Public Health Ambient Air Pollution in Shanghai: A Health-Based Assessment–HAIDONG KAN, BINGHENG CHEN, and CHANGHONG CHEN | Urbanization, Energy, and Air Pollution in China: The Challenges Ahead: Pro

effects linked to exposures to ambient air pollution, although recent studies in the United States have suggested an association (e.g., Pope et al., 2002).

Because some of the exposure-response functions we used in this analysis were not available in Chinese studies, we relied on international studies, conducted mostly in the United States and Western Europe. This raises the question of whether results from a developed country can be transferred to a developing country. For example, Chinese studies generally report lower coefficients for exposure-response relationships between air pollution and adverse health effects than studies in the United States and Europe. This is probably because of differences in levels of air pollution, local population sensitivity, age distribution, and especially air pollutant components. For instance, the composition of the motor vehicle fleet in Western Europe and the United States, where most of the epidemiological studies were performed, and the motor vehicle fleet in China differs substantially. Another major difference is the widespread use of coal in China, which suggests that the air pollution mix also differs substantially.

Ideally, when exposure-response functions from developed countries are applied to other regions, for example, Shanghai, they should be revised to account for local conditions, such as the physical (diameter, etc.) and chemical (components) properties of particulates, the socioeconomic status of local populations, etc. However, no reference data are available for such revisions. Until locally derived exposure-response functions become available, this will probably be the weakest part of an analysis.

Because no valuation study of the health end points associated with air pollution in Shanghai had been done before, we had to estimate values from previous studies of similar changes, a procedure called “benefit transfer” or “value transfer” in economics. Characteristics of the concerned population (e.g., age distribution, income, health status, culture) may have contextual effects on the valuation results. For example, different social and health-insurance systems greatly influence people’s risk perception, which affects the WTP to avoid the risk.

If we had transferred the U.S. VOSL directly to the Shanghai study, after accounting for the income difference between the two sites, the VOSL would have been US$780,000, which is much higher than the VOSL estimated in the Chongqing study. The number would be even higher if we had used purchasing power parity (PPP) as the income definition. Obviously, the estimate used in the Chongqing study is better fitted to the Shanghai study in terms of the economic and social situation. Therefore, we tried to use Chinese studies wherever they were available and attempted to stay on the conservative side with a range of reasonable estimates.

There are also inherent uncertainties in transferring values from other study sites, whether in China or elsewhere. Therefore, we strongly suggest that a WTP study for the avoidance of air-pollution-related health risks in Shanghai be undertaken, especially on the WTP to reduce the risk of premature death from air