Air Pollution

Prof. Dr. Ahmad Kamruzzaman Majumder :
People of Dhaka city have been fortunate enough to enjoy the good air in the last ten days of July, 2021 due to mainly three reasons, 1st one was lockdown, 2nd one was the Eid holiday and 3rd one was monsoon rain. This week had been a magical week considering the air quality history of Dhaka city. Dhaka has been at the forefront of polluted air for several years now. According to the latest report released by IQAir, an international organization based in the United States, Bangladesh is at the top position in terms of air pollution in 2019 and 2020. This report also mentions that Dhaka got the second position in terms of air pollution among the capital cities of the world. The report further states that in 2020, the average amount of (Particulate Metter) PM2.5 in the air of Bangladesh was 77.1 micrograms per cubic meter (µg/m3) per year which is 5.5 times higher than the National Ambient Air Quality Standard (NAAQS) level. But in ongoing COVID-19 lockdown period gradually the capital city of Bangladesh has started coming out of that place. At present, Dhaka is ranked 77th on the list of polluted cities in the world. This image was seen on July 30th in the IQAir. In July, the average air quality in Dhaka was only 31.31 micrograms per cubic meter. As such, the people of the capital got fresh air in the recently departed July.
Another very recent study has conducted by Center for Atmospheric Pollution Studies (CAPS), Department of Environmental Science, Stamford University Bangladesh under USAID and FCDO funded Anti-Pollution Advocacy Project where daily air and noise data were collected from 10 important places in Dhaka city. After analysed the data we found that in the month of July the average PM2.5 was found to be 53.46 micrograms per cubic meter in the Gulshan-2 area and the average minimum PM2.5 was 16.89 micrograms per cubic meter in the Motijheel area which is within the permissible limit. Again, in 2021, the day of Eid-ul-Azha (July 21) in Dhaka city with a continuous 11 hours (7 am to 5 pm) for a total of 13 hours, the AQI was below 50 (good) whereas, in 2020, Eid-ul-Azha only 4 hours the AQI was good. As of 24 hours in 2021, the AQI on 21st July was 96, which was 56 on 22nd July, 44 on 23rd July and 29 on 24th July. In particular time of the day AQI came down as law as 4 and PM2.5 came to 2 micrograms per cubic meter.
According to a survey by the Center for Atmospheric Pollution (CAPS), uncontrolled road digging, unfit vehicles and large megaprojects are main the sources of air pollution in Dhaka city. Precipitation is one of the factors that can reduce the amount of particulate matter in the air. This year, before the Eid-ul-Azha, on the day of Eid and after, it rains in Dhaka, which reduces the amount of PM2.5 in Dhaka city. Therefore, the amount of air pollution during Eid has been observed to be low due to the closure of public transport, reduced human movement and high rainfall during the monsoon season. On the other hand, the number of people heading to Dhaka due to the lockdown in the prevention of coronavirus infection is relatively low. Due to this the lack of movement of vehicles can be noticed, as a result, air pollution in Dhaka is decreasing. The total population of the Dhaka Metropolitan area is 2 crore 17 lakhs. About 1 crore and more people have left Dhaka this Eid but only 30 lakhs have returned so per. In other words, because of various activities of the total population in Dhaka city, such as the traffic was less. Factories, construction work or development work were closed at that time. As a result, air pollution is relatively low. Although the major projects were running at a slower pace than usual during this time of lockdown, the number of people and vehicles moving through the project area was less and the spread of pollutants from the source was less, resulting in improved air quality. The third major source of air pollution is unfit vehicles and severe traffic jams. Looking at the current picture of Dhaka, it is understood that the number of vehicles on the road is less and the amount of pollution is much less. There is also the effect of clean air on human visibility. According to the Meteorological Department, where people seen normally 2 to 4 km away things in Dhaka now 8 to 9 km away things are seen at this time. Although the study conducted on only Dhaka city by the Center for Atmospheric Pollution Studies (CAPS), but it can be assumed that the air quality in other parts of the country has also improved.
The current improvement in Dhaka’s air quality in the COVID-19 situation is only temporary, in no way sustainable or permanent solution. This is just a positive manifestation of a particular disaster situation. But it also shows us what the main sources of air pollution are and how to control air pollution. Also shows us what are the benefits of preventing air pollution.
Therefore, with the improvement of the Corona situation, we must adopt the plan and determination to build a habitable Dhaka city in the future by using this experience as a means of identifying the sources and not forgetting the present condition of the air pollution free Dhaka city. And for this the following issues can be seriously considered:
Strict control of expired and unfit vehicles, install high-tech brick kilns, construction materials should be covered during transportation, repair work should be completed through coordination, advanced technology incinerators should be used in waste management and energy can be generated from waste and further research on inland air pollution, In Public Service Commission (BCS) needs to include environmental cadres, The Clean Air Act 2019 needs to be implemented as soon as possible and development activities need to be coordinated through the introduction of city governance.

(Dr. Majumder is Dean, Faculty of Science, Chairman, Department of Environmental Science, Stamford University Bangladesh).