Dhaka saw a marked improvement in the air quality on Wednesday (July 6). The air quality of the capital city has been classified - ‘moderate’ due to the monsoon showers in the country.
With an air quality index (AQI) score of 76 at 9.30am on Wednesday, the city ranked 19th in the list of cities with the worst air quality. Dhaka’s AQI was categorised as ‘acceptable’.
Pakistan’s Lahore, India’s Delhi and Peru’s Lima occupied the first three spots in the list with AQI scores of 185, 160 and 157 respectively.
When the AQI remains between 51 and 100, the air quality is acceptable, but there may be a risk for some people who may be unusually sensitive to particle pollution.
On the other hand, having a score below 50 on the AQI index means the air quality is satisfactory and air pollution poses little or no risk.
An AQI between 101 and 200 is considered ‘unhealthy’, particularly for sensitive groups. Similarly, an AQI between 201 and 300 is said to be ‘poor’, while a reading of 301 to 400 is considered ‘hazardous’, posing serious health risk to people.
AQI, an index for the measurement of everyday air quality, is used by government agencies to inform people how clean or polluted the air of a certain city is, and what associated health effects might be a concern for them.
In Bangladesh, the AQI is based on five criteria pollutants. These are- Particulate Matter (PM10 and PM2.5), NO2, CO, SO2 and Ozone.
Dhaka city has been struggling with polluted air for a long time. Alongside Dhaka, some other cities and towns in Bangladesh have also been grappling with air pollution issues. Its air quality usually turns unhealthy in winter and improves during the monsoon.
A report by the Department of Environment (DoE) and the World Bank in 2019 pointed out that the three main sources of air pollution in Dhaka. These are brick kilns, fumes from vehicles and dust from construction sites.
With the advent of winter, the city’s air quality starts deteriorating sharply due to the massive discharge of pollutant particles from construction work, rundown roads, brick kilns and other sources.
Air pollution consistently ranks among the top risk factors for death and disability worldwide. Breathing polluted air has long been recognised as increasing a person’s chances of developing a heart disease, chronic respiratory diseases, lung infections and cancer, according to several studies.
According to the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year, largely as a result of increased mortality from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections.
