فصلنامه محیط شناسی
سال چهل و هشتم شماره 4 (پیاپی 104، زمستان 1401)

Today, air pollution has become one of the most critical problems in densely populated cities, which causes many city residents to suffer from lung problems every year and can have irreparable effects on citizens' health. Air pollution recording devices in cities record pollution hourly. The technical issues of these devices sometimes cause some of the important data not to be recorded, and as a result, fixed values ​​are created in the data. In this study, fixed values ​​have been estimated. For this purpose, the study of air pollution events in Tehran including the concentration of PM2.5, PM10, SO2, NO2, O3 and CO pollutants was conducted. The LANN algorithm, used in the estimation and forecasting of single-variable time series, has been implemented and compared for all pollutants. Also, in another part of the study, other environmental pollutants have been considered in the estimation of fixed values, and by using the neural network method, the estimation of fixed values ​​for all pollutants has been done. RMSE index was also used to check and compare algorithms. The value of RMSE in the LANN method was lower than other simpler models including mean, linear regression and LOCF, so its value was 30 to 50% lower, depending on the type of pollutant. Also, the neural network algorithm had lower RMSE than other methods in estimating PM2.5 values ​​and its value was 7.78.

Small wind turbines are developed to help harvest clean wind energy within the built environment and to avoid energy losses and negative environmental effects associated with wind farms. A common issue is that the wind speed in the urban environment, especially at low altitude, does not necessarily meet the minimum speed required by the microturbines. Since the production power of the turbines has a direct relationship with the speed of the wind, it is necessary to place the turbine in a place with maximum wind speed. The purpose of this article is to identify the optimal location of the microturbine between and on the roof of buildings, so that by using the maximum available wind speed, the microturbine can show optimal performance. By comparing the wind speed at various points in 6-, 12- and 18-meters wide corridors between buildings in Qazvin City with relatively good wind potential, as well as three points on the middle axis of the rooftop, CFD simulation and 3D profiles show that it is possible to locate areas in corridors between low-rise buildings where the wind speed gets accelerated by up to 43%, which creates an opportunity for on-site use of renewable wind energy.

The issue of optimal disposal of sludge in water treatment plants is among the important issues in line with the principles and goals of sustainable development. In this study, the possibility of applying activated carbon and water treatment sludge with the purpose of reducing the consumption of cationic polyelectrolytes in the thickening stage of wastewater treatment sludge on a laboratory pilot scale was investigated. For this purpose, the effect of these additives on SVI, TTF, DS, pH, and the dosage of polyelectrolytes used was evaluated. SVI and TTF of conditioned sludge at a dose of 300 mg/g along with 1 mg/l of cationic polyelectrolyte decreased to less than 100 ml/g and 100 s-1, respectively, and also increased the amount of sewage sludge solids to at least 5%. Large flocs formation, particles size distribution change, and increasing the porosity of the sludge have become as a result of adding the conditioning materials, and facilitating the thickening and releasing of free water. In addition to improving the efficiency of sewage sludge thickening, these industrial wastes reduce polyelectrolyte consumption by 50%, protecting the environment from the negative impacts of their disposal.

People in the society directly and indirectly contribute to air pollution. Therefore, besides being an organizational and governmental responsibility, the participation of individuals in this matter can be significant in air pollution control. Using the developed theory of planning behavior, this study analyzed the behavior of households to decrease air pollution in Kerman City by investigating pollution, vehicles, electricity consumption, green spaces and reused and recycled appliances. The method of this research was quantitative in terms of the nature of data and practical in terms of purpose. The statistical population was all the households living in Kerman City, due to the lack of access to all the households in this research, 384 households were selected from the available sample. The data analysis tool used in this research was structural equations. The results showed that the variable of perceived behavioral control is the main driver of the intention of households to reduce air pollution, followed by the variables of attitude, mental norm, and past behavior had a direct effect on the individual intention of households to reduce air pollution. In order to reduce pollution and increase the health of households and reduce pollutants in this city, it is suggested to use fewer private vehicles and use public vehicles, plant trees and increase green spaces, and cooperate with the government to reduce the production of greenhouse gases.

