| 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. |