On 1 and 2 September 1989, the Commonwealth Science Council, acting in cooperation with the Federation of Asian Chemical Societies, UNESCO and other regional and international agencies organised a Symposium on Chemistry and the Environment during the Chemistry International Conference in Brisbane, Australia. The Symposium sought to bring together eminent scientists to identify and discuss major environmental issues of consequence to the Asia-Pacific region having a direct association with chemistry.

This Regional Symposium began as an initiative of Dr G. Thyagarajan, Secretary Commonwealth Science Council, at the 5th meeting of the Asian Coordinating Group for Chemistry (ACGC V) held at Bombay, 8-10 February 1988. Dr Thyagarajan together with Drs Mohinder Singh and J. Webb suggested an Asian initiative in a global perspective, by organising a regional workshop/symposium, dealing with chemical constituents in the environment. This could help in the formulation of effective strategies for containing environmental problems.

Interactive chemical processes are discussed for different levels of our extended atmospheric environment for which the upper boundary has now been pushed to the far reaches of the earth-sun space. Four specific regions are involved.

There are many types of world synoptic data maps, but only within the last few years has serious attention been given to the need for a world geochemical atlas to provide an overview of relative geochemical abundance levels, regional trends and anomalous patterns. Surficial geochemical data are relevant to a wide variety of mineral resource', agricultural, forestry, environmental and health questions as well as many geological problems. Systematic maps can provide an index and a starting point for detailed studies relating to the many applications of geochemistry.

The greenhouse effect, whereby atmospheric CO2 and water vapour prevent the Earth's surface from being totally frozen is likely to be amplified by the anthropogenic emissions of fossil fuel CO2. The global carbon cycle links photosynthesis to the greenhouse effect on all timescales up to millions of years. Major characteristics of the Earth's atmospheric composition, notably the low CO2 and the high oxygen concentrations were created by the evolution of plant photosynthesis.

The planet Earth has a mean surface temperature of 15C, about 30C above the temperature that would exist if there were no infrared-absorbing gases, greenhouse gases, in the atmosphere. These gases include water vapour, carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). The global activities of Man are changing the concentrations of these naturally existing gases and adding additional greenhouse gases which are entirely Man-made.

The combustion of fossil fuels is the main contributor to the increase in the concentration of not only carbon dioxide in the atmosphere but also of oxides of nitrogen and sulphur dioxide. Coal now contributes about 25% to the primary energy generation in the world and its use is projected to increase substantially even as the overall contribution of fossil fuels to energy generation decreases. To mitigate the resulting adverse environmental effects of the increased use of coal, it is imperative that the development and adoption of newer environmentally acceptable technologies for coal conversion is accelerated.

The importance of the ozone layer in the stratosphere has long been known and is only briefly explained here. During the 1970s theories were developed which implicated man-made organic chlorine chemicals in the progressive destruction of the ozone layer. However, until the last few years these theories were in some difficulty because there were no real measurements of ozone being depleted, let alone any depletion being attributable to anthropogenic chlorine.

Our current understanding of acidification in tropical countries is briefly reviewed, and set within the context given by the growing recognition that the tropics are of great importance for the atmosphere globally as a major source of reactive atmospheric chemicals. Key issues are identified, and specific scientific goals for study of tropical atmospheric acidity are outlined, with special reference to relevant parts of the International Global Atmospheric Chemistry (IGAC) program.

Evidence is accumulating that most of the diseases that afflict humanity have their origin in deleterious free radical reactions. These diseases include cardiovascular problems, cancer, inflammatory joint disease, senile dementias, and degenerative eye complaints. The basic process of biological aging is also the result of accumulated free radical damage to the organism.

The concentration of N2O has risen steadily. There are many sources for its formation. It gives rise to NO, NO2 and eventually to HNO3. NO2 along with NO is a common pollutant.

Pesticides are used in all areas of agricultural and animal production to control the various pests that reduce yields and impair the quality of the product. Application methods range from wide-spread treatment of large areas of plant production or large numbers of animals, through specific treatments of isolated commercial crops or handling facilities, to small scale home garden use or individual dosing of animals. All of these uses contribute to the environmental burden of pesticides.

The increasing population, galloping technology and economic development have created awareness of environmental crisis and the need for achieving a balance with nature. In the world today, higher production and consumption of profit oriented commodities are the yardstick of progress. Very often, these pursuits have resulted in the use of air, water and land as free dumping grounds.

The direct and indirect effects of major chemical accidents are amongst the greatest concerns facing the industry, governments, environmentalists and the public in almost every country in the world today. With chemical industrial growth coming to be regarded as barometer of a country's development, and a 1000 or so new chemicals getting added to some 70,000 already in every day use around the world, there is genuine cause for concern in the matter of safety in the design, operation and handling of chemicals and chemical installations.

The possible consequences of global warming have raised so much concern that United Nations has sponsored an effort to develop cooperative mitigation strategies for greenhouse phenomenon. The global temperatures and precipitation with increased levels of carbon dioxide and other greenhouse gases have become a subject matter of deep concern. While actual measurements enable the temperature profile existing at any particular time, modelling has become necessary to predict global warming effects.

There is a range of urban air pollution models currently in use. Rollback and simple box models give crude estimates of the overall emission reductions required to avoid violations of long-term exposure health standards fors low-reacting pollutants. Gaussian plume models are used to predict both short-term and long-term exposures to pollutants arising from motor vehicles and large point sources such as power stations and mills.

For many years, the major environmental problems in the Asia-Pacific region stemmed from the relative lack of development and inadequate infrastructure facilities. In short, poverty itself seemed polluting. Therefore, countries of the region have generally considered economic growth and industrialisation as key development priorities and concern for the protection of the environment has been regarded as of secondary importance.

The International Global Atmospheric Chemistry (IGAC) Program is a core project of the International Geosphere Biosphere Program (IGBP) and seeks to understand quantitatively the chemical and physical processes that determine atmospheric composition. IGAC provides a response to the growing international concern about rapid atmospheric changes and their potential impact to mankind.

While chemistry, over the years, has made immense contribution to human wellbeing, it also has added to some major world problems such as pollution, global warming, acid rain, deforestation, ozone layer depletion and increased risk of cancer. These are currently subjects of global concern. Such concern, although more evident in more advanced countries, but concrete actions, to combat these problems now, are lacking worldwide and at best are patchy.

A panel discussion as the final session of the Regional Symposium was chaired by Dr G. Thyagarajan. He made an introductory statement concerning hazard analysis, limits of detection in the measurement of environmental constituents, scope for regional and international cooperation and possible support from the Commonwealth Science Council.