Estimating health damage cost from secondary sulfate particles--a case study of Hunan Province, China

China's coal-dominated energy pattern has resulted in large amount of SO2 emissions. Estimate of the sulfur-related health damage cost is necessary to help perform systematic cost-benefit analysis and set national energy and emissions control priorities. Current researches were confined to gaseous SO2 in urban areas; however, secondary sulfate (SO4(2-)) particles can exert serious impact in a wider region. Based on the concept of "intake fraction", CALPUFF long-range dispersion model and 180 sample emission sources, multiple regression equation was obtained with good correlation( r = 0.85), which illustrates that populations were key parameters to determine intake fraction but source characteristics were insignificant. Based on the formula and the population distribution data, county-level intake fractions were mapped for Hunan Province(range: 1.1 x 10(-6) - 3.2 x 10(-6)) of China. A combination of county-level SO2 emissions with the intake fractions yields a total 1.98 tons of sulfate(SO4(2-)) inhalation, and resulting total health damage cost to be 0.76(willingness to pay approach, WTP) or 0.16 (human capital approach, HC) billion USD in 1997, about 2.1% or 0.45% of GDP in Hunan in 1997. Average health damage cost per ton of SO2 emission is 930(WTP) or 200 USD(HC). The results demonstrated that more stringent regulation should be forced.