Introduction: Estimating air pollution levels in areas with no measurements is a major concern in health-related studies. Therefore, the aim of this study was to investigate the amount of exposure to particulate matter below 2.5 μ (PM2.5) in the metropolis of Tehran.
Materials and methods: The hourly concentrations of PM2.5 during 2017-2018 period were acquired from the Department of Environment (DOE) and Air Quality Control Company of Tehran (AQCC). The hourly concentrations were validated and 24-h concentrations were calculated. Inverse distance weighting (IDW), Universal Kriging, and Ordinary Kriging were used to spatially model the PM2.5 over Tehran metropolis area. Root Mean Square Error (RMSE) and Mean Error (ME) were used to measure and control for the accuracy of the methods.
Results: The results of this study showed that RMSE and MENA values in Kriging method was less than the IDW, which indicates that the Kriging was the best method to estimate PM2.5 concentrations. According to the final map, the highest annual concentrations of PM2.5 were observed in the southern and southwestern areas of Tehran (districts 10, 15, 16, 17, and 18). The lowest exposure to PM2.5 was found to be in districts 1, 2, 3, 6, and 8.
Conclusion: It can be concluded that Kriging method can predict spatial variations of PM2.5 more accurately than IDW method.

Introduction: Estimating air pollution levels in areas with no measurements is a major concern in health-related studies. Therefore, the aim of this study was to investigate the amount of exposure to particulate matter below 2.5 µ (PM2.5) in the metropolis of Tehran.
Materials and methods: The hourly concentrations of PM2.5 during 2017- 2018 period were acquired from the Department of Environment (DOE) and Air Quality Control Company of Tehran (AQCC). The hourly concentrations were validated and 24-h concentrations were calculated. Inverse distance weighting (IDW), Universal Kriging, and Ordinary Kriging were used to spatially model the PM2.5 over Tehran metropolis area. Root Mean Square Error (RMSE) and Mean Error (ME) were used to measure and control for the accuracy of the methods.
Results: The results of this study showed that RMSE and MENA values in Kriging method was less than the IDW, which indicates that the Kriging was the best method to estimate PM2.5 concentrations. According to the final map, the highest annual concentrations of PM2.5 were observed in the southern and southwestern areas of Tehran (districts 10, 15, 16, 17, and 18). The lowest exposure to PM2.5 was found to be in districts 1, 2, 3, 6, and 8.
Conclusion: It can be concluded that Kriging method can predict spatial variations of PM2.5 more accurately than IDW method.

Introduction: The purpose of this study was to investigate and compare the effect of iron oxide nanoparticles on the adsorption of sulfur dioxide by modified zeolite with hydrochloric acid. In this investigation was used modified zeolite with HCl with and without iron oxide nanoparticles (Iron Oxide Nanoparticles@Clinoptilolite/HCl) as adsorbent.
Materials and methods: Structural characteristics, chemical composition and specific surface area of adsorbent were determined using the FTIR, FESEM, EDX, Mapping, XRD, XRF and BET techniques. Glass cylinder filled with zeolite seeds and SO2 cylinder balanced with N2 gas was used for experiments. It was evaluated factors affecting SO2 uptake process including temperature and contact time, also thermodynamics and kinetics of adsorption. Sulfur dioxide adsorption of real sample was taken with both adsorbents.
Results: Adsorption efficiency of SO2 in the synthetic and actual sample were %82.8±5.5 and %67.2±7.21 respectively, by modified zeolite with HCl and iron oxide nanoparticles in the optimum conditions of temperature of 25 °C and duration 28.5 min. As well as, removal percentage average was obtained in the synthetic and actual sample %46.1±4.34 and %35.8±5.85 respectively, by modified zeolite with HCl without nanoparticles in optimum condition of temperature of 25 °C and contact time of 20.5 min.The results showed that SO2 adsorption is an exothermic and spontaneous process and adsorption kinetics of sulfur dioxide by both adsorbent is more consistent Pseudo-second order kinetics model.
Conclusion: The use of iron oxide nanoparticles on the zeolite can increase SO2 removal efficiency from the gas phase.

