Dhaka Grapples with Severe Air Pollution, Ranking Among World’s Worst
Dhaka, the bustling and densely populated capital of Bangladesh, found itself once again at the forefront of a global environmental crisis, ranking as the second most polluted city worldwide on Monday morning. At 9:17 am, the city registered a concerning Air Quality Index (AQI) of 254, placing its air quality in the ‘very unhealthy’ category. This designation signals a significant and immediate threat to public health, urging residents to take precautions.
The grim AQI report positioned Dhaka behind Lahore, Pakistan, which held the top spot with an AQI of 282. Following closely were Delhi, India, at third with an AQI of 225, and Ulaanbaatar, Mongolia, in fourth place with an AQI of 200. These figures highlight a widespread regional issue with air quality, impacting millions of lives across South Asia and beyond.
Understanding the AQI scale is crucial for appreciating the severity of the situation:
- 0-50: Good – Air quality is considered satisfactory, and air pollution poses little or no risk.
- 51-100: Moderate – Air quality is generally acceptable. However, there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
- 101-150: Unhealthy for Sensitive Groups – Members of sensitive groups may experience health effects. The general public is less likely to be affected.
- 151-200: Unhealthy – Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.
- 201-300: Very Unhealthy – Health alert: everyone may experience more serious health effects.
- 301+: Hazardous – Health warnings of emergency conditions. The entire population is more likely to be affected.
The AQI serves as a vital daily indicator, providing residents with clear information about the prevailing air quality and its potential health implications. In Bangladesh, the calculation of the AQI is a comprehensive process, taking into account five primary pollutants:
- Particulate Matter (PM10 and PM2.5): Tiny particles suspended in the air, with PM2.5 being particularly dangerous as it can penetrate deep into the lungs.
- Nitrogen Dioxide (NO2): A gas primarily produced by the burning of fossil fuels.
- Carbon Monoxide (CO): A colorless, odorless gas that can reduce the oxygen-carrying capacity of the blood.
- Sulfur Dioxide (SO2): A gas often associated with the burning of fossil fuels containing sulfur.
- Ozone (O3): Ground-level ozone, a major component of smog, is formed when pollutants react in sunlight.
Dhaka’s struggle with air pollution is not a new phenomenon. The city consistently experiences a marked deterioration in air quality during the winter months, a period characterized by lower temperatures, less wind, and increased emissions from various sources. Conversely, air quality typically sees improvement with the arrival of the monsoon season, when rainfall helps to wash pollutants from the atmosphere.
The health consequences of such persistent air pollution are dire. The World Health Organization (WHO) estimates that ambient air pollution is responsible for approximately seven million premature deaths globally each year. These deaths are primarily attributed to a range of serious health conditions, including:
- Stroke
- Heart disease
- Chronic obstructive pulmonary disease (COPD)
- Lung cancer
- Acute respiratory infections
The recurring high AQI readings in Dhaka underscore the urgent need for sustained and effective interventions to mitigate pollution sources, improve urban planning, and protect the health of its citizens and the wider population.
