جستجوی مقالات مرتبط با کلیدواژه « ذرات معلق » در نشریات گروه « محیط زیست »

The growth of technology and industry has brought prosperity to mankind on the one hand, but on the other hand, it has caused the creation of physical, chemical, and biological pollutants in the environment and by creating unfavorable conditions in the work environment, it has endangered the basis of a healthy life. Suspended particles (Particulate Matter (PM)), sulfur oxides (SOx), nitrogen oxides (NOx), and carbon monoxide (CO) are among the standard and important pollutants in air pollution. In this research, the pollutants emitted from the chimneys of Semnan gypsum industries including carbon monoxide, sulfur dioxide, nitrogen oxides, particulate matter (PM10), and dry dust have been studied in five Semnan gypsum factories.

The concentration of PM10 and dry dusts was determined using a particle measuring device (TCR-Tecora) and a Testo 350-M/XL device was used to measure gaseous pollutants. Sampling of industrial chimneys as well as the space around the factories has been done in four places. Also, risk assessment has been done by the William-Fine technique, which is a systematic risk assessment method to identify possible risks, estimate the level of risk in risk management, and reduce it to an acceptable level.

In this study, the amount of NOx is between 24.5 and 39 ppm, the concentration of SO2 is between 33.44 and 321 ppm, the concentration of CO is between 5 and 100 ppm, the concentration of PM10 pollutant is between 2.68 and µg/m3 97.66, ​​and the concentration of dry dust between 53.23 and 31896 mg/m3 was reported in the five investigated industries. For environmental assessment, 40 environmental aspects were identified using the William-Fine technique. For pollutants CO, SO2, NOx, PM10 and dry particles according to the risk priority number (RPN) calculated and according to the results of the category length, 4 risk classes were obtained with titles of very high, high, medium and low risk. Based on the ranking of 40 environmental aspects, the frequency of low category was 22, average category was 4, high category was 4, and very high category was 10. In gypsum units No. 3 and 4, the risks of PM10 suspended particles were among very high risks. Also, the risk related to dust dry in both chimney of factory No. 5 was reported at a very high level.

The concentrations of carbon monoxide, sulfur dioxide, nitrogen oxides, and dry dusts are lower than the standard values ​​of the Environmental Protection Agency (EPA) related to chimney emissions (carbon monoxide: 435 ppm, sulfur dioxide: 800 ppm, nitrogen oxides: 350 ppm and Dry particles: 600 mg/m3). The concentration of PM10 based on the standard of the World Health Organization (WHO) was higher than the permissible limit (50 µg/m3), while it was lower than the permissible limit based on the EPA (150 µg/m3). The entry of PM10 suspended particles into the atmosphere and also the accumulation of dusts in the environment around the factory is one of the important environmental problems of gypsum factories. Based on the classification, 55% of the aspects were at the low risk level, 10% of the aspects were at the medium risk level, 10% of the aspects were at the high-risk level, and 25% were at the very high-risk level. Finally, in order to reduce the level of risk and for the effective management of these industries, measures such as changing the used fuel to clean fuel, regular monitoring of the quantity and quality of the exhaust gas flow from the industrial chimney, using filter masks when in contact with dust, replacing bag filters Impact type with jet pulse type is remarkable.

The purpose of this research is to measure air pollutants (especially PM10) in Beyhaqi Terminal of Tehran and to model the release of this pollutant under various conditions.

In order to measure the pollutant of suspended particles with a diameter of 10 microns (PM10), a portable device model Grimm 108/109 was used. In the selected points, sampling was done once a month during the year, three days a month and 3 times a day, and the sampling was done at different times of the day, i.e. morning, noon and evening, according to the increase and decrease of vehicle traffic. And for the purpose of modeling, Austal view, version 7 software was used.

The results showed that the concentration measured in the autumn and winter seasons was higher than the first six months of the year. Since in the standard of the World Health Organization, the daily limit for this pollutant is 50 micrograms per cubic meter, it can be seen that in the first scenario, in some areas (distances less than 300 meters from the source), the concentration of the pollutant exceeded the standard. The rest of the ranges are within the standard range. In the second scenario and based on the emission reduction factor of 70%, it was determined that all areas are within the standard range.

Finally, reducing the stopping time of cars, not turning on lights and using exhaust absorbent filters will help to reduce the emission of suspended particles.

Metal particles polluting the air cause damage to living things and plants. Plants grown in a dusty environment show signs of damage. Plants are very efficient at trapping atmospheric particles. Depending on the dust load and duration and tolerance of plants to particles, damage and negative changes may occur in leaf surface, leaf structure and plant growth inhibition, reduction of leaf surface and therefore reduction of total biomass. Investigating the pattern of changes and adaptation of plant species for resistance and survival in the conditions of stress caused by environmental pollutants is useful and efficient in knowing the performance of species and effective exploitation of species, especially in industrial and urban environments. The elements available to plants in the environment are classified into two general categories: essential elements for survival and toxic and non-essential elements. Metals Ni, Co, Zn, MoMn, Fe, Cu are among the low consumption and essential elements for the survival of plants, and metals Al, Cd, Cr, Hg, Pb are toxic and non-essential elements. The presence of the lowest concentration of unnecessary elements in the environment around plants causes complications and the occurrence of biological reactions in order to deal with and adapt to stressful factors in the plant.

wrong locations and overloading in the steel industry have led to the creation of environmental problems by this industry. Wind direction, turbulent conditions and fluxes in the atmosphere near the earth's surface are among the most important atmospheric factors affecting the distribution pattern of air pollutants after leaving their emission sources. The purpose of this study is to model the spread of air pollution in a steel factory under prevailing wind conditions.

