Nuclear hazards exist globally.

Acute health effects such as skin burns or acute radiation syndrome can occur when doses of radiation exceed certain levels. Low doses of ionizing radiation can increase the risk of longer term effects such as cancer.

Radiation is energy that travels in the form of waves or particles, and is part of our everyday environment. People are exposed to radiation from cosmic rays, as well as to radioactive materials found in the soil, water, food, air and also inside the body. Human-made radiation sources are widely used in medicine, industry, and research. There are two types of radiation: ionizing and non-ionizing radiation.

Non-ionizing radiation encompasses both natural and human-made sources of electromagnetic fields. Electrical power supplies and appliances are the most common sources of low frequency electric and magnetic fields in our living environment. Everyday sources of radiofrequency electromagnetic fields include telecommunications, broadcasting antennas and microwave ovens. Exposure to intense, direct amounts of non-ionizing radiation may result in damage to tissue due to heat, however this is not common and mainly of concern in the workplace for those who work on large sources of non-ionizing radiation devices and instruments.^{3 3}CDC: Radiation StudiesX

Ionizing radiation is a type of energy released by atoms in the form of electromagnetic waves or particles. People are exposed to natural sources of ionizing radiation, such as in soil, water, and vegetation, as well as in human-made sources, with the medical use of ionizing radiation being the highest contributor to people’s exposure (e.g. diagnostic radiology, image-guided interventions, nuclear medicine and radiotherapy). As the use of ionizing radiation increases, so does the potential for health hazards if not properly used or contained. 

People can be exposed to ionizing radiation at home or in public places (public exposures), at their workplaces (occupational exposures), or in a medical setting (as are patients, caregivers, and volunteers). Exposure to ionizing radiation can be classified into 3 exposure situations:

1. Planned exposure situations result from the deliberate introduction and operation of radiation sources with specific purposes, as is the case with the medical use of radiation for diagnosis or treatment of patients, or the use of radiation in industry or research.
2. Existing exposures are where exposure to radiation already exists, and a decision on control must be taken – for example, exposure to radon in homes or workplaces or exposure to natural background radiation from the environment.
3. Emergency exposure situations result from unexpected events requiring prompt response, such as nuclear accidents or malicious acts.

Radiation exposure may be internal or external, and can be acquired through various exposure pathways:

• Internal exposure to ionizing radiation occurs when a radionuclide is inhaled, ingested or otherwise enters into the bloodstream (for example, by injection or through wounds). Internal exposure stops when the radionuclide is eliminated from the body, either spontaneously (such as through excreta) or as a result of a treatment.
• External exposure may occur when airborne radioactive material (such as dust, liquid, or aerosols) is deposited on skin or clothes. This type of radioactive material can often be removed from the body by simply washing.

• Those exposed to nuclear hazards at work (e.g. miners)

Increasing frequency of extreme weather events is likely to increase the risk of nuclear disasters.

Meteorological Services

Following a nuclear accident, weather patterns can affect the size and direction of the affected area. National meteorological services have an important contribution to make in the response to all cross-border environmental emergencies because of their 24/7 monitoring and operational activities and their links to regional and global information systems and emergency services.^{4 4}WMO Addresses Ministerial Conference on Nuclear SafetyX

In addition, some national meteorological services are designated to provide real-time technical capacity to the World Meteorological Organization as it assists affected areas and collaborates with other international organizations.

National Planning
Countries are expected to meet the core national capacity requirements pertaining to radiation emergencies. The public health sector must be prepared to provide care to the affected individuals.

The World Health Organization (WHO) uses its Collaborating Centres and global expert networks Radiation Emergency Medical Preparedness and Assistance Network (REMPAN) and BioDoseNet to assist countries to strengthen their national capacities through developing technical guidance and tools, information dissemination, training, exercises, and support to the research and development.

International Collaboration
WHO works with other international organizations under the framework of the Inter-agency Committee for Radiological and Nuclear Emergencies (IACRNE) to provide policy advice and technical support for national health authorities on preparedness, response, recovery and long-term follow-up for populations affected by radiation emergencies.