Environmental hazards - Agents can endanger health (hazards) include the following:
- Biological - infectious agents, mould, pollen, biological warfare agents
- Chemical- natural or man-made (industrial, domestic, chemical warfare agents)
- Radiation - ionising ( e.g. nuclear) and non-ionising ( e.g.UV) emissions from natural sources e.g. radon or man-made e.g. deliberate release
- Physical - natural particulates and man-made pollution, volcanoes, forest fire combustion products, hydrocarbons, extreme weather events floods.
We get exposed to hazards in a variety of ways:
- Person to person (respiratory, skin to skin, sexual, faeco-oral or via devices)
- Animal (including vectors)
Limiting impact on health when such exposures have already occurred is vital when a public health incident occurs. This may come about in the following situations:
- single case of a serious illness with major public health implications ( e.g. botulism, viral haemorrhagic fever, vCJD, XDR- TB) where action is necessary to investigate and prevent ongoing exposure to the hazardous agent
- two or more linked cases of unexplained illness that could indicate the possibility that they may both be caused by the same known or unknown agent or exposure i.e. an outbreak;
- higher than expected number of apparently unlinked cases or geographic clustering of a serious pathogen
- high likelihood of a population being exposed to a hazard ( e.g. a chemical or infectious agent) at levels sufficient to cause illness, even though no cases have yet occurred ( e.g. contamination of the drinking water supply).