Professor Dr. Ahmad Kamruzzaman Majumder :
The Economist’s Intelligence Unit (EIU) publishes a list of uninhabitable cities every year and sadly in 2019 Dhaka was identified as the third least livable city in the world. And air pollution is one of the regulators for bringing Dhaka down to an uninhabitable city. The Bangladesh Poribesh Andolon (BAPA) has expressed fears that high levels of air pollution in Bangladesh could increase the number of deaths of the coronavirus. It is also feared that as the temperature drops in the coming winter season, which could lead to more air pollution, coronavirus may increase which might be a triggering factor for the second wave of Covid-19 in Bangladesh.
Fine particles are more dangerous than coarse particles. Among all sizes of particulate matter microscopic or ultrafine particulate matter is dominated in Dhaka due to its origin mostly from burning. In 2019 a study conducted by the Center for Atmospheric Pollution Studies (CAPS) at Stamford University Bangladesh found that the amount of tiny particulate matter (PM2.5) in the air in Dhaka city is about 80 percent of the total particulate matter, which is one of the most alarming causes of lung disease. These tiny particles cause lung cancer, asthma, bronchitis, tuberculosis, kidney disease, high blood pressure, congenital disabilities, diabetics, heart attack, liver problems, effects on pregnant mothers, eye irritation, skin diseases, and impact on mental health.
Analyzing the data collected through the advanced atmospheric research center at the US Embassy’s own premises in Baridhara, Dhaka, it is seen that the first 24 days of March 2020 (104 µg/m3) in Dhaka the averages air quality was 15 percent and 20 percent better compare to for year 2018 (116µg/m3) and 2019 (123µg/m3) respectively. The upward trend (average 106µg/m3) of air pollution was noticed in the next four days after the closure of educational institutions on 16th March 2020 as the movability of the scary people has increased as many people start to move to village.
Similarly, after the announcement of general holiday on 25th March, the people were busy to leaving the capital on 25th to 27th March, which increases PM2.5 for about 19 percent (124µg/m3) higher than the average (104µg/m3) of before the general holiday (1 to 24 March 2020). Despite the limited movement of people during this time, it took a long time for the particles floating in the air, the long-standing dust on the leaves of trees and the dust in other installations to subside. Dhaka’s air quality started getting better from 28th March and a minimum of 49µg/m3 was recorded on 30th March. Except for the first three days, the 44 days general holiday from 28th March to 10th May, the average PM2.5 level in the air at this time (only 54µg/m3, but the average from March 25th was only 59µg/m3) before the announcement of the general holiday. The day i.e. 1 to 24 March 2020 was about 52 percent lower than the average level (104µg/m3).
However, in this case, it is not possible to say for sure that the general holiday and lockdown is the only reason for this improvement in Dhaka’s air quality. Here the special effects of meteorological parameters such as temperature, rainfall and humidity can be noticed. For example, last Wednesday, May 6, 2020, at 4 am, the amount of PM2.5 in the air of Dhaka was 80µg/m3 and the AQI value was 176. The air quality improved considerably after the morning rain. After 11 a.m., the amount of PM2.5 in the air dropped to 7.7µg/m3 and the Air Quality Index (AQI) value dropped to 32. On February 25, 2017, Dhaka’s AQI was as low as 13.
It is noteworthy that during the last 47 days of public holidays due to Covid-19 coronavirus (March 25 to May 10, 2020) the average level of PM2.5 (59µg/m3 in 2016, 59µg/m3 in 2017, 64 µg/m3 in 2018, 89 µg/m3 in 2019, 59 µg/m3 in 2020) was 7 percent and 34 percent lower than the average values for the same period in 2018 and 2019, respectively. Surprisingly, the average level of PM2.5 for the same period in 2016 and 2017 was almost the same in 2020 during COVID-19 period. According to the Bangladesh Environmental Conservation Rules, 2007, the daily average allowable limit of PM2.5 in the air is 65µg/m3.
A review of 47 days (March 25 to May 10, 2020) of Dhaka’s Air Quality Index during the Corona period of 2020 and the previous four years (2016 to 2019) shows that during this period of 2020, Dhaka’s air quality improved of earlier years. Nevertheless it is bit complicated to assess the impact of the covid-19 on air pollution because rain also has a strong role to play in controlling the air quality. The Department of Environment has not yet determined how the air quality was during lockdown or whether they has been measured or not, as no information was available on the department’s website since March 22, 2020.
The current improvement in Dhaka’s air quality in the COVID-19 situation is only temporary, in no way sustainable or permanent. This is just a positive manifestation of the particular disaster situation. But it also shows us again what the primary sources of air pollution are. It taught us how to control air pollution ad what are the benefits of preventing air pollution. Therefore, as Corona’s situation improves, we must not forget the current state of air pollution-free Dhaka city, but use this experience to identify sources and adopt a plan and determination to build a livable and sustainable Dhaka city in the future.
(Professor Dr. Ahmad Kamruzzaman Majumder, Dean, Faculty of Science, Chairman, Department of Environmental Science, Stamford University Bangladesh, Founder and Director, Center for Atmospheric Pollution Studies (CAPS) & Joint Secretary, Bangladesh Poribesh Andolon (BAPA), E-mail: [email protected])
