Results of pulmonary function tests (as an indicator of respiratory health) are from 11 to 13 percent lower in African Americans and other racial ethnic populations than in Caucasians when controlled for gender, age, and height. Environmental factors influencing these indices are circadian variation, altitude, air pollutants, technology, state of nutrition, smoking history, and other indicators of lifestyle. A combination of subtle, genetically determined anthropometric variants may also be operative, the extent of which is controversial. Population-based, population-specific standards are required to avoid erroneous diagnosis of cardiorespiratory disease, erroneous assessment of operative risk, unfair hiring practices when lung function tests are used for preemployment evaluation in dusty occupations, and unfair labeling when workers apply for disability compensation. Tailoring of statistical prediction standards from simple linear to more complex polynomial regression models will increase the accuracy of population prediction standards for pulmonary function variables into the 21st century.