Cramer, James C. 1996/1997. "A Demographic Perspective on Air Quality: Conceptual Issues Surrounding Environmental Impacts of Population Growth." Human Ecology Review. 3.2:191-196.
A reasonable question that demographers often ask is, "What are the environmental impact of population growth?" This paper examines conceptual issues raised by asking this question about air quality in California. The conventional IPAT model must be modified in conventional ways noted by others: e.g., it must be made stochastic; the specification of population must incorporate congestion, dispersion, and age composition; and both direct and indirect effects of population must be examined. Other conceptual problems have received less attention. One problem is boundaries; pollution in a geographic area may be caused by populations elsewhere, so analysis should focus on emissions rather than pollution. A second problem is the need for disaggregated analysis, as population may be more strongly associated with some sources of emissions than with others. Finally, population may best be measured as the number of households, not the number of individuals.