Using meteorological data, prevailing wind conditions, annual and seasonal windrose were modeled by AERMET software. Suspended particles as the most important pollutant in the area of ​​the steel factory were sampled and then analyzed with using the AERMOD model, particle diffusion and dispersion modeling in two time periods of 24 hours and 6 days.

The prevailing winds in this region are in the north, northwest, and southeast directions, and the highest amount of pollution is related to distances of 5000 to 20000 meters from the location of the chimneys and in the direction of the prevailing wind in the region. Also, the amount of air pollution caused by the factory chimney on a 24-hour time scale is lower than the clean air standard.

In this study, the effectiveness of the AERMOD model in the direction of better management and control of air pollutants and reduction of adverse effects on the environment is investigated, and appropriate solutions to reduce pollution are provided.

One of the most common and inappropriate crop residue management practices methods is burning them in fields. In Khuzestan province as one of the major agricultural regions in Iran, many farmers burn the crop residue after harvesting which results in the emissions of pollutants and greenhouse gases to the air, soil depletion, reduction of inputs productivity, and other adverse consequences. In this study, the total crop residue being annually burned was estimated based on Modis satellite images, annual statistics, field surveys, and interview with farmers. The results obtained from the process and correction of Modis satellite images in Khuzestan province indicated that the minimum area of farms in which crop residue was burned during 2017, 2018, and 2019 were 137102, 119705, and 195635 ha/yr, respectively. In 2019, burning 1259005 tonnes of dried crop residue emitted 1525760 t CO2, 54560 t CO and 6953 t particles less than 2.5 ppm. The amounts of other air pollutants such as CH2, NOx, N2O, NH3, SO2, NMVOC, BC, and OC were 2146, 3747, 91, 1213, 466, 4920, 2139, and 1293 t, respectively. Preservation of crop residue on the surface can mitigate the air pollutant emissions as well as reducing soil erosion and water use, improving soil fertility and compaction, and finally increasing crop yield. A proper crop residue management practice is achievable by developing agricultural mechanization and adopting conservation agriculture principles.

One of the most important concerns that arises with the increasing development of industries and factories in today's societies is the issue of environmental pollution. In developed western countries, serious efforts have been made to develop technology to reduce pollutants caused by industrial processes. In developing countries, however, efforts to advance modern industries and technologies as fast as possible have prevented them from addressing environmental issues. One of the important causes of pollution is the process of cement production in factories. According to the obtained statistics, in our country, unfortunately, the environmental effects of cement factories have become a controversial and serious issue. Although the country's environmental organization has considered the permit limit for the polluted emitted materials, which is considered as one of the most important and necessary industries in most industrial areas of the world, but in any case, by creating appropriate solutions in the cement industry, the amount of these materials can be Reduced as much as possible and prevent serious human and herbal consequences. Harmful gases and hazardous particles that are released daily by industrial units in the environment are one of the problems of the environment nowadays. Today, industrial activities have caused many changes in the environment, including air pollution with particulate matter and harmful gases. The cement industry, meanwhile, plays an important role in upsetting the balance of natural life and creating environmental anomalies. Pollutants from cement factories mainly include emitted dust and toxic gases. Dust from cement factory smoke disrupts metabolic activity in plants and can affect plant growth and development. The purpose of this study was to investigate the pollution status of Sepahan Cement Industrial Unit in terms of suspended particles and environmental gases. In this study, it was not possible to access the space or area of the study industry (Sepahan Cement). Also, with the performed investigations, the dust particles from the cement were not observed so much that it could be visually accumulated so that it could be sampled. Therefore, the status of suspended particles and ambient gases in different parts of Dizicheh city were measured and checked using portable devices. Then, the data were analyzed using Excel software and also using the standard table of clean air presented in Iran approved in 2016. In this standard, the average concentration per hour was used for carbon monoxide, the average annual concentration for ozone and nitrogen dioxide, and the average 24-hour concentration for suspended particles and sulfur dioxide. For other pollutants, a similar method was used according to the presented standard. Then, by comparing the concentrations of pollutants in Sepahan Cement Factory with the clean air standard approved in 2016, the status of gases and suspended particles in the air around the factory was investigated. It should be mentioned that this research is a descriptive-sectional method with the purpose of checking the concentrations of (SO2), (NO2), (O3) and (CO) gases and suspended particles: (PM10) and (PM2.5) in the surrounding air of 9 stations of Sepahan Isfahan Cement Factory has been done. According to the comparison of the measured values with the allowed limits, it was determined that NO2 gas and SO2 gas in 67% of the studied stations are beyond the permit limit and are considered pollutants. Particles less than 2.5 microns in all stations are less than the allowed limit and are not polluting, but suspended particles less than 10 micron in all stations are more than the permit limits and are considered as environmental pollutants. In the data checking in relation to the permit limits, the parameters beyond the permit limit have been specified and their concentration in relation to the allowable limit was calculated. According to the results, NO2 gas showed 1.7 to 2.6 times the permit limit and SO2 gas showed 1.4 to 3.2 times the permit limit in the studied stations. Particles less than 2.5 microns were less than the permit 24-hour and 10-year limits and showed no pollution. In contrast, particles larger than 10 microns were more than the permit limits compared to the 24-hour limit (1.12 to 3.88 times) and 20 years (2.4 to 4.85 times) and showed a pollution. Among the measured suspended particles at 9 stations around the cement factory , 10% of the suspended particles were related to particles smaller than 2.5 microns and 90% of the suspended particles were related to particles smaller than 10 microns. Among the ambient gases, the highest amount with 80% was related to carbon monoxide (CO) and the lowest amount (4%) of the ambient gases of the cement factory was related to nitrogen dioxide (NO2). According to the average results obtained from the measurement of ambient gases and suspended particles and also compare to the standard of clean air in Iran approved in 2016, sulfur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3) was above the standard value While the CO level was much lower than the standard level. Suspended particles below 2.5 microns were below the permit limit in all stations. But suspended particles below 10 microns were higher than allowed in all stations. The results showed that in most stations around the factory, suspended particles smaller than 10 microns and sulfur dioxide (SO2), nitrogen dioxide (NO2) were higher than the permit limits, which according to these results and the effect of these particles and gases with high concentration, surely the residents around the factory will also be harmed and face negative effects. In general, the concentration of (SO2) and (NO2) gases is higher than the standard of clean air in Iran and the high concentration of these gases can have many negative effects on residents and plants around this factory. Therefore, in order to reduce the negative effects of these gases on people living in the area and plants, Sepahan Cement Factory must provide the conditions to reduce these gases and particles in the environment by creating and installing the necessary equipment.

