Usually common sense and a preliminary review of available data by a competent professional will indicate which exposures to hazards are likely to be trivial and need be taken no further, and which ones will need a formal assessment of likely exposure. Young children ingest much more soil, earth, dust and paint than adults. In other words, after assessing exposures, the exposure-response relationship is the means of translating estimates of exposure into risks to health. It will need an input of the exposure estimates. Other data which may be needed includes information about the characteristics of the population likely to be exposed, and whether some are potentially more susceptible than the general population.
Babies are particularly susceptible to nitrates in drinking water.
Atopic asthmatics may be more sensitive to respiratory irritants. Health risk can be expressed as the frequency with which a given level of harm may be expected from hazards associated with a particular development. Amongst other things, we need to be clear about the nature and severity of the harm, the number of people at risk, and the period of time during which the specified number of new harmed cases will arise. By striving to prevent these we will most certainly control the risk of death from overexposure as well. Building a sewage processing plant could reduce the risk of gastrointestinal and other infective illness attributed to the sewage pollution that had hitherto affected a beach, even though it may have other undesirable consequences.