Environment and health in developing countries
Future trends and emerging issues
Over the next 30 years, most of the world’s population growth will occur in the urban areas of poor countries (10). Rapid, unplanned and unsustainable styles of urban development are making developing cities the key focal points for emerging environmental and health hazards (11).
These hazards include the synergistic problems of urban poverty, traffic fatalities and air pollution. In addition, increased urbanization and motorization and diminishing space for walking/recreation in cities is associated with more sedentary lifestyles and a surge in related noncommunicable diseases(12) (13) (14). Globally, physical inactivity is estimated to be responsible for some 1.9 million deaths each year as a result of diseases such as heart ailments, cancer and diabetes (2). Increased industrial and agricultural production has intensified poorer countries’ production and use of both newer and older chemicals, including some formulations that are banned in other countries. The Organisation for Economic Co-operation and Development (OECD) has estimated that the global output of chemicals in 2020 will be 85% higher than in 1995, and nearly one third of the world's chemical production will take place in non-OECD countries, as compared to about one fifth in 1995. The shift of chemical production from more affluent to poorer settings could increase the overall health and environmental risks arising from the production and use of such chemicals(15).
Already in many developing countries a range of toxic effluents is emitted directly into soil, air and water – from industrial processes, pulp and paper plants, tanning operations, mining, and unsustainable forms of agriculture – at rates well in excess of those tolerable to human health. Along with the problem of acute poisonings, the cumulative health impacts of human exposures to various chemical combinations and toxins can be a factor in a range of chronic health conditions and diseases (16) (17).
At the global level, demand for and unsustainable use of energy resources, (particularly fossil fuels), has placed stress on global ecosystems, including the mechanisms controlling and regulating climate. These, in turn, generate health impacts, e.g. from changed patterns of vector-borne disease to more extreme weather events. Climate change-related health impacts, which currently are responsible for an estimated 150,000 deaths annually, can be expected to increase in the future. Other global environmental changes, such as loss of biodiversity, can have health consequences by increasing instability in disease transmission in animal populations, which are the source of most of the pathogens affecting humans (18). Loss of biodiversity can have other health consequences as well, as a result of the depletion of the genetic resources available for future crop/food production and development of medicines.
The health impacts of environmental risks are heaviest among poor and vulnerable populations in developing countries. For instance, poor coastal populations in developing countries may be among the most vulnerable to sea-level rises and extreme weather events. The poor in developing countries generally have the least access to clean water sources, and those same populations also may be the most directly exposed to environmental risks such as vector-borne diseases and indoor air pollution from solid fuel use. At the same time, poor people also may be the most dependent on natural resources as sources of livelihoods and well-being, and thus be most impacted by unsustainable exploitation or depletion of those resources (16, 19).