June 19, 2014
There’s Something In The Air
Way back when I was a small boy, the air seemed to be constantly full of smoke and there were frequent episodes of dense “smog.” The word is a combination of two other words — smoke and fog — and describes a choking mixture with almost zero visibility at times. This was not a uniquely British problem, of course. Many places around the world were, and still are, badly affected. In the UK, the smog was mainly caused by the generalized use of coal for domestic heating and industrial production.
It’s hardly a new problem. As long ago as 1306, King Edward I had to ban coal fires in London. Nowadays, smog is more often associated with emissions from motor vehicles. A modern variant is “photochemical” smog, which occurs when sunlight causes reactions with airborne chemical pollutants.
Whatever the cause, one thing is sure and certain. Smog is bad for people. Smog can kill. But air pollution is not always visible and the unseen pollution is just as hazardous. The results of a new survey by the World Health Organization (WHO) has highlighted the problem and lists the world’s cities according to their levels of air pollution. It is not a pretty picture.
Of all the alarming statistics the report throws out, perhaps the most worrying is that only 12 percent of the world’s city-dwelling population breathes what WHO defines as clean air. In addition, approximately half of all those who live in cities experience levels of air pollution that are well over double the recommended safe limits. The implications for the long term health prospects of billions of people worldwide are enormous.
WHO’s figures also show that the situation is getting worse. This is due to our reliance on fossil fuels, transport, energy inefficiency, and the use of biomass for cooking and heating. In another report in April, WHO estimated that 3.7 million people died in 2012 as a result of outdoor air pollution. That figure is bad enough, but says nothing about the debilitating effects of bad air on the living.
Air quality was measured by assessing the amount of particulate matter. Two measures were used — PM2.5 (particles less than 2.5 micrometers in diameter) and PM10 (10 micrometers). They are expressed as ug/m3, which indicates the amount of PM2.5 or PM10 in a cubic metre of air. Of the two, PM2.5 is considered the more dangerous, as smaller particles enter the lungs more easily. London, for instance, has a ug/m3 figure of 16 — that’s 1.6 times the recommended maximum.
Using these measures, the survey found that the Indian city of Delhi was the world’s worst city for air pollution. With a horrifying ug/m3 figure of 153, Delhi was one of the four Indian cities that topped the list. There are six Indian cities in the top 10, three from Pakistan, and Khoramabad in Iran completes the top 10 in eighth place. Delhi’s prospects are not good when there are an extra 1,400 new vehicles appearing on its roads every single day. Not surprisingly, India has one of the worst records for deaths from chronic respitratory diseases.
It’s a situation that requires action on a global scale. As WHO puts it, “We cannot buy clean air in a bottle, but cities can adopt measures that will clean the air and save the lives of their people.”
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