Changing environments, changing health threats

The outcome of new indicators developed by the World Resources Institute (WRI) are a series of maps which portray the geographic distribution of various environmental threats to health. These maps suggest both the level and type of environmental risks individual countries face. Because environmental threats to health emanate from many sources and vary dramatically by region and level of economic development, WRI calculated risks to health separately for developed and developing countries.

In these countries, environmental threats to health are broad, stemming from both biological risks associated with poverty and chemical risks associated with industrialization. Threats in the former category include inadequate water and sanitation and exposure to vector-borne diseases that thrive in tropical climates. In some countries, the effects of ambient air pollution, from both onventional air pollutants and lead in gasoline, are compounded by the burning of smoky fuels indoors.The effects of pollutants and infectious agents are exacerbated by inadequate nutrition, as will be discussed later. For these reasons, the developing country index examines risks in three categories: air, water, and food. Some countries, such as poorer countries in Africa, may face high risks from indoor air pollution but low risks from outdoor air pollution; other countries such as India and China face both. In areas where these threats coincide with poor nutrition and/or water-related diseases, the environmental risks to health are likely to be high. Generally, countries in Africa and parts of Asia face the highest environmental threats to health. In much of Central and South America, environmental risks are moderate to low. Many of these countries have expanded water and sanitation coverage in recent years and have also removed lead from gasoline. (For details on how these indexes were constructed and additional data on each country, see Indicators of Environmental Threats to Health and the Environmental Risks to Human Health: New Indicators.)

In most developed countries, by contrast, environmental threats stem primarily from industrial pollution – either conventional air pollutants, air toxics, or hazardous chemicals. Because data on chemical releases or exposures are generally lacking or of poor quality, WRI’s preliminary indicators for developed countries focus solely on air pollution. Countries are ranked both according to their potential exposure to polluted ambient air and their potential exposure to lead in gasoline.

This map shows countries where the populations face an elevated risk from potential exposure to air polluted with lead from gasoline. (For data on country-level risk of exposure to outdoor air pollution, see Environmental Risks to Human Health: New Indicators.) The former Soviet Union and parts of Eastern Europe face high risks from exposure to lead in gasoline. Perhaps more unexpected, France, Germany, the Netherlands, and the United Kingdom, among others, also face high risks because of their continued use of leaded gasoline and dense urban populations.

As with any indicator, a number of caveats are warranted. First, these indicators do not measure adverse health effects; rather, they identify where risks are high, based on exposure to harmful agents. It is not possible to translate the risks identified in these indicators into estimates of excess sickness or death. Even so, one can safely assume that lower risk generally translates into better health. Nor do these indicators capture variations in risks within countries, which are known to be substantial, as will be discussed later in this chapter.

Shortcomings aside, the developing world indicator does serve as a rough guide to the severity and types of potentially harmful environmental exposures people face in various countries. Many of these exposures and their adverse effects can be prevented through policy actions at the local, national, or international level. As the indicator suggests, countries need not be wealthy to reduce environmental threats to health. Many actions can improve both environmental quality and public health for relatively low cost. These and other preventive policies are the focus of Improving Health Through Environmental Action.

World Resources 1998-99 examines the myriad ways in which environmental conditions, and especially environmental change, affect human health. Here “environment” is defined as the physical, chemical, and biological setting in which people live – in other words, the condition of the air, water, soil, and climate. Not included are the social environment; lifestyle and behavioral choices such as smoking, alcohol consumption, and diet; or the workplace. Although these factors have enormous influences on health, they are beyond the scope of this report.

Environmental hazards to health fall into two broad categories. The first is a lack of access to essential environmental resources – chief among them sufficient and clean water, food, shelter, fuel, and air. The second broad category is exposure to hazards in the environment. These hazards include biological agents – microorganisms such as bacteria and viruses and parasites – that contribute to the huge global burden of infectious diseases. Biological agents are implicated in diseases from diarrhea to acute respiratory infections, to malaria, to ulcers, and to some cancers. Also included are noxious chemical and physical hazards in the environment. Some pollutants, such as pesticides and industrial solvents, are created by human activities. Others, including arsenic or ultraviolet (UV) radiation, occur naturally in the environment, although exposure can be exacerbated by human activities. These pollutants can undermine health in various ways, by contributing to cancer or birth defects or perhaps by damaging the body’s immune system, which renders people more susceptible to a variety of other health risks.

In the past several years, scientists have become increasingly aware that environmental changes, locally and regionally, as well as globally, can exacerbate both types of environmental health problems. Development projects such as the building of dams and roads can displace local populations, for instance, altering agricultural practices, undermining nutrition, and increasing the spread of infectious diseases. On a global scale, greenhouse warming threatens to render certain land unsuitable for agriculture or even habitation and may also increase the range of disease-carrying mosquitoes.

World Resources 1998-99 is concerned not just with today’s environmental health threats, which are clearly substantial, but also with the extent to which human activities are altering the environment and what those changes portend for human health. Environmental change is an inevitable consequence of economic development and people’s desires to improve their quality of life. In pursuit of a better life, forests and grasslands are converted to farms, homes, and commercial spaces; raw materials are extracted for energy and commerce; and waterways dammed and diverted. Pollutants are dispersed into air, water, and soil. In the process, the face of the planet has been transformed.

Without question, the benefits of economic development have been enormous. Economic growth and social progress of the past several decades have ushered in an era of untold prosperity and health in most regions of the world. Globally, per capita gross domestic product (GDP) has jumped from US$2,257 to US$3,168 in the past 25 years; life expectancy has climbed from 57.9 to 65.6 [15]. Yet, economic development has had unintended consequences as well – namely, environmental degradation and increased threats to human health. Unless consideration is given in advance to the consequences of economic growth – especially the rapid growth now underway in many parts of the world – environmental threats to human health will surely intensify, undermining the gains in welfare that development typically brings.

References and notes

15. United Nations (U.N.) Population Division, World Population Prospects, 1950-2050 (The 1996 Revision), on diskette (U.N., New York, 1996), using median estimates of five-year intervals.