This Technical Report (TR) has been developed by CEN/TC 350/WG 1 and WG 3 to provide a clear and structured view on the relevance, robustness and applicability of a predefined set of additional impact categories and related indicators for the assessment of the environmental performance of construction works, construction products and building materials.The TR describes the evaluation criteria that are used to determine, for these impact categories, the suitability of indicators and calculation method(s) for inclusion in the standards EN 15978 and EN 15804 (or other CEN/TC 350 standards as appropriate) in terms of their:a)relevance to:1)the environment,2)construction works,3)construction products, and4)EU policy;b)scientific robustness and certainty; andc)applicability of the impact assessment method(s).The additional impact categories examined in the TR are:-human toxicity and ecotoxicity;-particulate matter;-land use;-biodiversity;-water scarcity; and-ionizing radiation.Because EN 15978 and EN 15804 are founded on a life cycle approach, the impact categories, indicators and methods reviewed are predominantly based on their potential suitability for application in LCA. In relation to some of the areas of concern, however, where LCA methods might not be sufficiently robust or developed, some non-LCA based indicators and methods are also considered.Due to the scope of LCA used in the EN 15804 and EN 15978, impacts to users of buildings due to direct exposure to harmful emissions fall outside the scope of this TR. This falls under the scope of CEN/TC 351. Important information related to this aspect found during the development of this TR, is however mentioned in the TR.Uncertainty is an important issue in LCA. General assessment of the uncertainty related to impact assessment models is considered in the evaluation framework of this TR. However, the TR does not lay down a maximum uncertainty level to be considered acceptable in the context of the CEN standards EN 15804 and EN 15978, nor does it provide exact figures on uncertainties.Annex A of the TR provides a description of options that may be considered for incorporating selected impact categories/indicator in the standards EN 15978 and EN 15804.The TR recognizes and takes account of:-the work done by the European Commission, Joint Research Centre (EC-JRC), in the development of the International Reference Life Cycle Data System (ILCD) Handbook Recommendations,-other reports and scientific studies into the methods and application of the indicators reviewed,-findings of specific activities connected with this work such as of the CEN/TC 350 Workshop, held in Brussels on 24-25 June 2014.