Introduction: Dust created by mining activities is one of the most important concerns regarding human health and the environment protection. This is due to the fact that dust particles have a high potential to carry heavy metals or they can produce a dangerous contaminant when combined with a special mineralogy or morphology. The aim of this study was to identify the mineralogical and morphological characteristics of dust particles found around the lead and zinc mine of Mehdiabad.
Materials and methods: First of all, dust samples were collected around the mine by installing 8 passive marble dust collectors using a combined systematic random method during February, March and April in 2020. Then, using two methods of X-ray diffraction (XRD) and scanning electron microscopy (SEM) mineralogy, shape and distribution of the particles of dust samples were investigated.
Results: The highest frequency of particles with sizes less than 10, 10-60, and 60-100 microns were determined and observed in S1 station in the northwest, and S5 and S2 stations in the southwest of the mine, respectively. The results of SEM analysis revealed that the appearance of dust particles is mostly spherical, irregular, elongated, prismatic, and rhombic. The results of XRD analysis showed that the minerals anorthite (Ca (Al₂Si₂O₈)), dolomite (Ca Mg (CO₃)₂), albite (NaAlSi₃O₈), calcite (CaCO₃), quartz (SiO₂) and muscovite (KAl₂ (Si₃AlO₁₀)) (OH₂) have the highest frequency in dust samples.
Conclusion: The findings show that the predominant mineralogical composition of dust particles includes carbonates (dominant mineral: calcite) and silicates (dominant mineral: quartz) which are found in all stations. Thus, dust particles, with high frequency of quartz, have a high potential to result in respiratory diseases in the inhabitants living around the mine.

Introduction: Industrial safety and a healthy environment reduce the illnesses, injuries, and accidental incidents of the workers as well as property damages. The study aimed to identify the health risk issues and assess their impacts on labors around the brick kiln areas in Bangladesh.
Materials and methods: The study conducted a survey based on a structured questionnaire to collect health-related compliance from the brick kiln workers. It also selected 12 brick kiln clusters in Rajshahi and Gazipur districts, and several samplings were made. The analyzed data were compared with the prescribed national and international standards.
Results: The survey results showed that the respondents were suffering from different diseases like respiratory and skin diseases, eye irritation, fatigue, hearing problem, headache, etc., due to the occupational hazard in the kiln areas. The study results illustrated that the particulate matter pollutants, including PM2.5, PM10, and SPM were found higher than the permissible standard that caused asthmatic disease. Most of the physicochemical parameters for surface water analysis exceeded the permissible standard indicating water pollution occurred around the kiln areas. The sound level was found higher than the acceptable level of Department of Environment, Bangladesh (DoE) standard 75 dB.
Conclusion: The study observed that brick kiln emitted gases caused huge pollution in the areas threatened the human health and the crusher machine created the high intensity of noise resulted in significant adverse health impacts of the brick kiln labor. However, most of the labors were not well aware of occupational safety and hazards, and health-related compliances in the kiln areas.

Clean and healthy air is the joy of human life that needs it more than food and water. Today's modern industry produces a lot of gases and particles that pollute the open air. Air pollution, as one of the concerns of the present age, in addition to environmental degradation and economic damage, poses serious risks to human health. Continuous monitoring of air quality to identify pollutants and identify sources of their emissions is also one of the basic strategies for controlling air pollution. Adverse air quality causes a lot of damage to humans and the environment and various health effects. Air pollution is a major environmental threat to human health in many developed or developing cities around the world. The level of air pollution is usually determined by the concentration of air pollutants such as dioxide hydrogen, sulfur dioxide, carbon monoxide, ozone and suspended particles. In recent years, air quality has been a major factor in the emergence of quality of life in urban areas, especially in densely populated and industrial areas. Air pollution with a wide range of suspended particles has effects on human health, including the respiratory and cardiovascular systems, as well as mortality. In this article, the effects of air pollution on the environment and sources and the source of pollution in Ahvaz city are introduced.