1. All portals of entry from the environment into the body is estimated by the internal dose (so estimates from ambient concentrations of amounts inhaled, ingested or absorbed through the skin is effected by many factors, temp, site of the skin absorption rate.. ) while markers account for all these routes.

2. Ambient exposure typically fluctuate over time. So short-term fluctuation in dose measures at a single time will increase inter individual variability, markers that integrate dose overtime will reduce such variability and thereby reducing exposure misclassification. Or serial sampling could also reduce the variability.

3. Biomarkers sometime allow a series of dose estimates for different time points, eg hair.. it will give a wider time window of exposure.

4. Are useful for short term prospective studies or cross-sectional studies to study the recent precipitating factors of an illness, example an asthma attack, or a myocardial infarction.

5. Nonspecific markers for more than one chemical can also be useful, so in case of certain chromosomal abnormality, this will give an indication of total genetic damage from several different exposures, eg hazards from a certain job that involves several industrial processes.

6. Innovative specimens like biopsies and surgical specimens.

7. It combines the accuracy of laboratory experiments with real populations rather than animals and than the problems of extrapolation and dose calculation