Air pollution in Dhaka
Air pollution in capital city Dhaka has gone higher than Mexico City and Mumbai 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.
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.