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| Air
Pollution And Human Health |
Sulphur dioxide (SO2 ) is a colourless gas readily soluble in water. Natural sources such as sulphur bacteria activities, volcanoes, forest fires etc. contribute to environmental levels of SO2. Man made contributions include the use of sulphur containing fossil fuels for transportation, domestic purposes and power generation. Of greater interest, with respect of outdoor air quality are the effects on health, of the lower concentration to which human beings may be exposed in the ambient air. The effects have been studied in a number of different ways, including exposure of volunteers to sulphur dioxide in the air, which they breath and by examination of effects on members of the population who have been exposed to episodes of atmospheric pollution.
Sulphur dioxide causes its irritant effects by stimulating nerves in the lining of the nose, throat and the lung airways. This later affects the people suffering from asthma and chronic lung disease, whose airways get inflamed and easily irritated. Studies of normal healthy volunteers, exposed to sulphur dioxide in chambers have shown that measurable narrowing of the airways may occur after breathing the gas for 5 minutes at concentration of 4-5 ppm but the effects were not detectable at concentrations below 1 ppm. The most common acute exposure to SO2 concentration ³ 0.4 ppm is indication of broncho-constriction in asthmatics after exposure lasting only 5 minutes. The effects of SO2 on airway of asthmatics are reversible with recovery occurring within one hour. Exposure at lower levels can cause increased upper respiratory symptoms such as cough, sore throat and changes in lung function. The morbidity effects are associated with long-term exposure to particulates and or sulphur dioxide. The acidic aerosols composed of particulate matter and acids cause inflammation of airways and lungs and reduce the ability of small airways to clear mucous and particles. The health morbidity indices are lung function decrement, upper and lower respiratory disease symptoms, increase in rates for cough, bronchitis and other health problems.
Table 4 Summary of Health Effects of Basic Air Pollutants
| Pollutant |
Health Effects |
|
Carbon Monoxide | Poor reflexes |
| Ringing in the ears | |
| Headache | |
| Dizziness | |
| Nausea | |
|
Breathing Difficulties | |
|
Drowsiness | |
| Reduced work capacity | |
| Comatose state (can lead to death) | |
|
Lead (Pb) | Kidney Damage |
| Reproductive system damage | |
| Nervous system damage (including brain dysfunction and altered neurophysical behaviours) | |
| Oxides of Nitrogen (NOX ) | Increased risk of viral infections |
| Lung irritation (including pulmonary fibrosis and emphysema) | |
|
Higher respiratory illness rates | |
|
Airway resistance | |
|
Chest tightness and discomfort | |
|
Eye burning | |
|
Headache | |
|
Ozone (O3 ) |
Respiratory system damage (lung damage from free radicals) |
| Reduces mental activity | |
| Damage to cell lining (especially in nasal passage) | |
| Reduces effectiveness of the immune system | |
|
Headache | |
| Eye irritation | |
| Chest discomfort | |
| Breathing difficulties | |
| Chronic lung diseases ( including asthma and emphysema) | |
|
Nausea | |
|
Sulphur dioxide (SO2) |
Aggravates heart and lung diseases |
|
Increases the risk for respiratory illness (including chronic bronchitis, asthma, pulmonary emphysema) | |
|
Cancer ( may not show for decades after exposure) | |
| Respirable Particulate Matter (PM10 ) | Respiratory illness (including chronic bronchitis, increased asthma attacks, pulmonary emphysema) |
| Aggravates heart disease |
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