This can be considered an "objective" and "quantitative" study, because of the degree of control on exposure and interpretation of the effects of exposure. The ability to eliminate other environmental factors is important because the presence of other substances may cause synergistic or mitigating effects with the effect of the toxin under study.

The inability to adequately test for long-term exposure is a serious shortcoming, because typical exposures to urban smog, for example, are for long periods of time at low concentrations.

Another disadvantage is that most toxicological studies involve exposing animals, not humans, to the pollutants. The results may not be exactly applicable to humans.