Air quality crisis: Dhaka struggles with dangerous pollution levels

Dhaka's air improved during COVID-19 due to less pollution but is now back to earlier levels

Despite extensive debates on Dhaka’s air quality, the harsh reality remains—breathing clean air in the capital has become a luxury.

Prof Ahmad Kamruzzaman Majumdar from Stamford University’s environmental science department analysed eight years of Dhaka's air pollution data. His findings revealed that out of 2702 days, only 57 days had clean air. The remaining days featured air classified as unhealthy and hazardous.

“About 65 to 70 percent of the yearly air pollution occurs from November to March,” he said.

The alarming situation is evident in increased respiratory illnesses during dry seasons.

Pulmonologist Kazi Saifuddin Ben Noor highlighted that respiratory diseases rise by nearly 1.5 times during winter.

“Based on my 25 years of experience, winter is a risky and hazardous period for respiratory patients. Allergies worsen, and chronic asthma becomes uncontrollable,” he told bdnews24.com, recommending mask usage for all.

Public health expert Mustuq Ahmed stressed the urgency of combating Dhaka’s air pollution, calling for immediate action over cost considerations.

“The economic loss is secondary. The real issue is health—those affected can neither work nor recover easily,” he said.

DUST AND SMOKE DOMINATE THE CITY

On Thursday, Mahbub Mia was seen holding his T-shirt over his nose to cross the dust-filled Dhaka-Ashulia Highway.

“The dust suffocates me. My ears itch. If not for work, I’d never come here,” he said.

The same day, along Abdullahpur’s Dhaka-Ashulia Elevated Expressway construction site, vehicles stirred up dust clouds.

Materials lay uncovered, and no water was sprayed for dust control between 10am and 2pm, violating the 2022 air pollution control regulations.

The regulations mandate covering construction materials, spraying water at least twice daily, and transporting construction supplies in covered vehicles.

Dust clouds were reported from Mohakhali to Tongi, Mirpur to Old Dhaka, with vehicles kicking up dust across the city.

Nazifa Anjum, an Agargaon resident, said: “Even minor dust here bothers me greatly. For asthma patients like me, it’s unbearable. Masks don’t help; I still catch colds and feel suffocated.”

Regular commuter Arif Hossain, who travels through the Aricha Highway, faces a similar ordeal.

“The stretch from Hemayetpur to Gabtoli is a nightmare with dust. Even with a mask, I cough and sneeze. It causes rashes and breathing issues,” he said.

In areas like Tejgaon’s Nakhalpara, construction for railway expansion has been ongoing for two months. Dust rises with every passing rickshaw, bike, or pedestrian.

Even Afatabnagar, despite no visible construction, suffers from dust stirred by vehicles. Many buses in the area emit thick black smoke.

At night, Mirpur’s roads are plagued by uncovered sand trucks, worsening the already dire situation.

SOURCES OF AIR POLLUTION IN BANGLADESH

Citing a 2021-22 World Bank study, Md Ziaul Haque, director of the Air Quality Management Wing at the Department of Environment, told bdnews24.com that intercontinental air pollution accounts for 30 percent, firewood use 28 percent, power plants 24 percent, brick kilns 13-15 percent, construction activities 11 percent, waste burning 11 percent, and vehicles 5 percent of the air pollution in Bangladesh.

However, he noted discrepancies in the data, saying: "I believe vehicle emissions are higher. Moreover, during winter, construction activities increase, brick kilns operate, factories remain active, waste is burned, and building materials like sand are left exposed on roads, which worsens air quality as vehicles stir up dust."

According to him, air pollution levels have increased annually by 1-2 percent until 2023.

He said, "Daily air quality index, or AQI, at 150 may be tolerable for Dhaka, but it is far from ideal. The target should be 50. Even reducing it below 150 would mark some progress."

AIR QUALITY INDEX (AQI) AND ITS PARAMETERS

Air quality is determined by the concentration of fine particulate matter, PM10 and PM2.5, per cubic metre, measured in micrograms.

