yaghoub hajizadeh

Indoor air quality is a critical factor influencing the health and well-being of individuals in society, as polluted indoor air can lead to various diseases. Consequently, this study examined the awareness, attitudes, and performance of health workers in Khorramabad City, Iran, concerning indoor air pollution, as well as the correlation of these factors with demographic variables.

This descriptive-analytical cross-sectional study was conducted in 2021 using a researcher-developed questionnaire to assess the knowledge, attitudes, and performance of health workers in the health centers of Khorramabad City. A total of 149 individuals from the Khorramabad health center participated in the study, and after receiving education, 140 of them agreed to complete the questionnaire. The collected data were analyzed using independent t-tests, analysis of variance (ANOVA), and Pearson's correlation coefficient via SPSS software.

Health workers' performance regarding indoor air quality had the highest score of 60.50, while the scores for attitude and knowledge were 51.85 and 17.82, respectively. There was no statistically significant difference in the scores of knowledge, attitude, and performance between men and women (P > 0.05). The level of education had a significant relationship with the average scores of knowledge and performance. Consequently, the highest scores in knowledge, attitude, and performance were observed among individuals with a bachelor's degree or higher. In contrast, no significant relationship was found between the scores of knowledge, attitude, and performance with age or work experience.

Given the limited awareness among health workers regarding indoor air pollution, coupled with their significant role in disseminating health information to the community, it is essential to conduct training courses on this topic to enhance the knowledge of health workers.

 In this study, the levels of urinary metabolites of toluene and xylene isomers in pregnant women in Isfahan and Khansar cities and their associations with air quality index (AQI) and demographic factors were investigated. 

 Depending on the population, 55 pregnant women from Isfahan and 15 pregnant women from Khansar, a total of 70 people were enrolled in the study and 140 urine samples were collected during their 1st and 3rd trimesters of pregnancy (autumn and spring). Urinary metabolites of hippuric acid (HA), ortho-, meta-, and para-methyl HA (o-m-p-MHA) were extracted by dispersive liquid-liquid microextraction method, derivatized and analyzed using gas chromatography/mass spectrometer. The results were statistically correlated with AQI level and demographic factors using appropriate statistical methods. 

 Mean urinary concentrations of HA, o-m-p-MHA in the 1st trimester of pregnancy were 371.2, 1.14, 2.48, and 1.97 mg/g cr, and those in the 3rd trimester were 582.1, 3.54, 6.93, and 2.43 mg/g cr, respectively. In the 1st trimester, the mean urinary level of ortho-MHA was significantly associated with the outdoor exposure time on workdays and fragrances use (P < 0.05). In the 3rd trimester, the mean concentration of HA was significantly correlated to age and outdoor exposure time on workdays (P < 0.05). 

 The mean urinary concentrations of HA and MHA isomers in the 1st trimester of pregnancy in Isfahan were more than those in Khansar. Because the level of air pollution in Isfahan was higher than Khansar and that in autumn was higher than spring. In the 3rd trimester of pregnancy, the mean levels of MHA isomers in Isfahan were more than those in Khansar. Only the amount of p-MHA was significantly associated with AQI in the 1st trimester of pregnancy. Thus, women who lived in high-traffic urban areas with high AQI were more exposed to toluene and xylene compounds.

Context: 

At the beginning of the COVID-19 pandemic, the effects of personal protective equipment (PPE) such as face masks, as well as environmental conditions, including temperature and humidity changes, were discussed due to the lack of effective medicine.

 The preferred reporting items for systematic reviews and meta-analysis (PRISMA) were implemented to conduct the present systematic review. The articles were selected from papers published by May 2020 in PubMed, Web of Science, Science Direct, Scopus, and Google Scholar databases. This meta-analysis estimated relative risk (RR) and pooled mean depicted as effect size (ES) using the random or fixed effects methods.

 Ten studies met inclusion criteria, four of which addressed the effect of face masks and six of which dealt with temperature and humidity changes. This eta-analysis study showed that wearing face masks against the COVID-19 virus had a remarkable safety impact with RR (%95 CI) 8.56 (2.10 - 34.90), (I2 = %0.0 P = 0.999), and the pooled mean changes in temperature and humidity were estimated to be with ES (%95 CI) 9.03 (4.32 - 13.74), (I2 = %99.7, P = 0.0001) and with ES (%95 CI) 56.82 (46.12 - 67.51), ( I2 = %99.3, P = 0.0001) during the outbreak of the COVID-19.