In the present study, to investigate the air pollution of the Persian Gulf Special Economic Zone in the west of Bandar Abbas, at first inversions which occurred between 2010 and 2020 were extracted using radio sound. Next, using the AERMOD model, the concentration of PM2.5 - 10, SO2, CO and O3 emissions from 60 chimneys for inversion days in a radius of 20 km was predicted. The results showed that the highest inversion was in January and February with 28 and 26 days per month and the lowest with 11 and 13 days in August and July, respectively. The lowest base of the inversion layer was related to January and February with 10 and 13 m, respectively, and the highest with 408 m was in September. The average annual inversions were 250.8 days per year, which 157.4 were radiation and 93.4 were subsidence. The AERMOD model showed that the concentrations of PM2.5, SO2 and O3 were higher than standard, but PM10 and CO were lower than standard. Southeast winds are the most important parameter in the distribution of pollutants, which causes the smoke column move to the northwest. Predicting the distribution of pollutants can be useful in formulating strategic management in environmental protection and sustainable development.

Considering that conducting studies on the emission and concentration of pollutants in the air is one of the key measures to maintain the quality of the environment and, of course, towards the goals of sustainable development, so it can be said that by studying air pollution in industry Oil, to be able to predict the situation of sensitive areas in the future and to deal with possible adverse events, to provide appropriate ways to prevent, deal with and mitigate the consequences. This complex is located in the main flower path of Ahvaz city and directs the exhaust gases directly from the flares of this complex to the western part of Ahvaz. This is a non-interventional and descriptive-analytical study that was conducted in the summer of 1398 in Ahvaz. Ahvaz city with a population of 1059461 people was located at 31.20 north latitude and 48.40 degrees east longitude. The province is arid and semi-arid in terms of weather conditions and is affected by winds from neighboring countries, especially Iraq, as well as winds originating in the Persian Gulf.

