Không chắc chắn trong A. Đánh giá rủi ro không chắc chắn trong Bốn bước đánh giá rủi ro 1. Xác định nguy hiểm 2. Đánh giá đáp ứng liều 3. Tiếp xúc với đánh giá 4. Mô tả đặc tính rủi ro III. Xác định không chắc chắn biến đổi A. B. Sự không chắc chắn C. khác Khung IV. Cách tiếp cận EPA để biểu không chắc chắn Xác định mối nguy A. B. Liều lượng, đáp ứng Đánh giá C. Tiếp xúc với đánh giá Mô tả đặc tính rủi ro D. V. Các phương pháp được. | CHAPTER 7 Characterization of Uncertainty Steave H. Su Robert M. Little and Nicholas J. Gudka CONTENTS I. Introduction II. Uncertainties in Risk Assessment A. Uncertainty in the Four Steps of Risk Assessment 1. Hazard Identification 2. Dose-Response Assessment 3. Exposure Assessment 4. Risk Characterization III. Defining Uncertainty A. Variability B. Uncertainty C. Other Frameworks IV. The EPA Approach to Addressing Uncertainty A. Hazard Identification B. Dose-Response Assessment C. Exposure Assessment D. Risk Characterization V. Recommended Methods to Characterize Uncertainty A. Hazard Identification B. Dose-Response Assessment C. Exposure Assessment 1. Uncertainty 2. Variability 3. Techniques to Separate Characterization of Uncertainty and Variability D. Risk Characterization 1999 by CRC Press LLC VI. Communication of Uncertainty in Risk Assessment VII. Conclusion Bibliography As far as the laws of mathematics refer to reality they are not certain and as far as they are certain they do not refer to reality. Albert Einstein 1879-1955 I. INTRODUCTION Uncertainty in risk assessment denotes the lack of precise characterization of risk. While the potential for health risks due to exposure to environmental pollutants is known the level of risk cannot be precisely ascertained it can only be estimated. For example the estimates of excess cancer risk from exposure to volatile organic chemicals VOCs emitted from building materials can be highly uncertain. This uncertainty has many origins the emission rates of VOCs are difficult to characterize the individual s time in the building is variable and the toxic potentials of the chemicals are uncertain. For this example the estimated risk can differ by orders of magnitude under different assumptions of exposure and physicochemical parameters. Such degree of uncertainty in any risk assessment is not surprising. Under the current risk assessment methodology the estimated risks are expected to contain uncertainty spanning an .
