(The Comparison of Methods of Discrere Payment Vehicle (Dichotomous Choice) in Improving the Quality of the Environment (a case study of air pollution in Tehran

Using methods to estimate the value of environmental goods seems to be essential for economic planning and moving towards development. In this paper, using methods of Discrere Payment Vehicle (dichotomous choice) i.e. single-bounded and double- bounded dichotomous choice, which are common method of contingent valuation, the value of air pollution in Tehran and households' willingness to pay to improve air quality, in four selected regions (Shahr-e-Ray, Shoosh, Haft-e-Tir and Tajrish) is estimated and the corresponding results of these two techniques were compared. The results showed that the total value of air quality improvement, calculated through two techniques of double-bounded and single-bounded dichotomous choice were respectively 2398657500 and 1492566000 thousands Rials in a year and weighted mean of each citizen's willingness to pay to improve air quality, calculated through these two methods, was estimated to be 282192 and 175596 Rials in a year respectively. Considering the annual damage to health, for any one percent increase in pollutants and yearly cost of pollution reduction which are respectively 1199000000 and 7336000000 thousands Rials, it was determined that citizens' willingness to pay through two methods, includes 20 and 30 percent of the cost of pollution control respectively, while 70 percent of pollution is due to mobile sources, and also citizens' willingness to pay involves a small percent of damage to the health of the citizens. However, citizens' low willingness to pay is attributed to citizens' distrust of government policies as well as their ignorance of the harmful effects of air pollution. In general, the results of this study, with regard to the cost of pollution from single-bounded dichotomous choice are closer to actual market conditions.

environmental economics, contingent valuation, techniques of single-bounded and double-bounded dichotomous choice.