Overall air quality status in Dhaka previously showed that winter was the most polluted season. But according to a study, things are changing in recent years.
Air pollution in the city reaches “unhealthy” level even before the winter sets in, exposing its residents to health risks.
Dhaka’s air remained unsuitable for breathing for more than half of last year. The air quality remained “very unhealthy” and “extremely unhealthy” for 197 days, according to an analysis of Air Quality Index data, monitored by the Department of Environment under its Clean Air and Sustainable Environment (CASE) project.
The duration of the “unhealthy” air level is increasing day by day, it said.
According to the approved Air Quality Index (AQI) in Bangladesh, an AQI range between 151-200 is categorised as “unhealthy”, while the range between 301-500 is classified as “extremely unhealthy”.
A study by environment researcher Atik Ahsan found that the capital’s air quality category ranged between “unhealthy” and “extremely unhealthy” for 165 days in 2014. The duration increased to 173 days in 2015, 185 days in 2017 and 197 days in 2018.
“Roads in Dhaka remain unclean almost round the year. Repair and maintenance of the roads by different government agencies worsen the situation as there is no proper management of the sites. It is alarming that Dhaka’s air quality never improves for a day in January and February,” said Atik, a medical anthropologist and a former senior research investigator of the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b).
Experts blamed increasing number of construction works, rise in the number of vehicles and worsening traffic congestion for the decreasing air quality of Dhaka. The operation of brick kilns around the capital in the winter in full swing aggravates the situation.
Talking to The Daily Star, Prof Abdus Salam of Dhaka University said, “Previously, there were some air pollution hotspots in Dhaka. But in the recent years, such areas have widened to almost the entire city as roads see traffic jams throughout every working day. The situation becomes worse due to some ongoing mega projects.”
According to breathelife2030.org, the air in Dhaka was 5.7 times above the safe pollution level, set out by the World Health Organization, yesterday. The breathelife2030.org is a platform which combines public health and climate change expertise on implementing solutions to air pollution.
A recent study published in the journal Nature Sustainability said expectant mothers face an increased risk of “silent” miscarriage due to air pollution.
The pollution is already known to raise the risk of premature birth, low birth weight and life-threatening health complications for pregnant women, like preeclampsia, which is marked by high blood pressure, or gestational hypertension.
THREAT TO PUBLIC HEALTH
Studies show that Dhaka’s air is contaminated not only with heavy metals like lead, chromium, cadmium, nickel, arsenic, manganese and copper, but also with other poisonous particles.
The presence of pollutant particles in the air even on a normal day, except for those in the rainy season, is more than three to four times higher than the desirable limit.
The level of air pollution in Dhaka is so alarming that it is often ranked among the top 10 most polluted cities in the global Air Quality Index.
Indoor and outdoor air pollution led to 1.23 lakh deaths in Bangladesh in 2017, according to the State of Global Air 2019 report published recently by US-based organisation Health Effects Institute and Institute for Health Metrics and Evaluation.
It said air pollution was the fifth highest mortality risk factor globally.
Ziaul Haque, director of Air Quality at the DoE, said it would be tough to control the city’s air pollution if the construction works and movement of vehicles were not kept within a limit.
He said they would launch a drive against the polluters soon.