Dr. M Abul Kashem Mozumder & Dr. Md. Shairul Mashreque :
One of the worst cases of air pollution is Dhaka, the capital city of Bangladesh. India’s Delhi is the worst. The Dhaka dwellers are experiencing many health effects of worst air. People, especially children, adults and women suffering from respiratory diseases are advised to avoid outdoor activities while everyone else is suggested to limit outdoor exertion in this situation.
We know, one of the veritable manifestations of environment degradation is air pollution. Environmental degradation means degradation ‘through depletion of resources such as air, water and soil; the destruction of ecosystems; habitat destruction; the extinction of wildlife; and pollution. There are mainly three different types of environmental degradation. They are land degradation, water degradation, and air degradation. The degradation of these three environments impacts the global climate and living conditions to a great extent’
According to environment scientists, ‘the air quality is categorized as good when the AQI score remains below 50. The air is classified as moderate when the score is 51 to 100. But when the number is between 101 and 150, the air is classified as unhealthy for sensitive groups. The AQI, an index for reporting daily air quality, tells people how clean or polluted the air of a certain city is, and what associated health effects might be a concern for them. Bangladesh’s overcrowded capital has been grappling with air pollution for a long time. The quality usually improves during monsoon.’
Air pollution in Dhaka has gone a dizzying height ‘killing thousands prematurely each year.’ According to the Department of Environment (DoE), ‘the density of airborne particulate matter (PM) reaches 463 micrograms per cubic meter (mcm) in the city during December-March period – the highest level in the world. Mexico City and Mumbai follow Dhaka with 383 and 360mcm respectively. An estimated 15,000 premature deaths, as well as several million cases of pulmonary, respiratory and neurological illness are attributed to poor air quality in Dhaka, according to the Air Quality Management Project (AQMP), funded by the government and the World Bank.’
As per reports published recently, ‘vehicular air pollution is a major cause of respiratory distress in urban Bangladesh. If pregnant mothers come across excessive pollution, it may cause premature death of their children. According to the National Institute of Diseases of Chest and Hospital (NIDCH), nearly seven million people in Bangladesh suffer from asthma; more than half of them are children. Cases of children suffering from bronchitis and chronic cough have also shot up in recent years. Children breathe more air relative to their lung size than adults. They spend more time outdoors, often during midday and afternoons when pollution levels are generally highest. WHO air quality guidelines (2005) recommend a maximum acceptable PM level of 20mcm; cities with 70mcm are considered highly polluted. Airborne lead is the worst of the harmful PMs. By penetrating the lungs and entering the blood stream, lead may cause irreversible neurological damage as well as renal disease, cardiovascular effects, and reproductive toxicity. The phasing out of petrol-driven two-stroke auto-rickshaws in 2003 and their replacement with four-stroke versions, which use a much cleaner burning fuel (compressed natural gas), significantly decreased the volume of air contaminants. But, according to DoE sources, a sharp increase in the number of vehicles and construction sites in 2004-2008 led to a deterioration of Dhaka’s air quality. Old, poorly serviced vehicles, 1,000 brick kilns, dust from roads and construction sites, and toxic fumes from industrial sites are major sources of air pollution. So, the authorities should take the initiative to reduce air pollution in Dhaka city.’
Air pollution is caused by ‘solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes and wildfires. The solid and liquid particles suspended in our air are called aerosols.’
According to the website, ‘poisonous carbon monoxide, sulphur dioxide, nitrogen dioxide, suspended particulate matter (PM-10) and particulate matter (PM-2.5) exist in Dhaka’s air beyond permissible level for human body. Due to increase of PM-10 and PM-2.5, people lose lung function and suffer from chronic respiratory and cardiovascular diseases while nitrogen dioxide increase risks of bronchitis and pneumonia. Nitrogen dioxide causes respiratory infection. Carbon monoxide tends to reduce ‘delivery of oxygen into the human body, creates severe headache and decreases visual perception and manual dexterity’.
Faulty vehicles contribute to air pollution. ‘Only the diesel-run vehicles contribute about 60 per cent of such particles in the air’.
Air pollution is caused by the diesel-run vehicles, mainly buses and trucks, brick kilns ‘There are 4,000 brick kilns around the city, which use tyres, wood and low-quality coal, emitting poisonous particles into the air. But no initiative has been taken yet to measure quantity of poisonous particles emitting from brick kilns. The height of brick kiln chimneys has been increased to reduce air pollution but the initiative failed as the government failed to ensure quality of fuel used in the kilns.’
Carbon di-oxide (CO2) is a major absorber of infrared radiation emitted towards thespace from the earth surface. Thus, it has crucial role in planetary temperature structure. Carbon monoxide (CO), if inhaled, is absorbed from the lung alveoli 300 times faster than oxygen. High concentration of CO in blood makes it difficult for heart to pump blood through arteries. Unburnt hydrocarbon may form ozone with oxides of nitrogen which is a central nervous system depressant. Other hydrocarbons cause convulsion of CNS.
Oxides of nitrogen (NOx) cause dilatation of air spaces in lungs. NO2 causes damages to bronchioles and alveolar ducts. NO2 is also suspected to impair the defense mechanism of respiratory system. Infants and children are more susceptible.
Diesel emits suspended particulate matter (SPM) which contains shoot. Shoot is responsible for reduction of atmospheric visibility and absorb and carry organic compound to lungs.
Around 75% of the ingested lead is deposited in bones and tissues causing irreversible brain and kidney damage. Growing nervous system of young children is particularly vulnerable.”