 The findings of this systematic review and meta-analysis illustrate the effectiveness of face masks, in general, in preventing the transmission of the COVID-19 virus. According to the findings, temperature and humidity changes do not increase the outbreak of the COVID-19 virus.

The atmospheric suspended particulate matter is a major route of human exposure to different kinds of environmental pollutants especially toxic heavy metals. The aim of this study was to assess the carcinogenic and non-carcinogenic risk of cadmium in dry deposition of atmospheric dust in Qazvin, Iran.

Glass traps were used for sampling dry atmospheric dust. To determine the concentration of cadmium (Cd), the samples were injected into ICP-OES after preparation. Then, the risk of carcinogenicity and non-carcinogenicity of Cd was calculated in children and adults.

The mean concentration of Cd was 0.0164 mg/kg. Cumulative non-carcinogenic risk (HI) in all exposure pathways for children and adults were 2.31E-4 and 1.94 E-4, respectively. The cumulative carcinogenic risk (TCR) in children and adults were 4.72 E-9 and 9.21 E-9, respectively.

The risk of carcinogenicity and non-carcinogenicity due to the presence of cadmium in atmospheric dust and exposure in children and adults was found to be lower than acceptable limits. However, due to increasing air pollution in the future, it may cause harmful effects to the health of citizens.

This study aimed to review the impact of climate change around the world on the incidence of emerging and noncommunicable diseases in sensitive and vulnerable individuals, such as pregnant women and newborns. The combination of keywords such as climate change, ambient temperature, pregnancy outcomes, spontaneous abortion, preterm birth, stillbirth, autism, orofacial cleft, cleft palate, heart disorders, and diabetes was used for comprehensive search on reputable citation databases such as Scopus, PubMed, Web of Science, and Google Scholar, throughout research conducted previously with a focus on the years from 2018 to 2020. The results of the literature cited showed that long-term exposure to high temperatures reduced birth weight. Heat has been reported to have serious adverse effect than cool weather for preterm birth. A significant association has been reported between seasonal changes and diabetes and gestational hypertension. Climate changes, by increasing infant mortality and miscarriage, have made a difference in sex ratios. Further, the development of neonatal abnormalities such as hypospadias, autism, cleft palate, and heart disorders has been significantly associated with climate change. Seasonal changes, rising temperatures, sunlight, increased ultraviolet rays, and ozone concentration have been suggested to involve in the prevalence of cleft palate. Changes in relative humidity, temperature, sunlight, oxygen pressure, and elevated environments have also contributed to the development of heart disorders. This review showed that climate change has played an important role in the incidence and prevalence of emerging diseases. Hence, climate change has adverse effects on pregnant women and neonates. This study confirms critical importance of climate change and its negative effect on susceptible people and next generation.

 Urban expansion has caused lots of problems such as air pollution, which endanger the health of residents. In this research, the spatiotemporal trend of atmospheric fine particulate matter (PM2.5) of Isfahan was studied and modeled using distributed space–time expectation–maximization (D-STEM) software in 2017. 

 This software uses a flexible hierarchical space–time model that can deal with multiple variables and massive loads of missing data. Model estimation is based on the expectation–maximization algorithm. The effects of confounder variables such as holidays, altitude, average temperature and relative humidity, rainfall, wind speed, and direction were considered in the modeling. The hourly measured ambient PM2.5concentration data were obtained from seven air pollution monitoring stations installed in different zones of Isfahan and operated by the department of environment. 

 The distribution map of the pollutant demonstrated two polluted areas located in southwest and southeast regions of the city that are high traffic and densely populated area. PM2.5concentration was significantly increased (P < 0.05) with an increase in land elevation by a coefficient of 0.93; conversely, it decreased significantly (P < 0.05) with every increase in wind speed by a coefficient of −0.226. 