After conducting comprehensive studies on the climatic and geographical situation of Ahvaz city and according to the map of Ahvaz flower garden, the exhaust gases from the flares of oil and gas exploitation complex No. 3 in the west of Ahvaz, were considered as a source of pollutants. This complex consists of an operation section with gas and diesel fuel consumption and 3 long burners, 3 short burners and 70 fuel pits, a desalination section with gas fuel and has 2 short burners and a gas pressure boosting station with gas and diesel fuel. It consists of 2 long burners, 1 cold burner and 1 fuel pit. Concentrations of NO2 and CO2, SO2, CO were measured by Enviro SA and Ecotec analyzes. Monitoring of gases and suspended particles was measured in summer and once a month (3 times in total) at intervals of 50, 100, 500, 1000, 2000 and 3000 meters in four directions north, south, west and east of the complex. Figure 2 shows the location of the sampling location. In order to calculate the AQI index, the information obtained from the sampling points according to the table of national standards of open air quality and air quality index were converted into the standard mean time concentration. According to these standards, a maximum concentration of 8 hours was used for carbon monoxide, a maximum concentration of 1 hour for nitrogen dioxide, and a mean concentration of 24 hours for suspended particles and sulfur dioxide. The maximum concentration of CO gas was measured during 24 hours. A maximum concentration of 8 hours and a maximum concentration of 1 hour were used for ozone, an average concentration of 24 hours for suspended corn and sulfur dioxide, and a maximum concentration of 1 hour for nitrogen dioxide. The results of the values related to air hygienic quality indicators of O3, NO2, SO2, CO gases in summer along with changes in air hygienic quality are shown in Table 3. Accordingly, in summer, SO2 gas was very unhealthy up to a distance of 50 meters and NO2 and CO gases were unhealthy up to a distance of 500 meters. CO was very unhealthy at 2000 and 3000 meters in the east, NO2 at 1000 meters east and south and So2 at 3000 meters. O3 gas except at a distance of 50 meters south (Golbad route) with a rate of 0.098 ppm and at a distance of 50 meters west with a rate of 0.09 ppm and a distance of 100 meters east of the complex with a rate of 0.082 pm which was unhealthy In other respects, he was clean and healthy. The quality of PM2.5 particles was 50 meters north and south, 2000 meters south, north and east and 3000 meters in four directions of unhealthy pollution. Healthy condition was measured only in the east direction of Feller at distances of 500 and 1000 m and in the west direction at a distance of 1000 m. PM10 particles except at a distance of 50 m in the south (unhealthy for sensitive groups), 2000 m in the east, south and north (unhealthy for sensitive groups) and west (very unhealthy), 3000 m in the east and north (Unhealthy for sensitive groups) and west (dangerous) showed health in other directions and distances. The case of NO2 gas had Ip index in the distances of 50 and 100 areas to the west and south, a distance of 500 to the north and a distance of 1000 meters in the east at a distance of 2000 and 3000 meters in the west and north. O3 gas at the distances of 100, 50, 500 and 1000 meters had the highest value of Ip index in the south and at the distances of 2000 and 3000 meters in the west (Figure 4). So2 at distances of 50 and 1000 meters in the east and at distances of 100 and 500 meters in the south, at distances of 2000 and 3000 meters in the north and west (Figure 5) and CO at distances of 50 meters in the north, at distances of 100, 500 and 1000 Meters in the south and between 2000 and 3000 meters in the west had the highest Ip index. The Ip index was highest for PM2.5 particles at distances of 50, 100, 500 and 1000 m in the south and in the direction of west at 2000 and 3000 m (Figure 7). The Ip index for PM10 particles was highest in the west at distances of 50, 100, 500, 2000 and 3000 m and in the south at a distance of 1000 m (Figure 8). PM2.5 particles in the west direction and PM10 particles mainly in the east direction had the lowest amount of suspended particles, which is indicated by arrows.In terms of air quality index, PM2 .5 particles in healthy to very unhealthy condition and PM10 particles except at one point in the west at a distance of 2000 and 3000 meters, which showed very unhealthy and dangerous condition in most parts of the healthy condition. In the case of PM2 / 5 particles, which can be justified due to the location of Ahvaz in a dry area and the wind from the surrounding dry areas, which is also associated with light dust particles, also in the west direction, high vehicle traffic on the Ahvaz-Dezful road The access road to the industrial town is also the license plate exchange center, and in the south and southwest of Meyvan va Tarbar Square, as well as Al-Ghadir Stadium and the air defense residential areas, the cause of the high degree of air pollution is particles. The point that is determined by the overlapping of the values of the indicators with the sampling location map is the increase in the intensity of pollution according to the existing urban infrastructure at any point in a way that in the west of Feller by distance from Feller to Up to a radius of 1000 meters due to the lack of urban facilities, a decrease in air quality index gases and suspended particles was observed, but in the range of 2000 and 3000 meters with increasing urban activities and vehicle traffic centers such as fruit and vegetable center and highway. Ahvaz - Dezful and license plate replacement center, the level of pollution with CO and NO2 gases increased, and in fact, these infrastructures play the role of a flare with high CO gas emissions. While in the range of 1000 meters in all four directions of Feller and also 500 meters in the east of Feller and the north due to the existence of agricultural lands and limited rural populations, indicators of a better situation compared to points 50 and 100 Meters near the complex. Also, the situation of So2 gas at a distance of 2000 meters was clean and at a distance of 3000 meters, respectively, it became unhealthy twice. The city can reduce the concentration of this gas in the air and reduce its concentration due to the lack of natural barriers in the area and the lack of new sources of pollution, but at a distance of 3,000 meters of roads act as a new source and they increased the load of So2 contamination.

According to the above findings, the presence of oil and gas exploitation complex No. 3, along with the high density of urban service centers such as stadiums, fruit square and central transport of Ahvaz, license plate replacement center, Modares highway and busy road Ahvaz - Dezful and with Paying attention to the direction of Golbad acts as an aggravating factor for the residents of western Ahvaz, which can lead to many health injuries for citizens, even in the short term, including the short-term and acute effects of PM2. 5.2, NO2 and CO were noted for respiratory disease and mortality as well as due to the presence of farms on food crops.

