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Air pollution in Dhaka adds a new worry to pandemic

November 23, 2020 00:00:00

Raihan, a resident of Dhaka's Shantinagar, had recovered from the COVID-19 illness about two months ago. He still has a cough as his lungs are yet to regain their full capacity. Doctors advised him to be on guard against the cold in winter and stay away from dust, reports bdnews24.com.

Raihan and many others, who have recovered from COVID-19, or have underlying respiratory complications will have to be extra-cautious in winter as experts worry that air pollution in Dhaka will be a major setback to combating the novel coronavirus in cold and dry weather. Unhygienic conditions in the city are likely to complicate respiratory issues further.

The experts say breathing unhealthy air damages the lungs and contracting COVID-19 under such conditions could raise the odds of dying from coronavirus infections. Proper coronavirus testing during winter is crucial for treatment, as COVID-19 symptoms are similar to those caused by cold weather.

A suspension of the public transport system and a lockdown that slowed construction work lowered dust levels in the city's air for months. The lifting of the curbs, however, led to a gradual rise of the harmful elements in the air again. With the advent of winter, air pollution coupled with low humidity has now reached the worrying levels.

The air quality of Dhaka and the rest of the country has been declining over the last two weeks, reaching hazardous degrees in some regions.

The quality of air depends on the amount of small floating dust particles (particulate matter or PM 10) and fine particles (PM 2.5) in it, measured in micrograms per cubic metre and parts per million or ppm units.

The Air Quality Index is measured on particulate matter (PM2.5 and PM10), Ozone (O3), Nitrogen Dioxide (NO2), Sulfur Dioxide (SO2) and Carbon Monoxide (CO) emissions. The higher the AQI value becomes, the riskier the air quality gets.

AQI ranging between 0 and 50 means good air quality while 51-100 means moderate air quality. AQI 101-150 is unhealthy for sensitive groups, such as children, elderly and asthma patients, while 151-200 is unhealthy for all. When the AQI is between 201 and 300, it is considered very unhealthy and beyond 300 is a hazardous level.

Dhaka averaged 284 on the AQI on November 18, peaking to 294, according to data from the Department of Environment. Narayanganj, located beside Dhaka, recorded a hazardous level of 353 on the AQI the same day.

According to Swiss air quality technology company IQAir, Dhaka recorded satisfactory levels, or below 100, in six of the last 11 days of October. But dust particles began rising in November, registering more than 150 on the AQI in the first 10 days of the month and peaking to 225 on Nov 4.

The air quality is at its worst from evening to morning in cities. In Dhaka, the fluctuations can see air quality dropping from unhealthy to hazardous levels in the period.

There is little change to air quality at this time, which often puts Dhaka at the top of the list of cities with most polluted air in the world.

The Department of Environment has warned that the situation would get worse in the days to come.

"In November, the AQI averaged between 180 and 200, but the situation would get even worse in the weeks to follow. Usually, the air quality is at its worst in November and December," said Ziaul Haque, the director of the department's Air Quality Management Division.

He said the sources of air pollution get more active during winter. Due to a low wind speed, the layer of polluted air takes time to move away, and the air never clears out until rain arrives. That is what worries the experts.

A study conducted by Harvard University reveals that air pollution is likely to exacerbate the pandemic crisis.

It found that even a microgram rise of PM 2.5 in every cubic metre of air can raise the fatality rate by 8 per cent.

Randeep Guleria, director of All India Institute of Medical Sciences in Delhi, seconded this finding by saying that air pollution could extend the longevity of coronavirus raising the risks of infection.

Dhaka has recorded more than a fourth of the country's coronavirus cases. Bangladesh has recorded 1,847 new cases of the novel coronavirus in a daily count on Saturday, taking the tally of infections so far to 445,281.

Virologist Nazrul Islam, a member of the national technical advisory committee on COVID-19, said that the elderly and those with more than one underlying conditions would be in the riskiest position if they get infected when air quality is low during winter.

"Air pollution damages the lungs in different ways, and the coronavirus can spread quickly in damaged lungs. Again, it would do a lot of harm to people with weak lungs and comorbidity," he said.

He believes the damage caused by air pollution to other organs would also make people suffer through the pandemic outbreak. He suggested wearing a mask in a city like Dhaka, even if the coronavirus is not there.

"Polluted air is extremely harmful to the lungs of those who are going out after recovering from COVID-19. For those who have suffered a lot of lung damage due to coronavirus, sneezing and coughing will increase once they go out and come on contact with the polluted air after recovery. If the lung infection grows, it could also cause death," said chest disease specialist Professor Dr Mirza Mohammad Hiron.

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