One of the worst cases of air pollution is Dhaka, the capital city of Bangladesh. India’s Delhi is the worst. The Dhaka dwellers are experiencing many health effects of worst air. People, especially children, adults and women suffering from respiratory diseases are advised to avoid outdoor activities while everyone else is suggested to limit outdoor exertion in this situation.
We know, one of the veritable manifestations of environment degradation is air pollution. Environmental degradation means degradation ‘through depletion of resources such as air, water and soil; the destruction of ecosystems; habitat destruction; the extinction of wildlife; and pollution. There are mainly three different types of environmental degradation. They are land degradation, water degradation, and air degradation. The degradation of these three environments impacts the global climate and living conditions to a great extent’
According to environment scientists, ‘the air quality is categorized as good when the AQI score remains below 50. The air is classified as moderate when the score is 51 to 100. But when the number is between 101 and 150, the air is classified as unhealthy for sensitive groups. The AQI, an index for reporting daily air quality, tells people how clean or polluted the air of a certain city is, and what associated health effects might be a concern for them. Bangladesh’s overcrowded capital has been grappling with air pollution for a long time. The quality usually improves during monsoon.’
Air pollution in Dhaka has gone a dizzying height ‘killing thousands prematurely each year.’ According to the Department of Environment (DoE), ‘the density of airborne particulate matter (PM) reaches 463 micrograms per cubic meter (mcm) in the city during December-March period – the highest level in the world. Mexico City and Mumbai follow Dhaka with 383 and 360mcm respectively. An estimated 15,000 premature deaths, as well as several million cases of pulmonary, respiratory and neurological illness are attributed to poor air quality in Dhaka, according to the Air Quality Management Project (AQMP), funded by the government and the World Bank.’
As per reports published recently, ‘vehicular air pollution is a major cause of respiratory distress in urban Bangladesh. If pregnant mothers come across excessive pollution, it may cause premature death of their children. According to the National Institute of Diseases of Chest and Hospital (NIDCH), nearly seven million people in Bangladesh suffer from asthma; more than half of them are children. Cases of children suffering from bronchitis and chronic cough have also shot up in recent years. Children breathe more air relative to their lung size than adults. They spend more time outdoors, often during midday and afternoons when pollution levels are generally highest. WHO air quality guidelines (2005) recommend a maximum acceptable PM level of 20mcm; cities with 70mcm are considered highly polluted. Airborne lead is the worst of the harmful PMs. By penetrating the lungs and entering the blood stream, lead may cause irreversible neurological damage as well as renal disease, cardiovascular effects, and reproductive toxicity. The phasing out of petrol-driven two-stroke auto-rickshaws in 2003 and their replacement with four-stroke versions, which use a much cleaner burning fuel (compressed natural gas), significantly decreased the volume of air contaminants. But, according to DoE sources, a sharp increase in the number of vehicles and construction sites in 2004-2008 led to a deterioration of Dhaka’s air quality. Old, poorly serviced vehicles, 1,000 brick kilns, dust from roads and construction sites, and toxic fumes from industrial sites are major sources of air pollution. So, the authorities should take the initiative to reduce air pollution in Dhaka city.’
Air pollution is caused by ‘solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes and wildfires. The solid and liquid particles suspended in our air are called aerosols.’
According to the website, ‘poisonous carbon monoxide, sulphur dioxide, nitrogen dioxide, suspended particulate matter (PM-10) and particulate matter (PM-2.5) exist in Dhaka’s air beyond permissible level for human body. Due to increase of PM-10 and PM-2.5, people lose lung function and suffer from chronic respiratory and cardiovascular diseases while nitrogen dioxide increase risks of bronchitis and pneumonia. Nitrogen dioxide causes respiratory infection. Carbon monoxide tends to reduce ‘delivery of oxygen into the human body, creates severe headache and decreases visual perception and manual dexterity’.
Faulty vehicles contribute to air pollution. ‘Only the diesel-run vehicles contribute about 60 per cent of such particles in the air’.
Air pollution is caused by the diesel-run vehicles, mainly buses and trucks, brick kilns ‘There are 4,000 brick kilns around the city, which use tyres, wood and low-quality coal, emitting poisonous particles into the air. But no initiative has been taken yet to measure quantity of poisonous particles emitting from brick kilns. The height of brick kiln chimneys has been increased to reduce air pollution but the initiative failed as the government failed to ensure quality of fuel used in the kilns.’
Carbon di-oxide (CO2) is a major absorber of infrared radiation emitted towards thespace from the earth surface. Thus, it has crucial role in planetary temperature structure. Carbon monoxide (CO), if inhaled, is absorbed from the lung alveoli 300 times faster than oxygen. High concentration of CO in blood makes it difficult for heart to pump blood through arteries. Unburnt hydrocarbon may form ozone with oxides of nitrogen which is a central nervous system depressant. Other hydrocarbons cause convulsion of CNS.
Oxides of nitrogen (NOx) cause dilatation of air spaces in lungs. NO2 causes damages to bronchioles and alveolar ducts. NO2 is also suspected to impair the defense mechanism of respiratory system. Infants and children are more susceptible.
Diesel emits suspended particulate matter (SPM) which contains shoot. Shoot is responsible for reduction of atmospheric visibility and absorb and carry organic compound to lungs.
Around 75% of the ingested lead is deposited in bones and tissues causing irreversible brain and kidney damage. Growing nervous system of young children is particularly vulnerable.”
(Dr. Mozumder is Pro-VC, BUP and Dr. Mashreque is a retired professor, Chittagong University).
