ABSTRACT
An organism can respond to pollutant exposure in as many ways as its total number of properties and functions. Thus, if one can define and measure a property or function, it can be used as a biological endpoint in an inhalation study. Furthermore, no matter what is selected for measurement, there will be number of airborne materials that, in sufficient concentration and exposure time, will produce a statistically significant change in the endpoint. But until the role of the measured property is understood in terms of its relationship to harm or disease, one does not know how to treat the result. In other words, it may be a health effect or just basic scientific information.