Biodiversity is an important structural feature of dynamic and complex forest ecosystems. One of the most challenging and important issues in assessing the structure of forest ecosystems is understanding the relationship between biodiversity and environmental factors. Hyrcanian Forests are considered a biodiversity hotspot in the world and have special and unique features that have led to an emphasis and importance of biodiversity conservation in these forests. The aim of this study was to investigate the effect of biotic and abiotic factors on the diversity and richness of tree species in Hyrcanian Forests from the west of Gilan province to the east of Golestan province. For this purpose, using 655 fixed sample plots (0.1 hectare), the diversity of trees in 3 provinces in the northern Iran from east to west of the Caspian Sea was analyzed. A combination of non-parametric models including random forest (RF) and support vector machine (SVM) and linear regression models were used to investigate the relationship between tree diversity and biotic and abiotic factors. Biotic and abiotic variables included the number of trees per hectare, diameter, respectively. Basal area (BA), Basal Area in Largest tree (BAL), slope, aspect and elevation. Evaluation statistics including the coefficient of determination, RMSE and percentage RMSE error showed that the random forest model was the best model to determine the relationship between biodiversity and environmental factors and has suitable accuracy for determining biodiversity changes in the northern forests of Iran.

Creating high-quality living spaces is a prerequisite for any living complex. This research aims to investigate the relationship between the quality of urban space and land segregation patterns in Ardabil City. The current research type is applied in terms of purpose and descriptive-analytical in terms of nature and is based on structural equation modeling. The data were collected through a questionnaire based on 6 indicators (access, spatial and physical, transportation, mental comfort, security, enjoyment of the neighborhood) and 35 items. The responses were collected from the residents of Malabashi neighborhood and Sablan settlement phase 2 in Ardabil City and with a sample size of 240 people. The collected data were analyzed using SPSS and Smart-PLS software. According to the results, the quality of the urban space of Malabashi neighborhood was in a very unfavorable condition from the residents' point of view, and the level of satisfaction of the citizens with the accessibility, transportation, physical-spatial condition of the city was very low. Also, based on the findings of the research in the neighborhoods of Sablan Phase 2 as a checkered pattern, since the pattern of the expansion of this settlement was premeditated in terms of physical-spatial, access, transportation and all the facilities that are necessary for living in a settlement, the state of this neighborhood was considered satisfactory by the respondents. Also, based on the results of the Pearson test, there is a positive and significant correlation between the variable of land segregation patterns and the quality of urban space. As a result, because the checkered pattern is prepared and planned in advanced, it can be one of the suggested patterns for urban expansion. In this regard, based on the results of the research, by combining the relationship between patterns of land separation and the quality of urban space, as well as with the spatial justice of the city and the correct separation of land in Ardabil City, it is possible to improve the vitality and quality of the city's neighborhoods.

Identification of homogeneous units is one of the important steps in land planning and management. Therefore, this study aims to characterize the homogeneous landscape units (HLUs) that form the basis of landscape assessment and aesthetics studies. At first, by literature review, some criteria and indicators have been chosen to identify the homogeneous unit. Then, on this basis and according to the study's scale and the study area's conditions, the indicators used to characterize the homogeneous unit and mapping with the aim of landscape assessment were selected. Then, maps of each of them were made, and by overlaying these maps, a HLU map was created. Finally, the HLUs were ranked based on three criteria i.e., distance to the road network, distance to rural settlements, and distance from inaccessible areas. We used the Shannon entropy-Vikor method for alternatives' priority. Homogeneous unit Characterization indicators included elevation, slope, vegetation landscape, village visibility, permanent and seasonal rivers visibility, landform and soil type, and vegetation type and density. The spatial integration of the indicators' maps led to the characterization of 913 HLUs in the form of 147 different compositions (homogeneous landscape units). The results showed that 18% of the study area is suitable for aesthetic assessment for tourism. The ranking with the Shannon entropy -Vikor method showed that about 10 percent of the characterized homogeneous units have the highest priority for aesthetic assessment with the purpose of tourism. The results of this study showed that by using spatial indicators related to landscape assessment, it is possible to identify an independent assessment unit for landscape assessments in geospatial land planning, especially for nature-based tourism purposes.

The temporal and spatial distribution pattern of providing ecosystem services is one of the basic characteristics of ecosystems. One of the important ecosystem services in many ecosystems, including watersheds in northern Iran, is soil maintenance. This valuable service has not been investigated in many areas, including the watersheds of developing countries. The present study was conducted with the aim of investigating the spatial-temporal changes of soil erosion and maintenance in the years 2000 and 2020. Also, in this research, two watersheds of Lahijan-Chabaksar and Astana-Kuchsefhan, in Gilan province, have been selected as the study area. From an ecological point of view, these watersheds are a symbol of the human and natural interwoven ecosystem, which has a high capacity in providing all kinds of ecosystem services and has undergone changes in recent years. The results show that the total amount of soil erosion potential in the studied area in the studied years is equal to 73755909 and 119218604 tons, respectively, and the amount of soil maintenance ecosystem service in these years in the entire watershed is 1222434092 and 1218191672, respectively. It is a body. Also, based on the results obtained, a small part of the region has the most soil and sediment losses. Therefore, the results emphasize the urgent need for targeted soil and water conservation measures to ensure the sustainability of the basin's resources.