As a national-level institution specialized in environment and health, National Institute of Environmental Health (NIEH, China CDC) serves as a center for operational and technical guidance. Centering around the four-in-one functions of disease control,emergency response, scientific research and education, NIEH mainly carries out the investigation, surveillance and scientific research of population exposure, health effects and health impact of environmental risk factors, as well as disinfection and infection prevention; it also implements the research and development, evaluation and promotion of technology and methods associated with environmental health, disinfection and infection control, participates in health emergency responses and assessment of unexpected environmental pollution, natural disasters and infectious disease outbreaks, launches assessment and early warning of environmental health impacts, risk assessment and information exchanges, undertakes the environmental health, disinfection and infection control, as well as related laboratory quality control and standard management, assumes the tasks of medical education, postgraduate training and technical guidance for local disease control agencies and conducts international cooperation and exchanges in the field of environmental health.