Air Quality

Scenarios

Air pollution has emerged as one of the most serious environmental problems in Bangladesh in recent years. With unplanned urbanization and rapid vehicular growth, air quality in major cities of Bangladesh is deteriorating fast. But until recently, the government and environmental groups didn't pay much attention to the declining air quality of Bangladesh. From the late 1990s, air pollution has become  a major concern for the inhabitants of Dhaka, one of the most densely populated cities of the world. When scientists from Bangladesh Atomic Energy Commission revealed in 1996 that the level of lead pollution in the air of Dhaka was the highest in the world, people got panicked and environmental groups began their outcry against the government for its inaction. The issue was ultimately raised in the parliament with several MPs calling for immediate action to lower the level of air pollution in Dhaka.

Industries and motorized vehicles  are the two major sources of urban air pollution  in Bangladesh. The pollutants that have been as found out so far in the air of the country are dust particles, sulphur dioxide, oxides of nitrogen,  hydrocarbon, carbon monoxide, lead and ammonia.

Dhaka: One of the Worst Polluted Cities in the World

The population of Dhaka is now close to 10 million. In 1950 only 430,000 people inhabited Dhaka. Every year more people from rural areas are migrating to this mega-city seeking employment. The number of vehicles, industries and factories are multiplying rapidly with the rapid expansion of the city coupled with increasing population. In order to accommodate the growing population, multi-storied buildings are being built more than ever. The tremendous pressure of population has made it almost impossible to maintain a clean environment in the capital.

The air pollution survey of 1990 found that industries located in and around Dhaka were not the main source of air pollution. The main sources of air pollution in Dhaka were the vehicles and the brick fields built around the outskirts of the capital. The survey recorded the highest level of Suspended Particulate Matter (SPM) in the air of Dhaka at 570 micrograms per cubic meter. At several points in Mirpur, Tejgaon, Lalmatia, National Press Club and Mohakhali the SPM level was more than 100 micrograms per cubic meter. SPM level in the air of Dhaka was the highest during the low rainfall period of January- February-March. However it comes down to less than 100 micrograms per cubic meter in the high rainfall period of August-September-October.

In January 1990, sulphur dioxide was measured at 312 and 359 micrograms respectively in the air of Motijheel and Tejgaon of Dhaka. The highest amount of the oxides of nitrogen was 54 miicrograms per cubic meter (at Motijheel).

The Department of Environment (DoE) surveyed the condition of atmosphere in February and March of 1996 at Lalmatia, Gulistan, Motijheel, Paltan, Asad Gate and Farmgate. According to the survey report the state of air pollution in Dhaka was "alarming". The report stated that the amount of suspended particulate matter (SPM) and sulphur dioxide were increasing in Dhaka's air. Both shot up much more than the highest acceptable level. In the survey the highest level of SPM was found, 1773 micrograms per cubic meter, at Farmgate of Dhaka. At Asad gate and Tejgaon, level of SPM was recorded at 1438 and 729 micrograms respectively. The acceptable SPM standard in the industrial and mixed area is 500 micrograms per cubic meter; for commercial and mixed areas it is 400; for residential and rural areas 200; and for sensitive areas it is 100. A study conducted by a group of scientists from Bangladesh Atomic Energy Commission found that lead pollution in the air of Dhaka was highest in the world. According to their findings the level of lead pollution in the air of Dhaka was 463 nanograms (one nanogram is equal to one billion of a gram).

Air Pollution in Dhaka (Monthly Average Data)

Air Pollution in Chittagong

Chittagong is the second largest city of the country with an estimated population of four million. Although air pollution in Chittagong is not as bad as Dhaka, the situation is deteriorating rapidly. Like Dhaka, Chittagong too does not have a systematic mass transport system. Rickshaws, three wheelers, a few buses are the main means of transport for the ordinary people.

At present, the city has 80,000 automobiles.  According to traffic police officials, a third of these vehicles do not have any fitness certificate. The old and junk vehicles are many, and the black smoke emitted from these vehicles is one main source of air pollution. The greenery around Chittagong City helps to refresh the polluted air. But destruction of green hills in and around the city is a big threat to the environment. The vegetation of the city is disappearing fast exposing the city to yet more severe air pollution.

There are certain areas where the level of air pollution is presumably higher than some other parts of the city. Air quality is the worst in the city's business district Agrabad and in Anderkilla, the older part of the city.

No up-to-date data about the state of air pollution in Chittagong is available. However, the Department of Environment conducted a study at Sirajuddaula Road of the city in March, 1990. According to that study, the amount of SPM was 54 and 86 respectively on March 24 and 25 in 1990. The amount of Sulphur dioxide and, the oxides of nitrogen in the air were 572 and 756  micrograms per cubic meter respectively.

The highest acceptable level of the oxides of  Sulphur and nitrogen in the air is 100 micrograms  per cubic meter, a standard set by the DoE. As the he survey revealed, these harmful elements were  five times higher than the acceptable level in the air of Chittagong in 1990. Experts say, over the last eleven years, the quality of air in Chittagong deteriorated further.

