Air Pollution: Major Health Risk and Killer in Many Cities

The bad old days of grimy, disease-ridden and choked industrial cities are mostly behind us in the developed world. But in developing countries many places are still suffering from life threatening air pollution. By Henrylito D. Tacio

Manilla, 13 April 2011. In the industrialised Meuse Valley in Belgium, during a five-day fog in December 1930, 63 people died.  The signs and symptoms were primarily those caused by respiratory irritants: chest pain, cough, shortness of breath and irritation of the eyes. In London, England in 1952, what were known as “pea-souper” fogs took the lives of at least 3,000 people during the harsh winter when many stoked up coal fires to keep out the cold.

In Europe and most of the developed world, those days are well behind us now, and deaths from urban air pollution are rare. But in new boom cities such as Mumbai, Shanghai, Mexico City and Cairo things are very different; smogs and choking haze is commonplace. But it’s not just the caustic outdoors that can kill – things are often worse indoors in rural areas.

The most common forms of air pollutants are suspended particulate matter (SPM), carbon monoxide, hydrocarbons (which include benzene, xylene, and ethylene dibromide), sulfur oxides, nitrogen oxides, ozone, and residues of the highly toxic tetraethyl lead, a substance added to petrol to enhance its “burning quality.” The most noticeable type of air pollution (since it is readily visible), is smog - a mixture of smoke and fog that is primarily composed of ozone and tiny particulates.

House Odours

Today, the World Health Organization (WHO) has estimated that about 2,500 million people in the world are exposed to excessive levels of air pollution, largely due to burning biomass and coal indoors in ovens that are badly designed and lack proper chimneys. Some 1.9 million additional deaExhaust fumes from diesel powered bikes can kill, but not electric bikes.ths each year are blamed on indoor pollution through suspended particulate matter and another 450,000 deaths are attributed to urban indoor air pollution.

In a joint study the United Nations health agency and the United Nations Environment Program identified Metro Manila as having increasingly serious health problems thanks to air pollution. Nearly 5,000 premature deaths are reported each year from Metro due to respiratory and cardiovascular diseases or “from exposure to poor air quality,” noted the study.

In Manila, like most clogged cities such as Jakarta, the air quality crisis is due to growing vehicle population. The World Bank in a recent report noted that in many cases emissions in are largely from motor vehicles (84 percent), solid waste burning (10 percent), and industries (5.5 percent).  The common use of small 2-stoke engines and cheap, reliable diesel-powered utility vehicles exacerbates the visible emission problem, but the hidden poisons are just as bad.

Deadly Cocktail

“The air in most urban areas typically contains a mixture of pollutants, each of which may increase a person’s vulnerability to the effects of the others,” notes Bernie Fischlowitz-Roberts of the Washington, D.C.-based Earth Policy Institute.

Figure shows the contrast of cities and corresponding populations with air pollution.“Exposure to carbon monoxide slows reflexes and causes drowsiness, since carbon monoxide molecules bind to haemoglobin, reducing the amount of oxygen that red blood cells can carry.  Nitrogen dioxide can aggravate asthma and reduce lung function, and make airways more sensitive to allergens.  Ozone also causes lung inflammation, and reduces lung function and exercise capacity,” she says.

Smaller particulates (10 micrometers in diameter or 1/2,400 of an inch or smaller), can become lodged in the alveolar sacs of the lungs.  These account for a higher number of admissions to hospitals, particularly for respiratory and cardiovascular diseases.  As particulate concentrations in the air rise, so do death rates.

Unlike some pollutants that have threshold levels below which no health effects are seen, ozone and particulates have negative health effects even at very low levels. So no “safe” level of such pollutants exists, and it looks like the problem is not getting better.

Emissions from motor vehicles form 84 per cent of air pollution, according to World Bank.“About 90% of my patients have respiratory illness, and we’re seeing babies as young as two months suffering from asthma,” noted Dr. Miguel Celdran, in a medical journal some years back. “Twenty years ago, this was unheard of.”  Other studies have revealed that heart attacks, life-threatening heart rhythms, and thickening of the blood can also be traced to exposure to air pollution.

As the North Indian Brown Cloud illustrates, effects like this can spread across entire countries. It is something we need to address – and quickly.

How can we do anything about these problems, given the millions of people using vehicles and open fires? As a visitor, take a rickshaw, not a taxi. Don’t go for fancy wood-fired pizzas – go clean power. Don’t rent a smelly, badly maintained motorbike or moped – demand a clean, 4-stroke one instead. And if you can, travel by train too. Rails equals efficient transport.