This paper uses a new panel data set on state-level sulfur dioxide and nitr
ogen oxide emissions from 1929-1994 to test the appropriateness of the 'one
size fits all' reduced-form regression approach commonly used in the envir
onmental Kuznets curve literature. Empirical results provide initial eviden
ce that an inverted-U shape characterizes the relationship between per capi
ta emissions and per capita incomes at the state level. Parameter estimates
suggest, however, that previous studies, which restrict cross-sections to
undergo identical experiences over time, may be presenting statistically bi
ased results. (C) 1999 Elsevier Science B.V. All rights reserved.