Heavy metal pollution of airborne particles is a serious problem in the urban environment and has been considered by many researchers. Among heavy metals, lead is an element that enters suspended particles from various sources. In this research, the amount of lead in suspended particles indoor and outdoor the building of Karaj metropolis has been investigated.
Material and

Sampling of suspended particles was performed in December 2019 from 23 stations indoor and outdoor the building in Karaj metropolis. In order to measure the amount of lead in the collected samples, wet chemical digestion method was used by nitric acid/perchloric acid combination. Finally, the concentration of lead metal was measured using ICP-MS.

Based on the findings of this study, the highest levels of lead indoor and outdoor the buildings were measured as 858.73 and 446.28 μg/g, respectively. Also, a significant difference was observed between the amount of lead indoor and outdoor the building and in addition between different stations, in some stations the amount of lead indoor and in some stations outdoor the building the amount of this element was measured more.
Discussion and

Lead analysis in indoor and outdoor dust samples in Karaj metropolis shows the spatial distribution of this pollutant in different stations based on pollutant sources. Examination of the results of one-way analysis of variance test showed that in areas with higher traffic load, the amount of lead in dust samples collected inside and outside the building was higher than other stations.

Recently, aerosols as one of the air pollutants (with natural or anthropogenic sources) have received increasing attention. In this study, the purpose is investigation of soil potential in production of dust (aerosol) storms using wind rose and storm rose.

Meteorological data and WRPLOT view software were used to draw the wind rose and hurricanes. Also, in order to study the wind direction on dusty days, the data of the Meteorological Organization and also to investigate the effect of meteorological parameters such as gentle wind percentage and prevailing wind percentage, statistical methods such as regression relationship, Pearson coefficient have been used. Also, the trend of annual and seasonal changes in the concentration of suspended particles (dust) has been studied in order to determine the seasons with the highest frequency of dust occurrence.

The results indicated that winds blow from northwestern and west in all seasons. The highest frequency of winds is western. The wind roses of spring and summer indicated that the most frequent direction of prevailing winds are western to northwestern. Southeastern direction comes in next level. These storms are more frequent in winter and autumn seasons. Also, investigation of storm roses demonstrated that dominant winds have speed of less than 4.5 meter per second (80%). This research shows that in study area, winds cannot erode the soil and product the aerosols.

Therefore, the main source of recent dust must be searched in the neighboring countries.

Considering the importance of cement industries in the country's economic growth and its effect on emissions of air pollutants (particulate matter); in this research, the effects of Tehran cement factory on the environmental of the region have been investigated. The main purpose of this study is an assessment of environmental pollutant particles with air quality index in 2016 in Tehran Industrial Cement Complex. 

In this study, the particulate matter PM10 and PM2.5, was measured during a one-year period (2016), in four different seasons. To measure dust particles in the ambient air of the device is used gauge 531 MET ONE GT TSI Manufacturing Co and it has the ability to measure particles with PM10, PM2.5, PM7, and PM1. The next 8530 TSI Dust Trak II counterparty bombing device is a desktop dust-removing device that has the capability to record data. The samples were taken at 6 measuring stations in the Tehran Cement Industrial Complex, and finally, the results were evaluated as a seasonal AQI. In AQI method, which is one of the most widely used methods for assessing the air quality, at first, the pollution index is measured at a station and then determined at all stations as the highest index of contamination quality.

The first finding from the present study was that the pollutant responsible for the whole spring station was a refinery, which is classified as clean. The other pollutant responsible for the entire summer stations related to the road toll (Healthy classification), Responsible pollutant for the entire autumn season station area (unhealthy classification for sensitive groups), and Responsible pollutant for the whole winter season is related to residential buildings (Healthy Classification). So the most polluting plants or four different seasons of the year is autumn PM2.5.

So the state of air quality with an average concentration of 106.2 mg/m3 in the Tehran cement industry classified as unhealthy for sensitive groups and were characterized by the orange color. Finally, suggestions are made to reduce particulate emissions in the industrial area.

The atmosphere is a dynamic and complex natural gas system whose pollution kills humans more than others. Air pollution occurs when large amounts of suspended particles or harmful substances enter the atmosphere. Suspended particles with a diameter of fewer than 2.5 µm (PM2.5) are among the most important air pollutants. Black carbon (BC) particles are one of the most important and dangerous components of PM2.5 suspended particles. The aim of this study was to analyze the behavior and time-space distribution of BC pollutants in Iran using the data of the MERRA-2 base model during a statistical period of 40 years (1980-2019). 

In this study, black carbon data in NetCDF format with initial monthly and spatial time steps of 0.5° x 0.625° were first extracted from the Earth data website. After extracting the data, qualitative control, pre-processing and, processing operations were performed. Then, the calculations were performed on monthly and seasonal matrices (on 740 pixels or networked points) using the facilities that the user's software applications ArcGIS, Grads, and Origin pro provide. In the last step, steps were taken to create raster, vector, charts layers and, information tables and the desired outputs were prepared.

