Sources and health effects of air pollution

Sources and health effects of air pollution
Pollutants	Sources	Health Effects
Nitrogen dioxide	All combustion processes (for example road vehicles and domestic heating) produce oxides of nitrogen (NOx) which particularly in the presence of ozone is converted into nitrogen dioxide.	General irritation to airways including increased chance of respiratory infection and impaired lung function.
Primary Particulates	Road traffic (for example diesel engines, brake and tyre wear); industrial sources (for example power stations).	Respiratory and cardiovascular problems. Concerns about long-term effects.
Secondary Particulates (e.g. sulphates, nitrates)	Formed through the oxidation (presence of ozone) of particular gases (for example sulphur dioxide, nitrogen dioxide) in the atmosphere condensing to form fine particles.	Respiratory and cardiovascular problems. Concerns about long-term effects.
Carbon monoxide	Road transport and industry (all combustion of carbon based fuels).	Reduces the oxygen carrying capacity of blood and at low levels reduces concentration and at higher levels causes headaches, nausea, dizziness. At very high levels it can lead to death.
Sulphur dioxide	Combustion of fossil fuels (mainly coal and heavy oils).	Causes breathing difficulties, and irritation of the eyes, nose, throat and lungs. People suffering from asthma are particularly susceptible.
Lead	Petrol and industry (such as smelting, and paint works).	Can effect the intellectual development of children, and at very high doses poisoning, brain and organ damage can occur.
Benzene	Combustion and distribution of petrol.	Exposure over a long time can lead to cancer.
1, 3 Butadiene	Combustion of petrol and diesel, and the production of rubber for tyres.	Exposure over a long time can lead to cancer.
Ozone	Ozone is a photochemical pollutant which means it is primarily formed by the reactions of other pollutants such as nitrogen oxides in the presence of sunlight.	Exposure can cause an irritant effect on the lungs, airway inflammation and short term respiratory symptoms.