Application of intake fraction to population exposure estimates in Hunan Province of China

This article developed a new method, based on the concept of "intake fraction", to assess population exposure to primary and secondary fine particle matters from site-specific sources. This method was illustrated by a set of 17 power plants (totally 24 stacks) in Hunan Province of China. The CALPUFF long-range atmospheric dispersion model was used to simulate ambient concentrations of fine particles, and the GIS technology was used to generate a population distribution database from county-level population statistical data. An integrated computer program package was developed to carry out numerical integration of dispersion results over the population data, and produce intake fractions. The resulting average intake fractions within 500km were 9.73 x 10(-6), 2.39 x 10(-6), and 2.47 x 10(-6) for primary fine particles, sulfate and nitrate respectively. Regression analyses were performed to explore the relationships between intake fractions and potential variables. Results showed that the stack height and aggregate populations could be used to predict intake fractions of fine particles. R 2 of the regression equations were 0.83, 0.64, and 0.74 for primary fine particles, sulfate and nitrate respectively. Iso-intake fractions presenting geographical distributions of intake fractions in Hunan Province were mapped, showing a factor of about 2 between the highest values in the northeast and the lowest in the southwest of Hunan Province.