Searching for an Environmental Kuznets Curve in China's air pollution

Intuitively, the concept of an Environmental Kuznets Curve (EKC) is relatively easy to understand: pollution will initially increase with economic development but then decrease again as incomes attain a certain level. The overall concept of pollution, however, actually consists of various components which may behave differently and are not easily combined into a single measure. As a result, the measurement or tracking of an EKC becomes more difficult as one tries to develop a tractable measure of pollution for modeling or policy purposes. For example, in China levels of sulfur dioxide and particulate pollution show some signs of diminishing while nitrogen dioxide levels have increased as China's auto fleet has grown. Consequently, different studies estimating an EKC often generate different results depending upon which pollutant is used and how it is measured. This paper generates composite measures of Chinese air pollution using Nemerow methodology as well as a new epidemiological index based upon the health effects of the pollutants. The paper then tests these index measures to determine whether they display evidence of an EKC and also to examine how they behave in comparison to the individual pollutants.