the exceeding of the levels of the World Health Organization are still recognized in a higher frequency in the city centre, with the exception of zone which exhibits its higher values in the northern suburbs of Athens. It is anticipated that the completion of the major infrastructural works in Athens (e.g. Metro, peripheral roads, introduction of natural gas, replacement of buses, etc.) will decrease to a considerable extent current atmospheric pollution levels.


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