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In recent years, the environmental Kuznets curve (EKC) hypothesis has become a major subject among issues dealing with environmental economics. This curve tries to show an inverse U-shaped relation between economic development indicators and pollution. In this study, the curve has regionally been considered in the city of Tehran with respect to its municipal solid wastes. The results confirm that over the period 1996 to 2006 there has been no sign of the EKC in Tehran. However, the source separation of dry wastes policy was effective in decreasing the slope of the so called EKC as it is expected.

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Regarding environmental importance and the lack of analytical methods for environmental policies, in this paper, shadow price for NOx and SOx emissions has been estimated for the Iranian electric industry. Input distance function is used for estimating shadow prices. The estimated shadow prices have revealed that the cost of Iranian electric industry for reducing one KG of NOx and Sox is 14991 and 17687 Rials, respectively. Estimated shadow prices in this study are greater than the amount offered by EPO (Environment Protection Organization) and World Bank. So it is recommended that any fine should be taken according to the emission shadow price.

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Shadow economy is an important part of economy in almost all countries especially the developing ones. Most of active firms in this part of economy have negative externality on the environment. Considering the importance of sustainable development and growing international pressures to maintain and support the environment more and more attentions have been drawn to the factors affecting and threatening environmental health. The present paper for the first time considers the role of variables like polity index and active population to total population ratio and how they affect the shadow economy. In addition to the main direct effects of these variables on shadow economy the indirect effects of causal variables through interaction with shadow economy are also examined. Since the relationship between shadow economy and air pollution has been somehow disregarded in economic literature to a large extent in Iran and to some extent at international level the present paper for the first time focuses on the relationship between shadow economy and air pollution. The results indicate that on average the ratio of shadow economy to GDP is 12.25% and a 1% increase in the size of the shadow economy raises the water pollution by 0.17%.

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Choice experiment as a subset of choice modeling approach is the newest method for calculating the value of non-market goods and estimating individuals’ preferences in dealing with environmental goods. This study evaluates the individual preferences for different characteristics of the historical - recreational Ganjnameh site of Hamadan based on Lancastrian value theory and stochastic utility function. It uses the choice experiment, the conditional Logit model with Weibull (Gumbel) distribution of disturbance terms and Housman- Mac Fadden method for testing Heteroskedasticity and equality of cross elasticities among options of a choice set. The welfare effects of proposed policies can be computed using estimated willingness-to-pay for different levels of characteristics of an environmental good. Sampling was performed randomly among native and non-native tourists in summer 2011. About 216 out of 300 questionnaires were correctly completed that led to the 1296 observations in 3888 data lines. Results indicate that people have relatively high willingness-to-pay for policies adopted to preserve and improve the quality of various characteristics of ecosystem goods. People have the highest willingness-to-pay for preserving the ancient monuments, environmental health, cleanness of river water and maintaining forest diversity and natural landscape, respectively. The socio-economic variables such as age, being married, parenting, education levels, monthly household expenditure and locality result in increasing WTP.