We have come across the most dangerous man made pollution that can be controlled but we haven’t looked into the control measures. Let us see what are the air control measures in detail by quoting each, even we have discussed it in brief under the topic air pollution.
Air pollution control
The best way to control air pollution is at the source. Emission of pollutants can be reduced by changing to cleaner fuels and processes. In industries many types of air cleaning devices and methods can be used. One method may not be suitable for every pollutant. A combination must be worked upon depending on the type of the pollutant.
Source correction methods
Formation of pollutants can be reduced at the source itself. Those methods which have minimum air pollution potential can be selected for this
- Substitution of raw materials: If the use of a raw material is creating pollutants, alternative raw materials can be sought. For eg Natural gas can substitute traditional high contaminant coal.
- Process modifications: Bringing changes in the processes in order to reduce the pollutant quantity. For eg. If air intake of boiler furnace is adjusted then excess fly ash emissions at power plants can be reduced.
- Modification of existing equipment: Improvements in the design of machinery can reduce the quantity of the pollutants released. For eg. If open hearth furnaces are replaced with controlled basic oxygen furnaces or electric furnaces, smoke carbon monoxide and fumes can be reduced to a great extent.
- Maintenance of equipment: much pollution is caused due to the poor maintenance of the equipment. There can be leakages and these can be reduced by routine checks of ducts, pipes, valves, pumps, seals and gaskets.
- Pollution control equipment: These are used to filter out particulate and gaseous matter.
Controlling emissions from industries
- Common types of equipment for collecting fine particulates include cyclones, scrubbers, electrostatic precipitators, and bag house filters. Once collected, particulates combine together forming agglomerates that can be easily removed from the equipment and disposed off.
- Particulate characteristics that help decide the type of equipment to be used are corrosively, reactivity, shape, density size and size distribution. Other design factors include air stream characteristics such as pressure, temperature, viscosity, flow rate, removable efficiency requirements and allowable resistance to airflow.
- Cyclone collectors are often used to control industrial dust emissions and as pre cleaners for other kinds of collection devices.
- Wet scrubbers are usually applied in the control of flammable or explosive dusts or mists from sources as industrial and chemical processing facilities and hazardous waste incinerators. They can handle hot airstreams and sticky particles.
- Electrostatic precipitators and fabric filter bag houses are often used at power plants.
- Gaseous toxins such as organic volatile compounds and others are controlled by three basic techniques: absorption, adsorption, and incineration. These may be employed singly or in combination. Also a fourth method called carbon sequestration is in development as a means of controlling carbon dioxide levels
- Absorption involves the transfer of a gaseous pollutant from the air into the contacting liquid such as water. The liquid must be able either to serve as a solvent for the pollutant or to capture it by means of a chemical reaction.
- Adsorption is a surface phenomenon. The gas molecules are attracted to and held on the surface of a solid. Gas adsorption is used for odour control at various types of chemical- manufacturing and food processing facilities. Activated carbon or heated charcoal is the most common adsorbent material.
- Incineration or combustion can be used to convert VOCs and other gaseous hydrocarbons to carbon dioxide and water. There are special incinerators called afterburners. Turbulence (mixing), time and temperature are important factors for successful combustion.
- Carbon sequestration is a natural process where carbon dioxide is stored in forests and oceans relying on natural cycles to consume it. Artificial carbon sequestration involves long term storage of carbon dioxide underground, pumping the gas directly into underground geologic reservoir layers. This is a technique that is under development.
Plants contribute towards controlling air pollution by utilizing carbon dioxide and releasing oxygen in the process of photosynthesis. Some plants even fix carbon monoxide and metabolize nitrogen oxides. Planting trees are important in high risk areas of pollution.
Zoning advocates setting aside separate areas for industries so that they are far away from residential areas. Heavy industries should not be located too close to each other. New industries should be established away from larger cities.
Automobiles play a major role in causing air pollution. This is seen more with old diesel vehicles. Newer diesel vehicles meeting stricter limits must be developed. Vehicle exhaust emit nitrogen oxide and particulate matter. These are known to be carcinogenic and are related to respiratory diseases and allergies.
Not only cars and private vehicles, but public buses, trucks, and other auto mobiles including concrete mixers, sanitation vehicles, and refrigerator and freezer vehicles must also be monitored.
Government regulations are in effect in many countries concerning vehicle exhaust. They must also make public transport more appealing so that people are encouraged to use it. Safety measures for travellers especially women, children, and the handicapped must be in place.
Carpooling is in effect in many places especially in the bid to reduce traffic congestion on the overcrowded roads.
Many Asian and European countries have increased cyclists on the road. This method is most accepted in those cities where the regulating authorities have taken the initiative to make dedicated lanes for cyclists. This definitely encourages more people to use alternative methods of transport.
Much research and development is going on in using alternate safer fuels for cars. Many manufacturers are into making electric cars that definitely pollute the environment lesser than diesel or petrol driven vehicles. Biomass is also being considered as a potential internal combustion fuel.
Other Control Measures Taken For Controlling Air Pollution
Constructions And Demolitions
These processes add a large amount of particulate matter to the environment. the material most dreaded is asbestos. The use of asbestos has been decreased drastically in the developed countries. But in developing nations there is still use of asbestos based building materials. It is during uncontrolled demolitions that asbestos is scattered into the atmosphere. Regulations and measures have to enforce to control these activities.
Reducing The Use Of Chloro-Fluoro-Carbons (Cfcs)
The use of aerosols and other solvents containing CFCs have been banned in many countries because these are instrumental in creating the hole in the protective ozone layer and depleting it.
Air Pollution From Land Fills
Locating these as far away as possible from residential areas is mandatory. Recyclable and reusable materials can be segregated much before they reach the landfills. Domestic wastes must be treated before releasing into the ground or water. Untreated sewage is usually disposed openly and lead to pathogen explosion which is turn creates infection epidemics.
Some Control Measures For Indoor Pollution
- Make provisions for proper ventilation
- Ventilate after painting indoors.
- Don’t smoke indoors.
- Don’t mix cleaning fluids. Some chemicals react with each other to form poisonous gases.
- Air the furniture, curtains and carpets regularly.
- Minimize the use of pesticides inside the house
- Fix faulty pipes and maintain dry walls to prevent mould.
- Decide which plants can be used indoors sagely and don’t overwater these.
- Use of air cleaners will help to reduce particulate matter. But it has no effect on gaseous pollutants.
- Minimize the use of air fresheners and scented objects.
Every individual is responsible for the pollution, likewise each are responsible for controlling it. With much effort and many regulations countries like Bhutan, Sweden, Denmark, New Zealand and Canada have kept their pollution indices under check. Even the US has reduced its air pollution levels in 20 years. This can be achieved by collective efforts by starting on a small scale by individuals and climbing up the ladders involving residential associations, municipalities, environmental organisations, corporations and governments. It is a basic human right – Clean and fresh air for everyone.