Poorest are worst affected by urban expansion
Rapid expansion of cities has a greater negative impact on poorer inhabitants who cannot afford to move to the outskirts where the air is cleaner, according to a recent study which examined the effects of urban sprawl.
Urban sprawl is characterised by rapid, expansive growth of a town or city, which is often driven by uncontrolled development of suburbs at the edges. During this two-part study, the researchers developed a computer model that simulated the effects of urban sprawl. The Ruhr area in Germany was used as the model region. This area contains several cities and has a total population in excess of 5.5 million.
The researchers simulated the associated changes in the affected towns and cities, including: the change in land use, redistribution of people and employment, traffic, atmospheric pollution and the relative human exposure to that pollution. Basing their study on established patterns of urban development, the researchers simulated what would happen if
12 per cent of the population moved to city edges. The researchers discovered that, as predicted, urban sprawl increased traffic, especially car use. Private car use increased more than public transport use as people moved further from their place of work and into more remote areas. According to the researchers, the daily passenger traffic kilometres increased by 16.7 per cent, compared with estimated levels1 in the existing urban area of the Ruhr region. This in turn, increased overall energy consumption and levels of air pollution.
However, the study suggested that some sections of the population are exposed to higher levels of pollution than others. Residents who move out to more remote areas at the edge of the city have better quality air, and are exposed to fewer pollutants. However, this is at the expense of those who remain in central areas, who are exposed to higher levels of pollution, derived for example from the increase in traffic. Air pollution is responsible for a number of health problems, notably respiratory diseases.
The researchers point out that the choice to move to the green periphery of a city is typically only available to wealthier members of society. They conclude that urban sprawl benefits the air quality for the rich at the expense of