 Given the spatiotemporal correlations between air pollutant data, it is necessary to incorporate these correlations into model to obtain more accurate estimates. Using the statistical models and methods to manage the data, time, and volume of calculations in spatiotemporal estimations, the D-STEM program gives more accurate estimates of the desired parameters. Presenting models and maps for every desired time period are another feature of this software that can be useful in health programming and environmental management. Vehicular traffic had a significant effect on the increasing trend of the pollutant level in urban areas; however, the effects of atmospheric phenomena such as dust storms and thermal inversion cannot be ignored.

In addition to chemical contaminants, the air we breathe may contain various microorganisms that can cause infectious and allergic diseases. This study aimed to evaluate the concentration of bioaerosols in indoor and outdoor air of school and kindergarten buildings in Andimeshk, Iran. Moreover, the indoor-to-outdoor concentration ratios (I/O) were calculated to identify the sources of contamination during winter 2016.

In this cross-sectional descriptive study, 216 air samples were taken from the indoor and outdoor of the school and kindergarten buildings during winter 2016 (i.e., January, February, and March) in Andimeshk, Iran. The sampling was performed using an Andersen single-stage impactor containing a culture medium and an SKC Pump based on the methods recommended by the American Conference of Governmental Industrial Hygienists. Bacterial samples were incubated at 37°C for 2 days and fungal samples were stored at room temperature for 3 to 5 days. Subsequently, the colonies were counted and reported as the colony counts per cubic meter (CFU/m3).

The school No.4 obtained the highest mean of indoor (1504 CFU/m3) and outdoor (1295 CFU/m3) bacterial concentration. Moreover, kindergartens No. 4 and 3 obtained the highest mean of indoor (249.6 CFU/m3) and outdoor (323.3 CFU/m3) fungal concentration, respectively. In addition, the lowest mean of indoor (513.5 CFU/m3) and outdoor (221.6 CFU/m3) bacterial concentration were related to school No. 6 and kindergarten No. 5, respectively. In the same line, kindergarten No. 5 obtained the lowest and highest mean of indoor (147.6 CFU/m3) and outdoor (174.3 CFU/m3) fungal concentration. The highest mean (46.2 CFU/m3) of indoor fungal concentration (i.e., Aspergillus fumigatus) was related to school No. 1, and the lowest mean (4.61 CFU/m3) in this regard was observed in kindergarten No. 3.

Based on the results, the mean amount of indoor bacteria concentration at all buildings understudy was greater than that proposed by the World Health Organization (500 CFU/m3). This can be the cause of respiratory diseases and a threat to children's health. A study of I/O in elementary schools and kindergartens showed that the sources of bacterial and fungal contaminations were mostly indoor and outdoor, respectively. Therefore, there is a need for continuous monitoring and developing prevention management programs.

One of the major aspects of waste management is recycling. Planning for recycling requires having an accurate estimation of the knowledge, attitude, and performance of the community about waste recycling. Therefore, this study aimed to investigate the levels of awareness, attitude, and performance of women of Hassanabad city in Isfahan province, Iran towards waste recycling.

This descriptive cross-sectional study was performed using a researcher-made questionnaire as the data collection tool. The validity of the questionnaire was approved by Cronbach’s alpha. The samples were selected through cluster sampling from the study population of women in Hassanabad town. For this purpose, two clusters were chosen randomly from five zones of the city (i.e., north, south, east, west, and center). Each cluster included one region and 25 households were selected out of each cluster. It should be noted that the questionnaire entailed five parts, namely demographic characteristics, awareness, attitude, performance, and satisfaction level. All the data were analyzed using the SPSS software version 22.

Our findings showed that the mean age of the subjects was 38.37±10.9 years. Moreover, the knowledge level was weak, moderate, and good in 20%, 38.4%, and 41.6% of the participants, respectively. Approximately 24.8%, 48%, and 27.2% of the women had weak, moderate, and good attitudes toward recycling, respectively. Furthermore, 49.6% of the individuals showed weak performance, while 34.4% were moderate and 16% were of good performance. It should be noted that the socio-demographic characteristics, including age, education, and family size were significantly associated with the awareness, attitude, and performance of the participants. The satisfaction level of women with the performance of waste management plan was evaluated as moderate.

According to the results of this study, The level of awareness, attitude, and performance of women in Hassanabad city was high, moderate, and low, respectively. Therefore, educational workshops and motivational programs for recycling and improving the performance of urban waste management can result in increased participation and better recycling.

