Airborne particulate matter with a diameter of 2.5 microns or less (PM2.5), as well as slightly bigger particles (PM10), arrive from the westerly direction and collect in the city centre of Tehran, the capital of Iran. The statistical characteristics and daily trend of the air quality index (AQI) in Theran were studied over an 11-year period (2002- 2012). Various statistical analyses were applied including descriptive statistics, correlation analysis, trend analysis and the sequential nonparametric Mann-Kendall test. The significance of the series was investigated by regression analysis and Kriging interpolation. It was found that Tehran's daily AQI increased by 11.8% over the study period, with the frequency distribution of days with good and average air quality showing a strongly declining trend. The AQI of Tehran was shown to contain a large part of PM10 and PM2.5, the latter having the largest contribution (coefficient=0.853).

Medical tourism refers to an international phenomenon of an individual's travel in which most tourists travel long to access to treatment-therapeutic services who because of high cost, long waits, lacking in insurance, and use of services and lack of access to health services in the destination.

The Persian Qanats, ancient underground aqueduct systems that have provided irrigation water to arid regions in Iran for over 3000 years, are recognized as a vital element of the country’s cultural heritage. Eleven of these impressive structures have been included on the UNESCO World Heritage List, underlining their cultural, social, political, and physical significance. As these underground heritage sites offer a unique opportunity for fostering territorial collaboration and social capital between tourists and the local community, it is important to develop a comprehensive model to influence the behavior of tourists, officials, and natives in their treatment of these invaluable sites. This study aimed to design a sustainable behavior model for underground heritage tourism management in Persian Qanats that have been listed as UNESCO World Heritage properties. The research employed a theme analysis approach, utilizing a statistical sample of 22 base managers and Qanat tourism experts. The study used content and thematic analysis to develop a research model that guarantees the sustainable protection of these valuable underground heritage sites by shaping the behavior of tourists, officials, and natives. The proposed model serves as a guideline for effective behavior management, leading to the preservation of these significant underground heritage sites for future generations. In conclusion, this study provides valuable insights into the sustainable management of Persian Qanats and the promotion of a strong sense of territorial collaboration and social capital between tourists and the local community.

Nowadays, social vitality is one of the most important needs of human communities, as citizens particularly those living in megacities have less opportunity to think about themselves and their needs, and may suffer from depression. As happiness is influenced by numerous structures of urban community, it also can influence development process as well as excellence of citizens and urban society; thus, this subject has been studied more from a psychological and sociological point of view. Accordingly, all the indicators influencing happiness in city should be considered in planning to have a happy city. Therefore, the present study was conducted to investigate and identify criteria and sub-criteria of a happy city, as well as determining importance of these variables.In this study, the research method is mixed in terms of data type; fundamental in terms of purpose, and descriptive-analytical in terms of the method of research. Qualitative data were collected using the documentary method and open questionnaire (first round of the Delphi method) and text analysis. Quantitative data were collected using the cross-sectional survey method with experts' questionnaires (the Delphi technique in three rounds). Sample size included 30 Iranian academic authors; that were selected using purposive sampling method. Results showed that, among 5 dimensions of happy city planning, economic, managerial-administrative are substantial, respectively. Among indicators, welfare and health were identified as the most significant indicators. Efficient management, social justice, mental-moral health, citizenship rights, income level, quality of life, urban security rate, and having a proper job were considered as the most important variables.

Many scholars of urban studies believe that the most important factor effective on the amount of individuals' welfare is housing.  Population increase of Iran and the expansion of the range of cities in Iran in recent decades cause centralization and increase in population densities in Iran and it seems that during recent years, economic policies of housing, as the interface ring for spatial planning policies of lands and urban and rural development, has been to some extent neglected by Iran's planning officials. Considering the multidimensionality of the issue of housing, for urban housing planning the intervention of different state and urban organizations is required and the lack of a comprehensive and integrated management is tangible in this issue. Regarding the domination of municipalities over internal issues of cities and also regarding geographical, political, economic and social conditions of different cities, municipalities can burden the responsibility of this issue. The objective of the present study is to investigate the problem of housing in Iran and providing an appropriate strategy for resolving this issue. Accordingly, the study, by doing library research, administering interviews and consulting state authorities and elites of housing markets and also by using the authors' scientific and executive experiences, an organizational structure was suggested for solving the housing issue. Then, by preparing questionnaires and surveying three groups (citizens, state and municipality authorities and academic specialists) this structure was evaluated using matrix QSPM and the SWOT model. Finally, by using the conducted surveys, the desired strategies were presented for improving the performance of organizational structure.