2006

The economic value of preventing adverse health effects related to air pollution is estimated using contingent valuation in three diverse locations in China. Values are estimated for three health endpoints: cold, chronic bronchitis, and fatality. Alternative statistical models are tested to study their impact on estimated willingness to pay (WTP) and on the relationship between WTP and respondent characteristics. Using the official exchange rate, the sample-average median WTP to prevent an episode of cold ranges between US$3 and US$6, the WTP to prevent a statistical case of chronic bronchitis ranges between US$500 and US$1,000, and the value per statistical life ranges between US$4,000 and US$17,000. Estimated mean values are between two and thirteen times larger. Our estimates are between about 10 and 1,000 times smaller than estimates for the US and Taiwan using official exchange rates. Indoor air quality, measured for a subset of respondents, shows no consistent relationship with WTP.

In this study we use Divisia index approach to identify key factors affecting CO₂ emission changes of industrial sectors in Taiwan. The changes of CO₂ emission are decomposed into emission coefficient, energy intensity, industrial structure and economic growth. Furthermore, comparisons with USA, Japan, Germany, the Netherlands and South Korea are made to have a better understanding of emission tendency in these countries and to help formulate our CO₂ reduction strategies for responding to the international calls for CO₂ cuts. The results show that economic growth and high energy intensity were two key factors for the rapid increase of industrial CO₂ emission in Taiwan, while adjustment of industrial structure was the main component for the decrease. Although economic development is important, Taiwan must keep pace with the international trends for CO₂ reduction. Among the most important strategies are continuous efforts to improve energy intensity, fuel mix toward lower carbon, setting targets for industrial CO₂ cuts, and advancing green technology through technology transfer. Also, the clean development mechanism (CDM) is expected to play an important role in the future.

This analysis seeks to evaluate the influence of emission source location on population exposure in China to fine particles and sulfur dioxide. We use the concept of intake fraction, defined as the fraction of material or its precursor released from a source that is eventually inhaled or ingested by a population. We select 29 power-plant sites throughout China and estimate annual average intake fractions at each site, using identical source characteristics to isolate the influence of geographic location. In addition, we develop regression models to interpret the intake fraction values and allow for extrapolation to other sites. To model the concentration increase due to emissions from selected power plants, we used a detailed long-range atmospheric dispersion model, CALPUFF. Primary fine particles have the highest average intake fraction (1 × 10^− 5), followed by sulfur dioxide (5 × 10^− 6), sulfate from sulfur dioxide (4 × 10^− 6), and nitrate from nitrogen oxides (4 × 10^− 6). For all pollutants, the intake fractions span approximately an order of magnitude across sites. In the regression analysis, the independent variables are meteorological proxies (such as climate region and precipitation) and population at various distances from the source. We find that population terms can explain a substantial percentage of variability in the intake fraction for all pollutants (R² between 0.86 and 0.95 across pollutants), with a significant modifying influence of meteorological regime. Near-source population is more important for primary coarse particles while population at medium to long distance is more important for primary fine particles and secondary particles. A significant portion of intake fraction (especially for secondary particles and primary fine particles) occurs beyond 500 km of the source, emphasizing the need for detailed long-range dispersion modeling. These findings demonstrate that intake fractions for power plants in China can be estimated with reasonable precision and summarized using simple regression models. The results should be useful for informing future decisions about power-plant locations and controls.

Intake fractions, an emissions-intake relationship for primary pollutants, are defined and are estimated in order to make simple estimates of health damages from air pollution. The sulfur dioxide (SO₂) and total suspended particles (TSP) intake fractions for five cities of China are estimated for the four main polluting industries—electric power generation, mineral (mostly cement) products industry, chemical process industry and metallurgical industry (mainly iron and steel smelting). The Industrial Source Complex Long Term (ISTLT3) model is used to simulate the spatial distribution of incremental ambient concentrations due to emissions from a large sample of site-specific sources. Detailed population distribution information is used for each city. The average intake fractions within 50 km of these sources are 4.4 × 10^- 6 for TSP, and 4.2 × 10^- 6 for SO₂, with standard deviations of 8.15 × 10^- 6 and 9.16 × 10^- 6, respectively. They vary over a wide range, from 10^- 7 to 10^- 5. Although the electric power generation has been the focus of much of the air pollution research in China, our results show that it has the lowest average intake fraction for a local range among the four industries, which highlights the importance of pollutant emissions from other industrial sources. Sensitivity analyses show how the intake fractions are affected by the source and pollutant characteristics, the most important parameter being the size of the domain. However, the intake fraction estimates are robust enough to be useful for evaluating the local impacts on human health of primary SO₂ and TSP emissions. An application of intake fractions is given to demonstrate how this approach provides a rapid population risk estimate if the dose-response function is linear without threshold, and hence can help in prioritizing pollution control efforts.