Prevention and Control of Air Pollution from Park's Textbook of Preventive and Social Medicine
Reading File
Finding Sources
Finding Sources
Reading File
Finding Sources
Reading File
Reading File
I now have all the content needed for a thorough answer. Here is the complete, well-organized response from Park's Textbook.
Prevention and Control of Air Pollution
Park's Textbook of Preventive and Social Medicine (p. 839)
Core Principle
The control of air pollution is ultimately an engineering problem. WHO has recommended a structured set of procedures for its prevention and control.
WHO-Recommended Procedures
(a) Containment
Prevention of the escape of toxic substances into the ambient air. This can be achieved by a variety of engineering methods:
- Enclosure - physically sealing emission sources
- Ventilation - directing polluted air away from inhabited spaces
- Air cleaning - using filters and "arresters" designed to remove contaminants before release
A major contribution in this field has been the development of "arresters" for the removal of contaminants at source.
(b) Replacement
Replacing a technological process that causes air pollution with one that does not. Key examples include:
- Increased use of electricity, solar power, natural gas, and central heating in place of coal - this has greatly helped in smoke reduction
- De-leading of petrol - there is a global move to reduce lead in petrol (a cumulative poison); India has also adopted de-leaded petrol
(c) Dilution
Dilution is valid so long as it remains within the self-cleaning capacity of the environment. Examples:
- Some air pollutants are readily absorbed and removed by vegetation
- Establishment of "green belts" between industrial and residential areas is an attempt at dilution
- The capacity for dilution is limited - problems occur when the atmosphere is overburdened with pollutants
(d) Legislation
Air pollution is controlled in many countries by suitable legislation. Coverage includes:
- Height of chimneys
- Powers to local authorities to carry out investigations, research, and education
- Creation of smokeless zones
- Enforcement of standards for ambient air quality
- Example legislation: Clean Air Acts (various countries)
In India: To decrease the nuisance of air pollution, the Government of India enacted "The Air (Prevention and Control of Pollution) Act" in 1981.
(e) International Action
To deal with air pollution on a worldwide scale, WHO has established an international network of laboratories for the monitoring and study of air pollution. This network consists of:
- Two international centres at London and Washington
- Three regional centres at Moscow, Nagpur, and Tokyo
- 20 laboratories in various parts of the world
These centres issue warnings of air pollution where and when necessary.
Monitoring of Air Pollution
The best indicators of air pollution are sulphur dioxide, smoke, and suspended particles, monitored daily over several sites with results collected by a central agency.
| Method | Description |
|---|---|
| Sulphur dioxide | Major contaminant in urban/industrial areas; estimated in all surveys |
| Smoke/Soiling index | Air filtered through white filter paper; stain measured by photoelectric meter; expressed as micrograms/cubic metre |
| Grit and dust measurement | Deposit gauges collect solids; analyzed monthly |
| Coefficient of haze | Used especially in the USA; assesses amount of smoke/aerosol in air |
| Air pollution index | Arbitrary index accounting for one or more pollutants |
Disinfection of Air (Related Measure)
Methods employed for air disinfection include:
- Mechanical ventilation - reduces vitiated air and bacterial density
- Ultraviolet radiation - effective in special situations (operation theatres, infectious disease wards); UV lamps are shaded and placed in the upper portion of rooms near air inlets to protect eyes and skin; proved effective in public assembly halls and school rooms
- Chemical mists - Triethylene glycol vapours are effective air bactericides, particularly against droplet nuclei and dust
- Dust control - Application of oil to floors of hospital wards reduces bacterial content of air
Note: Air disinfection is still largely in the experimental stage.
Major Air Pollutants - Quick Reference (Table 3 from Park's)
| Noxious Agent | Sources | Adverse Effects |
|---|---|---|
| Oxides of nitrogen | Automobile exhaust, gas stoves/heaters, wood-burning stoves | Respiratory irritation, bronchial hyperactivity, impaired lung defences, bronchiolitis obliterans |
| Hydrocarbons | Automobile exhaust, cigarette smoke | Lung cancer |
| Ozone | Automobile exhaust, high-altitude aircraft cabins | Cough, substernal discomfort, bronchoconstriction, decreased exercise performance |
| Sulphur dioxide | Power plants, smelters, oil refineries, kerosene heaters | Exacerbation of asthma and COPD, respiratory irritation, death in severe exposure |
| Lead | Automobile exhaust using leaded gasoline | Impaired neuropsychological development in children |
Key Points to Remember
- Air pollution damages the respiratory and cardiorespiratory system
- Most vulnerable groups: elderly, children, smokers, and those with chronic respiratory disease
- Achievable reductions in urban air pollution can prevent 5% of all infections and chronic respiratory diseases, averting 0.6% of the global burden of disease
- Epidemiological studies show that a sudden increase in air pollution is often associated with an immediate increase in morbidity and mortality
- Social/economic effects include: destruction of plant and animal life, corrosion of metals, damage to buildings, reduced visibility, and soiling of clothing
Park's Textbook of Preventive and Social Medicine, p. 839 - "Prevention and control of air pollution"
This is a shared conversation. Sign in to Orris to start your own chat.