Online Desk : Raziur Rahman has just recovered from Covid-19 after staying a week at a government hospital.

He has asthma and doctors advised him to stay away from dust and try not to catch a cold because these would aggravate his respiratory problems.

But the air in Dhaka deteriorates substantially during winter and so does the health of Raziur and his 7-year-old son Razin Rahman, who suffers from a cold and persistent cough throughout winter.

Their predicament is shared by thousands as the Department of Environment (DoE) found the air quality starting to dip from October.

According to the Air Quality Index monitored by the DoE`s Clean Air and Sustainable Environment (CASE) project, the average AQI in Dhaka was 117.4 in October and 194 in November.

An AQI value between 0 and 50 is considered satisfactory. Air pollution poses little or no risk at such levels. A value between 151 and 200 means everyone, especially a member of sensitive groups, is likely to experience health effects.

In Gazipur, the AQI was 120 in October and 178 in November. In Narayanganj, it was 124 in October and 173 in November.

Globally, an AQI from 201-300 is categorised as "very unhealthy", and 301-500 "extremely unhealthy".

Dust, construction works, fog, vehicle emissions, brick kilns, trans boundary pollution, burning of trees and leaves are the major causes of air pollution in Bangladesh.

"From November 10, the situation has been getting worse. Compared to this time last year, the situation is bad. Even though the educational institutions are closed, the AQI is around 10 percent higher than it was a year ago," Prof Mohammad Kamruzzaman Majumder, director of the Center for Atmospheric Pollution Studies at Stamford University, told The Daily Star yesterday.

A Dhaka University study released in November last year, found the air in surveyed schools to be hazardous for children. Bangladesh remains to be among the countries with the poorest air in the world in winter.

The country witnessed fresh air and clear skies during the lockdown this year, but it seems like the pollution has come back with a vengeance.

The World Health Organization (WHO) said cities with higher levels of air pollution should boost their preparedness against the coronavirus.

Bangladesh is already witnessing a surge in Covid-19 cases even though the winter has yet to set in. Poor quality air causes inflammation in the lungs, making people more vulnerable to respiratory diseases like Covid-19.

"Poor air quality is a threat to anyone with respiratory problems. And if someone with respiratory problems gets infected with coronavirus, they will be in great danger," IEDCR Consultant Prof Mushtuq Hussain told The Daily Star.

Researchers at Harvard University associated an increase of only one microgram per cubic metre of air in fine particulate matter called PM 2.5 with an 8 percent increase in Covid-19 morbidity.

Last year, Dhaka`s air remained "very unhealthy" and "extremely unhealthy" for 197 days, according to AQI.

Globally, around 93 percent percent of the children aged 15 and below, are exposed to PM2.5 levels above WHO air quality guidelines, putting their health and development at serious risk, says a 2018 report of the WHO.

According to WHO, household and outdoor air pollution affect neurodevelopment and cognitive ability, damage children`s lung function, and put children at greater risk of chronic diseases later in life.

In low- and middle-income countries, air pollution causes more than half of acute lower respiratory infections in children aged five and below.

Air pollution led to 1,73,500 deaths in Bangladesh last year, says a global report as experts find the country`s air becoming increasingly poisonous in the absence of effective measures to control the release of pollutants.

The report titled State of Global Air 2020 identifies air pollution as the fourth major mortality risk factor worldwide, surpassed by high blood pressure, tobacco use, and poor diet.

It added that air pollution accounted for 10,500 neonatal deaths in Bangladesh. Of the deaths 62 percent is attributable to household air pollution.

POOR AIR QUALITY IN SCHOOLS
The Dhaka University study titled Health Impact of Gaseous Air Pollutants from Different Schools in Dhaka was conducted by chemistry teachers and students. They measured air pollutants at 10 schools in different locations between April and November 2018 and found high levels of nitrogen dioxide and carbon dioxide both outside and inside classrooms.

The schools were in Mugda, Shukrabad, on DU campus, Khilgaon, Motijheel, Maniknagar, Ahmedbagh, Chankharpool, Wari and Badda areas. The air was monitored between 7:30am and 11:30am.

The school in Maniknagar had the worst air, with a quotient of 1.92. A hazard quotient over 1 is deemed dangerous to health, according to the United States Environmental Protection Agency. The lowest hazard quotient was found in the school in Khilgaon with 1.15.

Experts said that the study points out an urgent need to contain air pollution, especially near schools.

"This report highlights that exposure of children to toxic compounds in the air not only occurs outdoors but also inside schools and classrooms. More research on the health effects of such exposure over long periods is urgently needed," DU Chemistry Prof Abdus Salam said.

Children are particularly at risk of developing asthma, especially if they live near busy roads, he said.

WHO says children are more vulnerable to air pollution because they breathe more rapidly than adults and absorb more pollutants.

The study also found that outdoor pollution influenced indoor air quality and carbon dioxide was at higher levels in the morning. Other major air pollutants with health effects are particulate matter (PM), ozone, nitrogen dioxide, and sulphur dioxide.

"The major cause of increased indoor NO2 concentration is the exhaust fumes from vehicles," said Prof Salam. "Policymakers should act on the matter promptly and initiate some action to reduce traffic congestion and the number of cars on the roads."

The researcher said none of the schools had air purifiers or masks to protect the students.

DoE`s Air Quality Control Wing Director Ziaul Haque said smoke and fog create smog in the morning hours in winter.

"This is very harmful to human health and certainly for children who go to school at the time," he said.

He added that his department has been monitoring brick kilns and construction sites, and spraying water in different places in the city to contain air pollution.

"Containing air pollution is not possible by a department or ministry alone. It requires a coordinated effort and every stakeholder has to step forward."

(The Daily Star)