Towards a better understanding of fuzzy sets applied to environmental science

The fuzzy set of a concept is defined by the distribution function of the degree of belief in a certain qualitative parameter, over a range of variation in a quantitative or less-qualitative parameter. The concept may be expressed with different scaling parameters and each parameter on its own, is not necessarily unique. Thus the form of a fuzzy set depends on the choice of scale. In the environmental field, regulators, health authorities, epidemiologists, politicians, environmentalists, engineers and the general public often have different definitions for a concept such as contamination. The only term which is more or less unequivocally understood by all interested groups is the final "risk". Proper definition and scaling of fuzzy sets can provide a common language through which experts from different disciplines can communicate through the entire process of risk assessment. The uncertainty of the input information is propagated in a fuzzy approach and yet the system output will remain fuzzy which can then be translated into either quantitative risk values or qualitative linguistic terms.