A recent World Air Quality Report says Bangladesh has the most polluted air in the world and Dhaka is the second most polluted capital city.
At a country level, the new report says weighted by population, Bangladesh emerges as the most polluted country in the world. Gurgaon, a suburb of the Indian capital New Delhi, is the world's most polluted city.
According to the report, air pollution will cause around seven million premature deaths globally next year and have a major economic impact.
Bangladesh, one of the most densely-populated countries in the world, has been struggling with air pollution for long. Dhaka, the country's capital, often finds its place among the most polluted cities in global indices.
Brick kilns and vehicles run on fuel with higher level of sulfur have been identified as the major sources of air pollution in the country.
. 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.
There is no denying that air pollution has reached menacing proportions in the city which has become virtually unliveable. Urban air in the city is thick with fumes; water either in the rivers, ponds or tube-wells, is polluted, and the land is poisoned. Unchecked dumping of waste, a lot of it toxic, noxious emissions from vehicles and the pesticides used in farmlands are the main causes.
Although the city did fare well in terms of reducing pollution, the situation is still alarming, posing serious health hazards for city dwellers. Things get worse in dry season as air, thick with particulates, becomes a prevalent cause of chest and respiratory diseases.
According to the Department of Environment (DoE), the density of airborne particulate matter (PM) has reached 247 micrograms per cubic metre (mcm) in Dhaka which is nearly five times the acceptable level of 50 PM per mcm set by the National Ambient Air Quality Standard (NAAQS) of Bangladesh.
Airborne particulates are considered more harmful when they are 10 micrometres or smaller in diameter and in Dhaka the density of PM which is 2.5 micrometers or smaller has been found to be 9.0 times higher than the NAAQS recommendation. Ambient air in the city becomes extremely polluted between October and March every year when rain is scarce and when thousands of brick kilns become operational, burning used automobile and rickshaw tyres, low grade coal and in many cases fuel-wood.
World Health Organisation (WHO) air quality guidelines however recommend a maximum acceptable PM level of 20mcm compared to Bangladesh standard of 50. Cities with 70mcm are considered highly polluted. Airborne lead is the worst of the harmful PMs.
Although there is no definite study, doctors suggest exposure to such a volume of air pollution may cause premature deaths and also various diseases including pulmonary, respiratory and neurological illnesses. Air pollution has also an adverse effect on all other life forms including plants.
Cost of maintaining building structures in the urban areas also rises significantly due to such air pollution. The number of patients with different chest and respiratory diseases in the hospitals and clinics is on the rise.
If this trend of air pollution continues, those living in Dhaka city, will become exposed to ailments stated above and also other complications. The mental faculty of children will be adversely affected by lead pollution, which can also affect the central nervous system and cause renal damage and hypertension.
In addition to brick kilns, old buses, fleets of trucks and thousands of other poorly serviced vehicles contribute highly to the pollution. Moreover, dust from roads and construction sites and toxic fumes from industrial sites turn the air quality scenario even worse.
Industrial wastes are responsible for 60 per cent of the surface water pollution in and around Dhaka city while domestic wastes contribute to rest of the pollution. At present, underground water is extracted exploring 300 metres deep.
More than 0.35 million motor vehicles ply the roads in Dhaka. Diesel-run vehicles account for more than 80 per cent of the air pollution as most of them fail to comply with the emission standard. According to WHO guidelines, blood lead level above 10 microgram per deciliter is considered as lead poisoning.
A recent survey found lead concentration in urban children to be 5.8 to 21.6 microgram per decilitre and urban slum children's lead level ranged from 9.6 to 38.9 microgram per decilitre, three times more than the acceptable level.
Sadly enough, laws exist to book a polluter, but law enforcers shy away from using the laws in most cases because of an unholy alliance with the vehicle drivers. In most cases, polluting vehicles drive away emitting noxious fumes in the presence of the law enforcement personnel without being held up or booked. Old and dilapidated vehicles disappear from the roads during special drives by the law enforcers only to return after the drive comes to an end.
In the past, attempts to prohibit plying of old vehicles in Dhaka city streets failed either for political reasons or in the face of resistance by transport owners and their employees. But if the neighbouring countries can improve air quality of their cities by banning use of old vehicles and also relocating some of their polluting industries, authorities in Bangladesh can also do the same.
It is thus time to phase out old and black smoke emitting vehicles from city roads as our right to live in healthy environment largely depends on it. Good governance helped curb air pollution in cities like Bangkok, Kolkata, Kathmandu and Lahore while weak administration caused the increase of air pollution in Dhaka and Karachi.
Indeed, Bangladesh is one of the few countries that faces extreme hazards due to environmental degradation and resource depletion. The degradation of the environment has been highlighted in various forums because of its universal potential for chaos and disorder. Environmental problems faced by Bangladesh are far too many though largely caused by factors, which are teleological because of its geographical position.
The ecological hazards of pollution and resource depletion pose a potentially catastrophic threat to Bangladesh. The problem should be high on the agenda of the government as well as political parties. One hopes that the issue will get the priority it deserves.
The government should, in the circumstances, take the environmental threats seriously, and create public awareness and undertake action-oriented programmes.