Global Environment Outlook 3 (GEO 3)

2 1 0

STATE OF THE ENVIRONMENT AND POLICY RETROSPECTIVE: 1972–2002

UNEP, Angelo Dotto, Italy, Still Pictures

Atmosphere

Global overview Over the past three decades, anthropogenic emissions of chemical compounds into the atmosphere have caused many environmental and health problems. Some chemicals, such as chlorofluorocarbons (CFCs), are produced deliberately and end up in the atmosphere by accident from equipment or goods. Others, such as sulphur dioxide (SO 2 ) and carbon monoxide (CO), are unavoidable by-products of burning fossil fuels. Urban air pollution, acid rain, contamination by toxic chemicals (some of them persistent and transported over long distances), depletion of the stratospheric ozone layer and changes in the global climatic system are all important environmental threats to ecosystems and human well- being. Air pollution and air quality The World Health Organization (WHO) lists six ‘classic’ air pollutants: CO, lead, nitrogen dioxide (NO 2 ), suspended particulate matter (SPM) — including dust, fumes, mists and smoke — SO 2 and tropospheric ozone (O 3 ) (WHO 1999).

The burning of fossil fuels and biomass is the most significant source of air pollutants such as SO 2 , CO, certain nitrous oxides such as NO and NO 2 (known collectively as NO x ), SPM, volatile organic compounds (VOCs) and some heavy metals. It is also the major anthropogenic source of carbon dioxide (CO 2 ), one of the important greenhouse gases. Between 1973 and 1998, total energy supply increased by 57 per cent (see graph opposite), the majority provided by oil, natural gas and coal with nuclear and hydropower and other renewable resources playing a minor role (IEA 2000). The fuels used vary from region to region — for example, natural gas dominates in the Russian Federation, while coal provides 73 per cent of the energy consumed in China (BP Amoco 2000). Biomass is an important source of energy in the developing world and is the main source of indoor air pollution in such countries (Holdren and Smith 2000). Acid precipitation has been one of the most important environmental concerns over the past decades especially in Europe and North America (Rodhe and others 1995), and more recently also in China (Seip and others 1999). Significant damage to forests in Europe became a high priority environmental