According to the European Environment Agency the major contributors to air pollution in Europe are:
- Power generation [SO2 and NOX];
- Transport [NOX, CO, PM2.5, and PM10]; and
- Agriculture [NH3].
However in Malta, road transport is the major contributor to air pollution in urban areas. High levels of particulate matter (PM10 and PM2.5) and of nitrogen oxides (NOX) are normally associated with areas exposed to heavy traffic flows. In rural areas, away from anthropogenic sources, levels of ozone (O3) are the chief air quality concern.
As far as the regulated air pollutants are concerned the following are considered to be the major sources:
Particulate Matter Fuel Combustion in Power Generation.
Fuel Combustion in Road Transport
Tyre and brake wear
Ozone Is not emitted directly but results from reactions involving precursor gases such as volatile organic compounds and nitrogen oxides.
Nitrogen Oxides (NO and NO2) Combustion Sources (results in NO mostly, which is subsequently oxidized to NO2).
Sulphur Dioxide (SO2) Combustion of fuels containing high levels of sulphur (e.g. Heavy Fuel Oil in thermal power plants).
Benzo[a-]pyrene Incomplete combustion of fuels in road transport and rubber-tyre wear.
Carbon monoxide Incomplete combustion of fuels in road transport.
Benzene Incomplete combustion of fuel in road transport.
Handling and distribution of petrol.
Arsenic Metal smelters.
Cadmium Non-ferrous metal production.
Iron and steel production
Stationary combustion of fossil fuel.
Nickel Combustion of fuel oil and coal in stationary plants.
Combustion of fuel in ships.
Lead Combustion of fossil fuel.
Production of non-ferrous metals.
Production of iron and steel.
Production of cement.
Mercury Combustion of coal.
According to the WHO, cardiovascular disease is the most common reason for premature death as a result of poor air quality; lung diseases (including lung cancer) follow. Air pollution is not only the cause of premature mortality, but is also known to increase the incidence of various diseases.
The diagram below summarises the major health effects of air pollution. A more detailed description on the health effects of particulate matter, nitrogen dioxide, sulphur dioxide and ozone can be obtained from the following document.