Formaldehyde is a common hazardous indoor air pollutant which recently raised public concerns due to its well‑known carcinogenic effects on human. The aim of this study was to investigate a potted plant‑soil system ability in formaldehyde removal from a poor ventilated indoor air to promote dwellers health.
For this purpose, we used one of the common interior plants from the fern species (Nephrolepis obliterata), inside a Plexiglas chamber under controlled environment. Entire plant removal effciency and potted soil/roots contribution were determined by continuously introducing different formaldehyde vapor concentrations to the chamber (0.6–11 mg/m3) each over a 48‑h period. Sampling was conducted from inlet and outlet of the chamber every morning and evening over the study period, and the average of each stage was reported.
The results showed that the N. obliterata plant effciently removed formaldehyde from the polluted air by 90%– 100%, depending on the inlet concentrations, in a long time exposure. The contribution of the soil and roots for formaldehyde elimination was 26%. Evaluation of the plant growing characteristics showed that the fumigation did not affect the chlorophyll content, carotenoid, and average height of the plant; however, a decrease in the plant water content was observed.
According to the results of this study, phytoremediation of volatile organic compound‑contaminated indoor air by the ornamental potted plants is an effective method which can be economically applicable in buildings. The fern species tested here had high potential to improve interior environments where formaldehyde emission is a health concern.

Policyclic aromatic hydrocarbons (PAHs) mainly release to the air from incomplete combustion of fossil fuels like oil, coal, wood, etc. Because of their bioaccumulation, carcinogenicity and mutagenicity effects, they are one of the major concerns of the scientific community. In this study, the concentrations of PAHs in the ambient air of heavily trafficed areas in Isfahan during summer and autumn seasons of 2016 were measured.
Air sampling was conducted passively using SPME fibres (PDMS).. The SPME samplers were installed in 7 points of selected high traffic areas for 24 hours. After sampling, PAHs adsorbed on the fibres were directly analysed with a GC / TQ-MS device without the need for extraction according to standard methods.
Findings: In the studied samples, maximum ΣPAHs was related to Azadi Square with a concentration of 53.83 ± 4.06 ng/m3 in autumn, and minimum concentration of ΣPAHs was measured at Vahid bridge with an average of 21.82 ± 1.28 ng/m3 in summer. Acenaphthylene over the other PAH concentration was the highest. Based on the results, the average concentration of PAHs in autumn was more than summer.
The results showed that exposures to these compounds via ambient air at all stations, especially in high-traffic areas were higher than those suggested by OSHA, NIOSH and AGCCIH. High level of these compounds in different parts of the city can be attributed to the excessive vehicle traffic as well as the topography of the city. Therefore, traffic management and control of emissions from vehicles can be very effective in reducing PAHs emissions.

The presence of air pollutants such as CO, NO2, SO2, O3, and PM in the ambient air mainly emitted from fossil fuels combustion has become a major health concern. The aims of this study were to estimate the attribution of NO2, SO2, and O3 in the premature deaths and prevalence of cardiovascular and respiratory diseases in Isfahan in 2013–2014.
In this study, short‑term health effects (total mortality, cardiovascular and respiratory mortality, chronic obstructive pulmonary disease, and acute myocardial infarction) of exposure NO2, SO2, and O3 on the population of Isfahan were assessed using AirQ 2.2.3 software suggested by the World Health Organization (WHO).
The result showed that from nonaccident total mortality in 2013–2014 in Isfahan, the attributable proportion related to NO2, SO2, and O3 were 1.03% (109 cases), 3.46% (365 cases), and 1.29% (136 cases), respectively. The percentage of days that people were exposed to the highest concentration of NO 2 (40–49 μg/m3), SO2 (60–69 μg/m3), and O3 (40–49 μg/m3) was 34.46%, 16.85%, and 42.74% of a year, respectively. Total mortality attributed to NO2, SO2, and O3 exposure was 0.36%, 0.79%, and 0.83%, respectively.
The concentrations of NO2 and SO2 were upper than the WHO guidelines. The Air‑Q software in spite of its limitations can provide useful information regarding the health outcome of the air pollutants. The results estimated in this study were considerable. This information can help the health authorities and policy makers to draw suitable strategies and fulfll effective emission control programs.