The use of MERRA-2 base model data has provided very good results of the spatio-temporal distribution of BC in Iran. The results of the study showed that the monthly and seasonal differences were significant. In terms of monthly differences, the highest amount of BC was estimated in December and the lowest in June. Among the seasons, the highest and lowest levels of BC were related to the winter and summer. Spatially, the highest distribution of BC was observed in the western half of Iran, especially in the metropolises of Tehran and Ahvaz. Analysis of the time series of BC concentrations in the Iranian atmosphere showed that the concentration of this pollutant increased during the statistical period and this increase occurred especially from 2000 AD onwards. Also, in the study of meteorological parameters affecting the concentration of BC, the results showed a significant positive correlation between the concentration of BC and air pressure and a significant negative correlation with wind speed.

The results showed a clear understanding of the concentration of BC in the Iranian atmosphere. We showed that BC pollution is affected by some meteorological parameters such as air pressure and wind speed. In general, regardless of the mechanisms of development, nature, and emission of this pollutant in different parts of Iran, the behavior of the concentration of this pollutant in the context of time indicates the warning of its danger in large parts of Iran. Therefore, it is necessary to take the necessary management and executive measures to reduce this pollution, especially in metropolitan areas with high concentrations of BC.

Isfahan is one of the most contaminated cities in Iran due to its special geographical conditions, topography and proliferation of pollutants. Industries, traffic, domestic and commercial pollutants are considered the main sources of air pollutants in Isfahan. The methods used to predict and estimate air pollution are methods interpolation. The aim of this study is to investigate the scattering patterns and modeling of particular matter PM2.5 and PM10 in the city of Isfahan using interpolation IDW and Cokriging methods.

in this study, the concentration of PM2.5 and PM10 pollutants in winter and summer of 2018 were measured at 137 points of urban area and in linear path by portable device measurement of air pollution (CEM model). Zoning maps for each pollutant in the cold and hot season were in Arc GIS 10.6 environment. In order to verify the accuracy of 30% of the data, the RMSE in both methods was compared.

the result of pollutants distribution with important emission sources, such as high traffic areas and close areas were consistent with the zayanderood river route. Cokriging method has better performance than IDW method in values of RMSE, although in the validation process, there was little difference between fitting the IDW and Cokriging methods.

in the zoning maps, hot spots of pollution (maximum concentration) were observed in central regions of the study area, which is a major contribution to most of the vehicles around the city.

This is a cross-sectional descriptive study with the aim of Measure and determine the concentration of suspended particles: PM10 PM1; PM2.5; And NO2 gases; SO2; CO; HC in open air six important passenger terminals and traffic jams in the metropolis of Tehran.

Using portable device MET ONE to measure suspended particles and the portable device Aeroqual to measure gases in the course of one year, from autumn 94 to summer 95. Samples were analyzed using software SPSS; EXEL.

The results of this study showed that the highest concentration of suspended particles was PM1 with an average of 1.20 micrograms per cubic meter; PM2.5 with average of 6.72 micrograms per cubic meter; PM10 with an average of 100.23 micrograms per cubic meter; CO concentration with a mean concentration of 6.95 ppm, NO2 with a mean concentration of 0.05 ppm, SO2 with an average of 0.05 ppm HC, with an average of 2.56 ppm in winter.

The reasons for the increase in pollutants include: low temperature, no wind blowing, air reversal, terminal location, surrounding pollutants and type of fuel and technology used on buses. Using the results of this research, we can devise appropriate methods for controlling and reducing air pollutants with the aim of improving the system in these sites.

Destructive gases and hazardous particles that are released daily by industrial units into the environment are one of the problems in today's environment. This descriptive cross-sectional study aimed to investigate the concentrations of gases (SO2), (NO2), (O3) and (CO) and particulate matter (PM10) and (PM2.5) at different stations and at different months of the year in the air around the Shahid Montazeri power plant in Isfahan. The results showed that the highest amount of pollutants in the cold months of the year and concentrations of (SO2), (NO2) and (O3) gases were higher than the Iranian air standard, which high concentration of these gases had many negative effects on crop and rangeland surrounding this plant. Carbon monoxide (CO) was the most abundant (88%) of the plant's environmental gases, with a concentration lower than Iran's Air Standard. Suspended particles below 2.5 microns and below 10 microns were below the permissible limit at all stations. Also in the air quality index (AQI) survey, all environmental gases (except SO2) and particulate matter were within the safe range.

Particulate matters are one of the most important air pollutants in Tehran and very dangerous for hu-man health according to the epidemiological studies. The ambient particles contain heavy metals, some of which are toxic and carcinogenic components. Therefore, in this study, the content of heavy metals in airborne particulate matters)PM4(of Tehran was measured and the related health risk was assessed.