Other factors include sulphur dioxide, carbon monoxide, nitrogen dioxide, and ground-level ozone. The AQI levels are classified as follows:

51-100: Moderate/acceptable

101-150: Unhealthy for sensitive groups

151-200: Unhealthy

201-300: Very unhealthy

301+: Hazardous

Key Sources of Pollution in Dhaka

Khairul Baker, supervising engineer of Dhaka South City Corporation's Environment, Climate, and Disaster Management Cycle, highlighted transport, construction work, and improper use of construction materials as major contributors to Dhaka's pollution.

He added that brick kilns and factories also play a significant role, noting a lack of research on specific pollution sources.

Prof Kamruzzaman Mazumder, founder of the Centre for Atmospheric Pollution Studies, or CAPS, attributed 51 percent of air pollution to construction, 29 percent to industrial activities and brick kilns, 16 percent to vehicles, and a smaller share to waste burning and household sources. He mentioned a 5-7 percent reduction in pollution in October 2023 compared to the previous year, citing reduced construction activities.

IMPACT OF WINTER ON POLLUTION

Prof Kamruzzaman warned that pollution worsens during winter and is exacerbated by transboundary air pollution from neighbouring countries.

He emphasised adhering to construction regulations and halting waste burning as critical measures.

EXPERT OPINIONS AND RECOMMENDATIONS

Md Hadiuzzaman, a professor at the civil engineering department of Bangladesh University of Engineering and Technology, or BUET, identified unregulated construction, unfit vehicles, and brick kilns as primary sources.

He criticised Dhaka’s poorly maintained vehicles and ongoing road excavation, which perpetuate dust and emissions.

To address this, he recommended:

Monitoring construction activities and applying water regularly at sites

Ending the "road digging culture"

Removing unfit vehicles from roads

LESSONS FROM THE COVID-19 PANDEMIC

Asib Ahmed, an assistant professor at Dhaka University’s geography and environment science department, observed improved air quality in Dhaka during the COVID-19 lockdown due to reduced activities.

However, post-pandemic, pollution levels returned to pre-lockdown levels, with vehicles being a significant contributor.

He added, "The necessary steps to address pollution are not being taken, which is the main problem."

WHY DOES AIR QUALITY WORSEN AT NIGHT?

From Nov 13, IQAir's rankings show Dhaka's air quality index typically remains between 150-200 during the day, but spikes to 200-300 after 10pm.

The Department of Environment's data also highlights that Dhaka's AQI stayed above 150 on most days since Oct 12, dipping below 150 on only 12 occasions over 40 days.

On Nov 16, the AQI hit a peak of 242.

DSCC’s Khairul cited late-night activities such as sand-laden trucks and construction material transportation as major contributors to the rise in pollution levels.

"Many factories operate at night, emitting heavily polluted air, adding to the spike," he explained.

STEPS TO CONTROL POLLUTION

Efforts to combat air pollution remain fragmented.

The Ministry of Environment, Forest and Climate Change did not respond to queries about specific measures.

Mohammad Ziaul Haque, director of the air quality management wing at the Department of Environment, said letters are sent to relevant authorities like city corporations and the local government ministry to fulfil their responsibilities.

However, monitoring challenges persist due to a lack of manpower.

Dhaka South City Corporation plans to begin spraying water on major roads this month, but Khairul pointed to challenges, including a water shortage and pollution in nearby rivers.

“We’re surrounded by problems. Our magistrates and regional executive officers raise awareness and impose fines on those who leave construction materials uncovered,” he said.

Dhaka North City Corporation has already started watering major roads in the mornings and evenings.

“Our regional executive officers regularly inspect areas. If they find exposed materials causing dust, fines are imposed. We often take such measures,” DNCC spokesperson Mokbul Hossain said.

[Writing in English by Arshi Fatiha Quazi]