Dr Biswas, presenting the keynote paper at a media workshop on Air Quality Index for Dhaka, last Thursday, said that Dhaka's air quality has improved by between 27 to 40 per cent, in the past year owing to various corrective measures taken by the present government. But the transport sector still remains the major pollutant, added Biswas.

The Department of Environment (DOE), who jointly organised the workshop with the Forum of Environmental Journalists of Bangladesh (FEJB), is planning to launch an Air Quality Index (AQI) for Dhaka within a few months. Like cities in developed countries, this will inform the public of the rate of air pollution and create awareness among them to reduce hazardous emissions.

"Initially, DOE will release the AQI three days a week because of our limited infrastructure. Later we will be able to present each day's AQI by upgrading our facility and equipment," said director general of the DOE, Dr Omar Faruque Khan.

"The Air Quality Management Project, financed by the World Bank and the Government of Bangladesh, has been continuously monitoring the air of Dhaka city from the Continuous Air Monitoring Station (CAMS) located at Sangsad Bhaban, over the past one year. The AQI will be provided on the basis of the data obtained from that station," said Faruque Khan.

At present, the USA, Australia, Canada, the UK, Hong Kong, Malaysia and a few other countries prepare their AQI and regularly inform people through the media. "We will send three days AQI to the meteorological department of Bangladesh and it will be available with the regular weather forecast in the print as well as electronic media," said Faruque Khan.

"The particulate matter (PM) contained in the smoke emitted from vehicles during the winter days is now the major cause of air pollution. Among the particulates, PM 2.5which a person can easily inhale due to its small diameteris the major concern for Dhaka's air," said Dr Biswas.

"City dwellers enjoy pollution free days during the rainy season. The level of pollution comes down drastically, well below the mark prescribed by the United States Environment Protection Agency (USEPA)," said Biswas.

The keynote speaker added, "Air pollution in Dhaka can be attributed to rapid urbanisation, increased economic activity, high population density and traffic congestion."

"I urge DOE to prepare the AQI in a way that the media can understand it precisely and present it for the public through news and electronic media without any difficulties," suggested FEJB chairman, Quamrul Islam Chowdhury.

Project director of the Air Quality Management Project, Abdul Kader, technical director of the DOE, Md Riajuddin, journalists and others also took part in the discussion.