For somewhat different objectives, human exposure assessment (HEA) is covered more fully and more frequently in epidemiology textbooks. Despite such coverage, there are still several reasons why some epidemiologists may find HEA also not appealing.

First, the efforts by many epidemiologists to associate human exposures to outcomes are primarily for etiology testing, not for health risk assessment. Second, as to be explained later, HEA is performed primarily for those chemical, physical, or biological contaminants present in the environment. Non-environmental or non-occupational epidemiologists often face different issues or agenda when assessing human exposure to intrinsic factors or agents that are not categorized as environmental contaminants. Third, as mentioned in the last slide, health risk assessment as a discipline is still in its infancy.

Epidemiologists who are less concerned with HEA per se are those dealing with either very concrete exposure levels, or exposures that are extremely intangible. When conducting a clinical trial, for example, most clinical epidemiologists already have a pretty good handle on the dose or treatment level at which the patients are being exposed. And for pyschosocial epidemiologists or the kind, they tend to work with personal trait, lifestyle, socioeconomic status, or the like as the risk factors. These factors tend to be quite intangible or less quantifiable, and their measurements hence often rely on the use of more tangible but less related factors as surrogate (e.g., through work histories, observed behaviors, surveys, etc.).