Balal Oroji
Abstract
Introduction: Implementing control plans, monitoring, and formulating traffic and management laws requires obtaining basic information about the origin of particles, physicochemical properties, and their behavior in the atmosphere. Gathering this information requires studying the various dimensions of ...
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Introduction: Implementing control plans, monitoring, and formulating traffic and management laws requires obtaining basic information about the origin of particles, physicochemical properties, and their behavior in the atmosphere. Gathering this information requires studying the various dimensions of the nature of particles, most of which will not be directly possible. The challenge of air pollution in the metropolis of Tehran requires fundamental studies, and in this study, we tried to present new dimensions of physicochemical and fundamental properties of atmospheric particles in Tehran. Material and methods: The particle collection process to evaluate their concentration and chemical composition was performed by a high-volume sampler for 1 to 24 hours and an average flow of 1.7 m3/min on fiberglass filters. Also, to determine the aerodynamic diameter distribution of the particles, a cascade sampler (Anderson impactor) with a flow of 28.3.3 L/min was used for 72 hours to 7 days. After sampling, the samples were prepared to determine the total concentration and aerodynamic distribution in the laboratory. Results and discussion: The results showed that the mean particle concentration during the sampling period was 118.6 ± 11.9 µg/m3. During the sampling period, the highest concentration of collected particles was 154.61 ± 22.1 and the lowest was 129/12 ± 23.15 µg/m3. The results of SEM analysis of the collected samples showed that the particles were present in a spherical, irregular, fibrous shape as well as crystalline shape. The predominant elements in these samples are K, Ca, Cl and Fe, which are found in combination with Ti, Zn. Cluster-like and amorphous structures rich in O, Zn, Mg, Fe, K, Si, and Na were observed in particles with dimensions of 2 to 7 micrometers. Conclusion: According to the results and comparison with other work done in this field, more particulate matter is emitted during fuel combustion processes by industry and urban transportation. Larger particles are also produced and emitted by vehicles, construction, and industry during human activities such as road dust.
Balal Oroji; Eisa Solgi; Asghar Sadighzadeh
Volume 15, Issue 4 , January 2018, , Pages 79-100
Abstract
Introduction:
Despite past improvements in air quality, very large parts of the population in urban areas breathe air that does not meet European standards let alone the health-based World Health Organisation Air Quality Guidelines. Over the last 10 years, there has been a substantial increase in findings ...
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Introduction:
Despite past improvements in air quality, very large parts of the population in urban areas breathe air that does not meet European standards let alone the health-based World Health Organisation Air Quality Guidelines. Over the last 10 years, there has been a substantial increase in findings that particulate matter (PM) air pollution is not only exerting a greater impact on established health endpoints, but is also associated with a broader number of disease outcomes.
Materials and methods:
Recently, relatively good research has been done on the understanding of the nature of particles and their role in creating a problem in humans. A comprehensive study of this research and the analysis of their results, along with the comparison of the results of the research on health impact assessment were evaluated in Tehran.
Results and discussion:
Data strongly suggest that effects have no threshold within the studied range of ambient concentrations, can occur at levels close to PM2.5 background concentrations and that they follow a mostly linear concentration-response function. Having firmly established this significant public health problem, there has been an enormous effort to identify what it is in ambient PM that affects health and to understand the underlying biological basis of toxicity by identifying mechanistic pathways-information that in tum will inform policy makers how best to legislate for cleaner air. Another intervention in moving towards a healthier environment depends upon the achieving the right public attitude and behavior by the use of optimal air pollution monitoring, forecasting and reporting that exploits increasingly sophisticated information systems.
Conclusion:
Improving air quality is a considerable but not an intractable challenge. Translating the correct scientific evidence into bold, realistic and effective policies undisputedly has the potential to reduce air pollution so that it no longer poses a damaging and costly toll on public health.
Balal Oroji; Hosain Bahrami; Mohammad Sadegh Oliaei
Volume 14, Issue 4 , January 2017, , Pages 75-90
Abstract
Introduction: Absorptive wells are one of the most common forms of onsite sanitation facilities in many developing countries. These latrines are suitable as a means of isolating human waste; however, conditions within pits often lead to nitrification of the contained waste. In areas with a near-surface ...
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Introduction: Absorptive wells are one of the most common forms of onsite sanitation facilities in many developing countries. These latrines are suitable as a means of isolating human waste; however, conditions within pits often lead to nitrification of the contained waste. In areas with a near-surface aquifer, the potential for nitrate pollution arising from Absorptive wells cannot be ignored.Material and methods: In this study, Hypothetical aquifer was made, to gather relevant information about the Absorptive wells in use and the soil and groundwater underneath the Hypothetical aquifer. Modeling was then conducted to demonstrate the potential for nitrate pollution of the groundwater from the latrines in such settings. The depth from the bottom of the pits to the water table was considered as 5, 10 or 30 m, to represent the range of aquifer depths at the study sites. Nitrate half-lives ranging from 500 to 1500 days were considered, and time scales from 6 months to several years were modeled.Results and discussion: The results highlighted the high likelihood of nitrate pollution of groundwater reaching levels exceeding the World Health Organization guideline value for nitrate in drinking water of 50 mg/L after as short a period as two years for the aquifer situated 5 m below the pits, when considering moderate to long nitrate half-lives in the subsurface. Careful siting of latrines away from high water table areas, more frequent pit emptying, or switching to urine diversion toilets may be effective solutions to reduce nitrate passage from Absorptive wells into groundwater, although these solutions may not always be applicable, because of social, technical and economic constraints.Conclusion: The study highlights the need for more reliable data on the typical nitrate concentrations in Absorptive wells and the nitrate half-life in different subsurface conditions.
