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Is city life getting more hazardous?
October 2004
Last year's SARS outbreak did much to focus attention on health, climate and the urban environment. (See TransScan August 2003 pp 3-4) Since then numerous studies have begun to change perspective on the hazards of urban life - and suggest that in some cases the risks may be increasing.
For example, air pollution now appears to be a greater risk than is usually believed. Research centred on ten developed countries - including Australia - has uncovered what British scientists are describing as an "alarming rise" in pollution-related brain disease.
In Los Angeles, medical researchers have discovered that the city's air pollution is harming development of children's lungs posing a risk that thousands could suffer asthma or emphysema in later life.
A new study by the World Health Organisation centred largely on developing countries, finds that worldwide, polluted air is now one of the main environmental hazards for children - directly responsible for killing three million under the age of five every year.
Meanwhile two international reports have suggested that both global warming and the pressures of human development could create a new wave of infectious diseases.
These predictions have come at a time when the US National Centre for Atmospheric Research is itself predicting that the prolonged heat waves like that seen in Paris last year and in Chicago in 1995 will become more of a norm as the 21st Century progresses.
In New York concerns about the environmental hazards of city life are now being compounded by the decline in private health insurance among the city's urban poor. The fear now is that any outbreak of an infectious disease could have more serious impacts on the wider community.
Across the border the University of Toronto is establishing what it believes to be one of the world's first inter-disciplinary centres to conduct research on urban air quality and its effects on health and climate.
Their aim will be to identify the origin of individual particles on pollution (even if they have arrived from other parts of the world) and determine their health effects. The university's initiative follows a study by Toronto's public health department that the city's polluted air caused 1700 premature deaths each year and 6000 hospital admissions.
The scan also showed:
Brain disease
Air pollution caused by everything from cars to pesticides and packaging are being blamed for a steep rise in brain diseases among people living in 10 developed countries - including Australia. The findings reported in the journal "Public Health" came from an international study of the incidence of brain diseases between 1979 and 1997 in the UK, US, Japan, Australia, Canada, France, Germany, Italy, the Netherlands and Spain.
With the exception of Japan, the incidence of Parkinson's disease and motor neuron disease rose by about 50%. In some places the level of Alzheimer's trebled. According to one of the authors, Professor Colin Pritchard of England's Bournemouth University, the number of neurological deaths mirrored rises in the rate of cancer.
"These are nasty diseases," he said. "People are getting more of them and they are starting earlier. We have to look at the environment and ask ourselves what we are doing."
The researchers believe that the fact Japanese are not suffering to the same degree could be explained by diet. When Japanese live abroad they seem to suffer in the same way as the local population, say the researchers.
Lung function
Research by the University of Southern California has found that teenagers living in the most polluted areas of Los Angeles are nearly five times more likely to have low lung function than others their age living in cleaner areas. The findings, just published in The New England Journal of Medicine, show that those children affected had less than 80% of the lung function expected. The lung damage is attributed to breathing nitrogen dioxide, acid vapour, particulate matter and elemental carbon - most of which come from car exhausts. No one is sure why pollution is impeding lung growth.
City heat
Weather modelling by the US National Centre for Atmospheric Research suggests that as heat-absorbing greenhouse gases intensify they create an unusual atmospheric circulation pattern that has already been observed during heat waves in Europe and North America.
"As the pattern becomes more pronounced, severe heat waves occur in the Mediterranean region, and the southern and western United States," the centre announced in a media statement. "Other parts of France, Germany and the Balkans also become more susceptible to severe heat waves." The centre is now predicting that during the 21st Century heat waves in Chicago, for example, will increase by 25% from 1.66 per year to 2.08. They will also last longer. Instead of five to eight day, they could start lasting eight to twelve days.