Air Pollution in Chittagong

Air Pollution in Bogra

In Bogra, the main industrial town of North Bengal, motorized vehicles and industries are air the main sources of air pollution. Population of Bogra town is now close to 150,000. There are 3,000 small and big factories in the town (including the cottage industries). Of them 1,000 factories can be labeled as polluting industries. Besides, there are 2,000 motorized vehicles, which also contribute to the town's air pollution. In the winter of 1996 the Suspended Particulate Matter (SPM) in the air of Bogra town was measured at 732 micrograms per cubic meter. Industries that are largely responsible for the air pollution in Bogra are: Tajma Ceramics, Bogra Cotton Mills (presently closed), Habib Match Factory, Jahid Metal Industry, Bhandari Iron Works, Tajma Enamel, Doctor's Chemical, Essential Drug Co., Sipla Ltd., Konok Textiles, Bogra Tannery, Firoj Soap Factory, Nurani Bread and Biscuit, Bashar Metal, Bogra Motors, Ilora Textiles Industries, Sabuj Oil Mill, KK Twisting Industries,SharifBidi,JamilBidl, Virginia Tobacco idul Haque (presently closed) and Jamil Soap Factory.
 

Pollution Sources

Air Pollution Caused by  Smoke from Vehicles

One main source of air pollution in big cities of Bangladesh like Dhaka is the smoke emitted from the automobiles. With the rapid expansion of the city, the number of motorized vehicles is increasing every year. The total registered automobiles in Dhaka are more than 200,000. In 1971 the total automobiles were merely 36,000.

Ninety per cent of the automobiles in Bangladesh lack proper fitness to ply the streets. The reasons are manifold: lack of proper servicing of the vehicles, import of old vehicles, poor condition of roads, corruption in issuance of fitness certificate and use of excess sulphur and lead in the fules. In 1988, the DoE had conducted a survey on 99,757 automobiles. Among these, 13,308 were found to be polluting the air. The situation has not improved over the last twelve years.

Air Pollution Caused by Industries

Bangladesh is still at its initial phase of industrialization. But it does not mean that the risk of air pollution is less here. Bangladesh is the world's most densely populated country, , which means if pollution occurs at any place by even one polluting agent, a big population remain at the risk of being exposed to it.
At the moment, the country has 30,000 industrial units of which 24,000 rank among the cottage industry. The main industries of the country can be divided into two categories based on renewable local resources and non-renewable local resources. Industries based on renewable
local resources are jute, pulp, paper, match, sugar, tobacco, leather, salt and other agro-based industries. Examples of industries based on non- renewable local resources are the natural gas based industries, ceramic industries, brickfields, etc.
A large number of industries in Bangladesh are not located in proper places. Many hazardous and polluting industries are located near residential areas. The air adjacent to a factory is usually contaminated by the poisonous gases and dust which emit from the industrial units. Mercaptan chlorine is emitted from the pulp and paper mills. Urea fertilizer factories emit urea dust and ammonia gas. A TSP [fertilizer] plant pours out a huge quantity of dust-20 MT of dust a day on average.

Among all the industries, jute mills are the worst. One per cent of all raw materials used in the jute mills is thrown into the air as dust and waste. Workers of jute mills suffer from respiratory problems due to their long hours of exposure to polluted air.

In almost every town in Bangladesh, welding factories, oil mills, pulse factories are located close to residential areas; engineering workshops are often found adjacent to educational institutions.

In the Tejgaon industrial area of Dhaka, Faruk Chemical Industries is located close to Nabisco Biscuit Factory. There is a heavy metal industry adjacent to Polar Ice Cream Factory. Kohinoor chemicals factory is located near Haque Biscuits Factory.

In parts of old Dhaka, the most densely populated areas of the city, hundreds of legal and illegal welding factories are at work. Carbon monoxide gas emits from these factories during welding. There are many small factories in Dholaikhal, Moishundi, Sutrapur, Rokonpur, Gandaria, Narinda, Najimuddin Road, Tipu Sultan Road, Hajaribagh, etc. Most of the factories built in the residential areas are illegal. Smoke and stench radiating from these factories have made life difficult for the local inhabitants.

In Chittagong there are 144 polluting industries located in different industrial areas. Among these are 19 tanneries, 26 garment industries, one oil refinery ,one DDT (now closed) factory, two chemical factories, five fish processing industries, two cement, one paper and rayon, two steel, two soap, two pesticide, four dye manufacturing factories and 75 other small industries.

Most industries in Bangladesh do not have any waste recycling plant or system, which is simply essential for any industry discharging pollutant.


Air Pollution Caused by the Brick Fields

Brick is one major building material in Bangladesh Use of concrete is very limited and most of thehouses are built with bricks. A huge supply  bricks comes from the brick fields. The brick field are developed with the permission of Tariff and Excise Department and Department of Environment. Most of the brick fields around the country are situated near the urban areas. According to the DoE one major reason of the increasing level of Suspended Particulate Matter (SPM) is the dust thrown into the air from the brick fields.

Brick fields require quality soil. The kilns art usually built in cultivable land. Most brick field use firewood; a small number of brick fields use natural gas though. Brick fields discharge a lot of smoke, dust and ashes which spread out around quite a large area near the fields. The people living in the areas adjacent to the brick fields are always al the risk of being affected by respiratory problems. The thick layer of dust on the leaves of crops and trees bars the photosynthesis process, which may destroy the vegetation if continued for a long time.