Sampling of PM4 was conducted every six days using Chrono PM Sampler with a 10 L/min flow rate at two residential areas including Tehranpars in the east and Ekbatan in the west of Tehran. The concentration of PM4 was calculated with Gravimetric analysis. After the preparation of the samples using the extraction solution)HCl and HNO3(, the concentration of heavy metals was measured by ICP-MS. The metal rich-ness was assessed using the enrichment factor. For health risk assessment of heavy metals in PM4, excess cancer risk was calculated.

At both sampling stations, the highest concentrations in all PM4 samples were related to Al and Fe due to the high abundance of these elements in the earth’s crust. The results of the enrichment factor indicated that Al, Fe, Ti and Mn in PM4 had low enrichment degree and the source of these metals might mainly be the earth’s crust. Ni and Cr had a high enrichment degree. In addition, Zn, Pb, Cu, Sn, As, and Cd had a very high enrichment degree and were mainly anthropogenic. The concentration of PM4 was not significantly different between the two stations in the east and west, but the comparison of the mean concentration of metals in PM4 samples between the two stations showed that the concentrations of Mn, Cu, Sn, Ni, and As at the eastern station were significantly higher than the western station. The comparison of the enrichment factor between the two sam- 
مظلومی و همکاران1399، بهار 1، شماره 18فصلنامه علوم محیطی، دوره 15pling stations also showed that the EF values of the studied elements at the eastern station were higher than those at the western station, which could indicate a higher contribution of anthropogenic sources in the east. Among the studied elements, the highest excess cancer risk was related to Cr)VI(due to its high toxicity. The total excess cancer risk based on the average concentrations of toxic metals in PM4 was 120.1×10-6 at the eastern station and 83.1×10-6 at the western station.

Most of heavy metals in PM4 in the east and west of Tehran had mainly anthropogenic sources and were generated by human activities, especially transportation. The average concentration of heavy metals in PM4at the east of Tehran was higher than the west, and as a result, the excess cancer risk of toxic metals in PM4 was also higher in the east. The most dangerous carcinogenic element in particulate matters of Tehran was Cr)VI(,which should be taken more under consideration and its anthropogenic emission sources must be controlled.

Nowadays, people’s life is at risk because of various pollutants into the atmosphere by human action and biological activities. One of the major air pollutants are particulate matter. The aim of this study was to evaluate spatial interpolation methods to determine the concentration PM2.5 and PM10 in Sabzevar city and select the most suitable interpolation method for preparation of zoning maps particulate matter in GIS.

Particulate matter were measured by a monitoring device, environmental dust model Haz-Dust EPAM 5000 at 48 stations in the city, then in ARC GIS software three well-known spatial interpolation techniques, namely Kriging, Inverse Distance Weighting (IDW) were applied for generating the prediction maps. Finally the best interpolation method was chosen according to the values of each algorithm error.

The results indicated that the RMS was lower between geostatistical and deterministic methods, and the MAPE in deterministic methods was lower.

The best interpolation method for the particulate matter (PM2.5 and PM10) was deterministic method by IDW function.

The term of neural network has evolved to encompass a large class of models and learning methods. They interpret input raw data through a kind of machine perception, labeling or clustering models. They help to group unlabeled data according to similarities among the example inputs, and they classify data when they have a labeled dataset to train on. The neural networks consist of many layers. The layers are made of nodes. A node is just a place where computation happens, loosely patterned on a neuron in the human brain, which fires when it encounters sufficient stimuli. A node combines input from the data with a set of coefficients, or weights, which either amplify or dampen that input, thereby assigning significance to inputs with regard to the task the algorithm is trying to learn. These input-weight products are summed and then the sum is passed through a node’s so-called activation function, to determine whether and to what extent that signal should progress further through the network to affect the ultimate outcome, say, an act of classification. If the signals pass through, the neuron has been “activated.” A node layer is a row of those neuron-like switches that turn on or off as the input is fed through the net. Each layer’s output is simultaneously the subsequent layer’s input, starting from an initial input layer receiving your data. Pairing the model’s adjustable weights with input features is how we assign significance to those features with regard to how the neural network classifies and clusters input. Ensemble methods aim at improving the predictive performance of a given statistical learning or model fitting technique. The general principle of ensemble methods is to construct a linear combination of some model fitting method, instead of using a single fit of the method. Ensemble classifier has two common

Bagging and boosting that they are non-Bayesian procedures. They can be used to improve the accuracy of Classification & Regression Trees. Boosting and bagging are two ensemble models capable of squeezing additional predictive accuracy out of classification algorithms. When using either method, careful tuning of the hyper-parameters should be done to find the best balance of model flexibility, efficiency & predictive improvement. Bagging uses a simple approach that shows up in statistical analyses again and again — improve the estimate of one by combining the estimates of many. Bagging constructs n classification trees using bootstrap sampling of the training data and then combines their predictions to produce a final meta-prediction. In this way, boosting creates successive base classifiers that are told to place greater emphasis on the misclassified samples from the training data. Like bagging, the results from all boosting base classifiers are aggregated to produce a meta-prediction. Compared to bagging, the accuracy of the boosting ensemble improves rapidly with the number of base estimators. Boosting method has many different algorithms that Least Squared Boosting (LSBoost) model was used to improve prediction model in this paper. Discussion of Results &

