Risk assessment is the determination of quantitative or qualitative estimate of risk related to a well-defined situation and a recognised threat. An acceptable risk is a risk that is understood and tolerated usually because the cost or difficulty of implementing an effective countermeasure for the associated vulnerability exceeds the expectation of loss. Risk assessment is involved with some essential steps such as the identification of problem, risk evaluation, and assessment review. Health risk assessment includes variations, such as risk as the type and severity of response, with or without a probabilistic context. Risk assessment consists of an objective evaluation of risk in which assumptions and uncertainties are clearly considered and presented. Part of the difficulty in risk management is that both the quantities by which risk assessment is concerned – potential loss and probability of occurrence -- can be very difficult to measure. Novel Approaches and Their Applications in Risk Assessment is compiled to communicate the latest information on risk assessment approaches and their effectiveness. Presented materials also cover subjects from environmental quality to human health protection.