Increased combustion of fossil fuel owing to the energy requirement is a main cause of air pollution throughout the world. Atmospheric precipitation is considered as a major water resource for indoor, municipal, industrial and agricultural uses. This study was aimed to evaluate the effect of air pollution on chemical quality of rain and snow in Urmia, a city in northwest of Iran.
Sampling was performed during the wet seasons from October to March at six sampling stations in different locations of the city. Acidity, alkalinity, NO3- , SO42-, Cl- and pH contents of the collected samples were analyzed.
All samples showed a pH value of more than 6.8, and lower acidity than alkalinity, therefore, the precipitations were not acidic. Maximum concentrations of SO42- and NO3- in the samples were 5 and 8.8mg/L, respectively. Chloride was varied from 1 to 11.5 mg/L with the highest measures observing in autumn.
According to the results, concentrations of the analyzed parameters in wet precipitations in Urmia were within the natural ranges except chloride ions, which was higher than its common level in the atmosphere. This phenomenon may be the result of desert dusts which transfers by wind from the west border to Iran.

Solid-phase microextraction (SPME) has received much attention as a new approach for air sampling. SPME is an efficient solventless sample preparation method which can be easily applied to a variety of chemical compounds.
In this study, the efficiency and accuracy of SPME method for analysis of benzene exposure inside public vehicles was investigated and compared with results of present analytical and separation methods. In the first phase, different concentrations of benzene were standardized in specific volume of air and the calibration graph was drawn. In the next stage, SPME samplers were installed for specified periods inside and outside the bus. Then, the average concentration of benzene in the air was measured by injection of SPME fiber into the gas chromatography (GC) device.
Findings: Maximum concentration of benzene was about 26 μg/m3 inside the bus and 8 μg/m3 outside the bus. The comparison between measured values of SPME method and adsorbent tubes method provided a high degree of correlation (R2 = 0.98), indicating that SPME method can measure benzene concentration with reasonable accuracy.
According to the present study results, a noticeable increase in the concentration of benzene was observed inside the bus during summer which exceeded the standard level and the measured values of benzene outside and inside the bus during spring, which was at the standard level. The results of the measurements using the conventional method of pumps and absorbent and SPME showed acceptable similarity.

Risk factors of non-communicable disease (NCD) origin from early life, and exposure to environmental pollutant may be a predisposing factor. This study aimed to investigate the association of air quality index (AQI) and fine particulate matter (PM2.5) with some NCD risk factors in a sample of Iranian children and adolescents.
This cross-sectional study was conducted in 2014 to 2016 among children and adolescents, aged 6-18 years, in Isfahan, Iran. Physical examination, including weight, height, and blood pressure, was conducted by standard methods. Fasting blood sample was obtained for fasting blood glucose, total cholesterol, high density lipoprotein-cholesterol, low-density lipoprotein- cholesterol, and triglycerides. The mean AQI and PM2.5 values from the study time till one year prior to the survey were used. Multiple linear regression analysis was conducted for the association of AQI and PM2.5 with other variables.
Participants consisted of 186 children and adolescents with mean (SD) age of 10.52(2.38) years. Exposure to higher level of PM2.5 had significant associations with higher levels of systolic blood pressure, low-density lipoprotein cholesterol, and triglycerides. It also had positive relationship with other risk factors and inverse association with low-density lipoprotein cholesterol (LDL-C), but these associations were not statistically significant. The corresponding figures were not significant for AQI.
At current study results showed that exposure to higher levels of fine particulates was associated with some NCD risk factors in children and adolescents. Early life prevention of NCDs can lead to large reductions in disease risk; adverse effects of ambient pollutants should be considered in this regard.

Air pollution is an important environmental issue due to its proven serious impacts on human health. The aim of this study was to estimate the attribution of particulate matter with an aerodynamic diameters of ≤ 2.5 and 10 (PM2.5 and PM10) in the prevalence of cardiovascular and respiratory diseases and premature deaths in Isfahan in 2013–2014.

This descriptive, ecological study was conducted to assess health impacts of PM2.5 and PM10 on the population using Air Q2.2.3 software, suggested by the World Health Organization (WHO).

