Environmental Emissions and Production Economics : Implications of the Materials Balance

In modeling emissions, the literature has usually specified an explicit emission function, or treated emissions as a production input. We examine the validity of these approaches, taking into account the materials balance principle. We show that a technology can equivalently be described by (i) a production function with material and nonmaterial inputs and bounded marginal product of the material input, (ii) a well-behaved production function with emissions as an input, and (iii) a well-behaved emission function, if the materials balance is accounted for as an additional condition. We offer a forma derivation of common, but not rigorously established modeling approaches