In early December 2017, the United Nations Environment Program (UNEP) published Frontiers 2017:  Emerging Issues of Environmental Concern.  The report covers six key emerging issues:  the environmental dimension of antimicrobial resistance; nanomaterials; marine protected areas and sustainable development; sand and dust storms; off-grid solar solutions; and environmental displacement.  The section on nanomaterials addresses nanodimensions — new discoveries about familiar materials; specific forms, applications, and effects; environmental and health exposure to engineered nanomaterials; and applying regulations for health and environmental safety.  According to the report, expanding the research, production, and use of engineered nanomaterials across the world will require “transformative policies to encourage innovation and industrial applications of green chemistry, and more critically, iterative and responsive regulatory frameworks that apply the precautionary principle to assure safety and non-polluting outcomes.”