This volume is part of a series on global estimates of disease burden caused by environmental risks, and guides for estimating the disease burden from specific risks at country or local level. This Environmental Burden of Disease (EBD) series responds to the need to quantify environmental health risks as input to rational policy making. Quantification of disease will provide information on the health gains that could be achieved by targeted action on protecting against specific environmental risks to health. An introductory volume (No. 1 of the series) provides further details on methods used for such quantification.