The ability to detect the odor and taste of chlorine dioxide is related to its concentration. At the concentrations allowed by the EPA, no one suffers adverse effects, the odor is just barely noticeable, and there is no taste.
In industrial settings healthy people who are exposed to high concentrations of chlorine dioxide experience nausea, vomiting, and diarrhea. It is not hard to imagine that the healthier you are, higher concentration are needed to experience adverse effects, although I don't think this has been tested or proven.