In the first step, for implementing and evaluating the research’s suggested method, Tabriz bazaar was chosen as the world’s biggest, most important and most complicated covered spaces. As the most important reasons for this choice the large dimensions of this historical bazaar, its complicated structure, presence of a wide range of tradespeople and different occupiers in bazaar, citizens’ and tourists’ referral all year long can be mentioned. Then different information related to Tabriz bazaar’s various passages and buildings including Passage’s length, passage’s width, proportional population density, surface material, presence or absence of ventilation, user’s diversity, distance from nearby streets, roof’s height, temperature and proportional humidity was recorded via field observation. Afterwards training data were collected for neural network. This was done in 86 points with different conditions with the help of a Japanese sensor named Pocket PM2.5 sensor which can evaluate PM2.5 and PM10 pollutants in the range of 0-999 (μg/m^3 ). Collected data for both of the pollutants were classified based on the present standards and place’s conditions in four healthy, medium, warning and dangerous classes and was shown by one to four tags. Given that determining parameters like the number of hidden layers, the number of neurons, the number of replications, the kind of transferring and tutorial functions in neural networks’ utilization is very important and effective, to determine them optimally a code in matlab coding language was used that not only it checks all the feasible functions and the appropriate number for neurons and layers, but also it determines their best amounts. By making multilayer neural network it is possible to predict dispersion in various conditions of pollutants’ amounts. In this paper due to users’ requirement for noticing the pollutant’s class and increasing accuracy the Round operator was used for classificating the results to four classes one to four. Due to the low accuracy of the results, ensemble classifier was used to improve the network. LSBoost model of Ensemble algorithm with the help of 100 boosted decision trees has obtained very appropriate results for this paper’s case study with a learning rate of one (η=1). for performing the neural network in training and network creation phase, data were divided into three sections of train, validation and test data that the way of mean squared error’s convergency and result’s accuracy were evaluated for each of the PM2.5 and PM10 pollutants. Efficient network was choosen by convegency’s speed, performance and accuracy. Due to the implementation the best network for PM2.5 pollutant was determined by two hidden layers (first layer with 9 neurons and transfer function of poslin and second one with 5 neurons and transfer function of tansig) with traincgb’s train data and general accuracy of 97.67% and MSE of 0.385. Also for PM10 pollutant with a hidden layer containing 4 neurons, transfer function of tansig and train function of trainlm with the general accuracy of 97.67% and MSE of 0.2779 was obtained. Traincgb function of Conjugate gradient backprogation with Powell-Beale restarts and trainlm of Levenberg Marquadrat algorithm is a combination of Gauss-Newton and gradient descent which uses the ability of both algorithms and has a high speed in training. It should be noted that in addition to the aforementioned networks, the Ensemble classification algorithm was run on this paper’s data which was resulted to accuracy of 67.44% for PM10 and to accuracy of 68.60% for PM2.5 that indicates the optimality of the compositional approaches used in this study. In other words by using combinational algorithm Ensemble and backpropagation multilayer neural network, the accuracy of results have been improved about 30%. Then based on the collected data in different conditions, the training was done for PM2.5 pollutant with the help of Newff-Ensemble neural network and for PM10 with the help of Feedforward-Ensemble network and prediction was done for other 995 locations of bazaar and PM zoning map was prepared. Based on these maps it is clear that most of the center zones of Tabriz bazaar has appropriate air quality. Some sections of bazaar including bazaarche shotorban, bazaarche yakhchal, chaharsog sadegieh, bazaar dalaleh zan bozorg, raste bazaar sadegieh, karvansarayeh shazdeh bozorg, dalan khan and bazaar jambor ha were in 4th class because of particulate matters and attendance of people who suffer respiratory disorders. Based on collected data for this study and by checking the results of this paper’s proposed model, four criteria Passage’s length, proportional population density, presence of ventilation, user type have been much more effective in increasing particulate matters’ class . So due to the obtained results from this study, areas which are located in dangerous class, effective and serious solutions should be done. For example related to the construction of these areas, modern or classic ventilation systems can be installed to improve the quality of bazaar’s indoor air.

Exhaust emissions resulting from the motor vehicles have harmful and long lasting effects on both the human health and environment. Pollution in different floors of parking through the corridors and stairs will be transferred to other parts of the building and will create problems for the residents. The present study proposes a air quality monitoring system which measures and calculates the ppb value of ten gases including SO2, NO2, NOx, O3, CH4, H2, CO, NH3, Benzene, and Alcohol. Furthermore the particulate matter was measured through a particle counter instrument in parking different floors. The data collected has been compared. There is a direct relationship between the number of parked cars in the parking and the concentration of pollutants. Since Vehicle is the source of regulated pollutants majority of CO, NOx and HC and contributes to the formation of inhalable particulate matter emissions (PM10 and PM2.5) as well as being most source of carbon dioxide (CO2) (CETESB 2013). Therefore Concentration of pollutants varies with the number of vehicles.