Nigeria's Onitsha, the commercial nerve centre of South East Nigeria has been listed as one of the world's Most Polluted Cities along with Zabol in Iran.
Read the story as reported in The Guardian:
The new WHO database of worldwide air pollution measures it in two different ways, and as a result two cities – one in Iran and another in Nigeria – can lay claim to the unenviable title of world’s most polluted city.
It all comes down to which minute particles, or particulate matter (PM), in the air are being measured. These particles are between 2.5 and 10 microns in diameter, roughly 30 times smaller than the width of a human hair.
The coarser PM10s include dust stirred up by cars on roads and the wind, soot from open fires and partially burned carbon from the burning of fossil fuels like coal, oil and wood. The particles are small enough to be inhaled deep into the lungs.
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But the ultra-fine particles known as PM2.5s can only be seen with microscopes and are produced from all kinds of combustion. These are small enough to get from the lungs into the blood supply and are possibly more deadly because they affect the cardiovascular system.
Many cities in developing countries traditionally monitor only PM10s. But increasingly PM2.5 pollution is seen as the best measure of how bad air pollution is for health. Richer countries usually have higher levels of PM 2.5s, while low income countries have higher levels of PM10s. Both, says the WHO, are deadly.
Onitsha: highest for PM10s
In 2013, two people died of heat exhaustion after a six-hour gridlock on the city’s bridge over the river Niger. Cars and trucks on the main road to Lagos belch fumes from burning low-quality diesel, and the air often stinks of burning waste from rubbish dumps, the smoke from old ships on the river and discharges from the metal workshops.
But people did not expect Onitsha in Anambra state on the eastern bank of the mile-wide river Niger, to be named the most polluted in the world.
According to the WHO, an air quality monitor there registered 594 micrograms per cubic metre of microscopic PM10 particles, and 66 of the more deadly PM2.5s. Onitsha’s figures are nearly twice as bad as notoriously polluted cities such as Kabul, Beijing and Tehran and 30 times worse than London.
“We know pollution is very bad here. But this city must be much better than Lagos,” said Solomon Okechukwa, a sceptical Anambra state official, on Wednesday.
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But Onitsha, say academics, is a textbook example of the perils of rapid urbanisation without planning or public services creating a sustained pollution assault on its water and air.
As a tropical port city which has doubled in size to over 1 million people in just a few years, it is frequently shrouded in plumes of black diesel smoke from old ships; it has no proper waste incineration plants; its construction sites and workshops emit clouds of dust and its heavy traffic is some of the worst in Nigeria.
A recent study of Onitsha’s water pollution found more than 100 petrol stations in the city, often selling low-quality fuel, dozens of unregulated rubbish dumps, major fuel spills and high levels of arsenic, mercury, lead, copper and iron in its water. The city’s many metal industries, private hospitals and workshops were all said to be heavy polluters emitting chemical, hospital and household waste and sewage.
Story culled from theguardian.com
Photo credit @Austynzogs on twitter
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