Air pollution in Dhaka is a new worry in pandemic as winter approaches

Mishuk 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.

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.

AIR POLLUTION LEVELS

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 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 Nov 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.

HOW IT RISKS COVID-19 INFECTION

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 percent.

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.

A thick layer of dust covers the air of Road No. 27 in Dhaka’s Dhanmondi as sewerage repair work drags on. Photo: Mahmud Zaman Ovi

"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.

"The air particles from polluted air can create a series of complications if they enter our lungs while breathing," said Dr Hiron, a former director of National Institute of Cardiovascular Diseases and Hospital and the president of Chest and Heart Association of Bangladesh.

Mohammad Mushtuq Husain, a public health expert, feels that more research is needed to figure out the dangers of exposure to polluted air amid the coronavirus outbreak.

"Air pollution messes with the respiratory organ's immune system and raises the risks of diseases related to it. And if someone contracts the coronavirus on top of that, there will be complications," he told bdnews24.com.

Rainfall is low to none during winter which puts away the possibility of naturally occurring air-cleansing in the season. And for Dhaka, this is an even more hazardous issue, Mushtuq Husain believes.

Those, who are more than 50 years old, have comorbidity, hypertension, cancer, asthma, inflammation in the respiratory tract, overweight or kidney complications should be on guard during winter, he said. He urged the government to take steps to keep the pollution in check.

"Vehicles increase air pollution. The authorities must unfit vehicles. If the city corporation sprays water on both sides of the road twice a day, the pollution will lessen. We will not be able to curb pollution if we cannot control construction work and digging," Husain said. He also advised people to keep their masks on outdoors.

CURBING POLLUTION

Environmentalists see air pollution as an additional challenge amid the pandemic crisis.

The health services sector is under heavy stress as air pollution is increasing the virus fatality rate, said Lauri Myllyvirta, the lead analyst of Finland's Centre for Research on Energy And Clean Air.

In a research article presented at a webinar organised by Bangladesh Poribesh Andolon in June, he said that thousands of people had already fallen victim to air pollution both directly and indirectly.

Dr Abdul Matin, executive vice president of BAPA, said, "It is not possible to lower the air pollution while keeping the factories running without ETPs [effluent treatment plants]. The government doesn't compel them to set up ETPs. Even government factories do not have ETPs."

"The government needs to get to the bottom of this. The main sources of air pollution need to be shut down. And the city has to be cleaned in a disciplined manner."

Ziaul Haque of the Air Quality Management Division mentioned different government initiatives to curb pollution.

"We demolished 700 brickfields last year. We'll do the same this year. We are promoting blocks instead of bricks. These brickfields increase air pollution," he said, adding that the government has sent a notice to its agencies asking them to replace bricks with blocks in construction of all government establishments.

The authorities will also try to control the dust particles produced by construction sites by using sprinklers, he said. Uncovered trucks carrying bricks and sand will not be allowed into Dhaka, he said.

"The construction sites must be covered as well, or we'll send in magistrates to punish the owners."

"Pollution from the vehicles can be reduced by removing those emitting black smoke from the roads. We've discussed this with the police and BRTA."