The Good Air Lady
The Good Air Lady
talks about what you breathe
indoors and out

Megacities Air Pollution

There's lots of controversy about air quality and how to improve it, but there isn't much question that megacities air pollution is out of hand and must be fixed. Part of the problem is that the pollution doesn't stay at the source, it is mixed by air currents so that the pollution is spread around the world. Everyone has to get involved in helping create clean air and reducing air pollution.

The Global Environment Monitoring System (GEMS) was created in 1974 by the World Health Organization and The United Nations Environment Programme (UNEP) to monitor air pollution in large cities of the world. The network monitors levels of suspended particulate matter concentration, lead, carbon monoxide, nitrogen dioxide, sulfur dioxide, and ozone in the air.

UNEP defines a "megacity" as an urban agglomeration with a population of 10 million or more. There were 24 megacities worldwide in 1997. (UNEP also identified 59 "supercities" with populations of 5 million to 10 million, and growing.)

Densely packed populations in large urban areas generate extreme levels of air pollution. In megacities Beijing, Cairo, Jakarta, Los Angeles, Mexico City, Moscow and Sao Paulo, three or more of the five substances monitored by GEMS exceed WHO guidelines by more than a factor or two.

The health consequences air pollution are both obvious and accepted nonchalantly by residents of megacities. In Mexico City, for example, joggers wear face masks in vain efforts to avoid chronically dangerous levels of ozone. Paradoxically, they endanger their health while trying to improve it. It is not uncommon to see schoolchildren wearing face masks while playing. Studies suggest that children living in neighborhoods with the worst air could suffer permanent alterations to cells in their nose and throat linings which could lead to cancer later in life.

Approximately 20 to 30 percent of all respiratory diseases appear to be caused by air pollution. Over one million of Mexico City's 18 million residents suffer permanent breathing difficulties, headaches, coughs and eye irritations.

Perhaps the deadliest air pollution found in megacities is Suspended Particulate Matter (SPM). U. S. studies indicate significant mortality correlation with low levels of SPM. There is concern that SPM-related mortality rates are much higher among megacities in developing nations whose medical infrastructure is less able to cope with SPM-caused disease and illness.

Developing nations make fewer efforts to reduce air pollution, resulting in much higher levels of air pollution in their megacities than in their counterparts in developed nations. The only megacities in which SPM levels are within WHO guidelines are London, Tokyo, and New York City. High levels of lead banned from gasoline in developed nations - are still found in the air of megacities Cairo and Karachi and, to a lesser extent, in Bangkok, Jakarta, Manila and Mexico City. Lead levels in African cities like Cairo, Cape Town and Lagos, or are up to ten times those of the typical European cities.

Asian megacities pose enormous air pollution problems. More than half of the world’s population lives in urban areas in Asia. Air pollution in Asian megacities such as Beijing, Delhi, and Jakarta has worsened considerably under pressures from population growth, industrialization, and increased automobile use.

The Air Pollution in the Megacities of Asia (APMA) project was launched in November, 2000, as a follow-up to the WHO/UNEP GEM program. It aims to increase the capacity of governments and city authorities to deal with urban air pollution issues by developing regional action plans and establishing an urban air pollution network for Asian megacities. The sixteen cities included in the APMA project are Bangkok, New Delhi, Beijing, Osaka, Calcutta, Seoul, Chongqing, Shanghai, Guangzhou, Singapore, Hong Kong, Taipei, Kathmandu, Tokyo, Manila, and Mumbai.

The devastating history of air pollution in developed nations is poised to repeat itself in many more developing nations. It is essential to codify the lessons learned from past mistakes into transnational best practices to prevent a second, much more perilous wave of destructive air pollution in the world's increasing population of megacities.

Though megacities air pollution problems haven't been solved, action is being taken. Education of the people in those cities is part of the solution, but so is correcting the problems created by companies involved in transportation, fuel, and manufacturing. It's going to take lots of attention and effort by everyone to clean up the air in the megacities.