The results showed that the annual mean, winter mean, summer mean, and the 98 percentile of PM10 concentration in Isfahan were 108, 100, 116, and 264 μg/m3, respectively. The number of deaths per year related to PM2.5 was 670 and that for PM10 was 713 cases. The number of annual deaths due to cardiovascular and respiratory diseases attributed to PM10 was 316 and 68 cases, respectively.

The results of this study revealed that about 44.3% of total annual death due to cardiovascular diseases and 9.55% of that due to respiratory diseases were attributed to PM10 exposure. In the other word, residents were exposed to PM2.5 and PM10 concentrations higher than the WHO guidelines which caused a notable increase in the rate of mortality.

Various epidemiological studies have shown that exposure to environmental pollutants including polycyclic aromatic hydrocarbons (PAHs) might increase the risk of cardiovascular diseases (CVDs) and their risk factors. This study aims to systematically review the association of PAH exposure with metabolic impairment.
Data were collected by searching for relevant studies in international databases using the following keywords: “polycyclic aromatic hydrocarbon” “cardiovascular disease,” PAH CVD, polycyclic aromatic hydrocarbon and “air pollutant” “CVD,” and the desired data were extracted and included in the study according to the systematic review process.
From the 14 articles included in the present systematic review, eight articles were conducted on the relationship between PAH and CVDs, four articles were conducted to examine the association of PAH exposure with blood pressure (BP), and two articles investigated the link between PAH and obesity.
Most studies included in this systematic review reported a significant positive association of PAH exposure with increased risk of CVDs and its major risk factors including elevated BP and obesity. These findings should be confirmed by longitudinal studies with long‑term follow‑up.

Introduction and Long term exposure to air pollutants can result in the development and acceleration of various conditions, such as cardiac and respiratory problems, reduced lung function, chronic bronchitis, asthma, pulmonary cancer, and even death. Regarding this, the aim of the present study was to perform a spatial analysis of air pollution and mortality in Isfahan, Iran.
In this ecological study, the spatial analysis of particulate matter 10 μm (PM10), PM2.5, ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2) was performed using the geographic information system. Additionally, the evaluation of the premature deaths attributable to these pollutants was carried out through the AirQ software version 2.2.
According to the results of the spatial analysis, the eastern part of Isfahan had higher concentration of air pollutants, compared to other directions. There were 481, 493, 117, 102, and 54 mortality cases attributed to PM10, PM2.5, O3, SO2, and NO2, respectively. In addition, PM10 was found to have the highest health effects among other pollutants.
As the findings of this study indicated, PM10 had the highest concentration in Isfahan city. With respect to the fact that air pollutants accounted for almost 15.8% of the total mortality rate in this city, there is an argent need to adapt some strategies to reduce the emissions of air pollutants.

Background and Today use of unleaded gasoline is increasing in the world which contain abundant amount of aromatic organic carcinogenic compounds. This study aimed at monitoring the temporal and spatial concentration of benzene and toluene as volatile organic compounds in ambient air in Yazd, Iran.
This research, was carried out in different hours of the morning and evening in early fall, 2015. Sampling and measurement of benzene - toluene was done according to 1501 NIOSH guidelines using active sampling and GC-FID. GIS software was used for zoning.
The mean concentrations of benzene and toluene in early and late morning-evening hours were 23 and 48.9 μg/m3, 25 and 58 μg/m3, respectively. These values indicates an increase in emissions in last hours of the morning. Also, toluene to benzene ratio (T/B) was 1.3 to 2.1 and 1.2 to 3, showing that benzene and toluene emissions were caused by traffic.
The central and southern parts of Yazd were found to be more polluted then northern areas. Also, spatial variations of pollutant concentrations were high, but the temporal trend was low. The correlation between benzene and toluene values in early hours of morning and evening confirmed the temporal and spatial trend. According to T/B ratio, the main cause of benzene and toluene emissions were street traffics and gasoline stations.

 This research was conducted to measure the concentration of asbestos fibers in the ambient air of high traffic areas of Isfahan and to evaluate their spatio-temporal variation during summer 2015. 

 Air samples were collected from eleven points covering traffic areas of the Isfahan city including Enghelab square, Azadi square, Bozorgmehr bridge, Ghods square, Ahmedabad square, Artesh square, Emam Hossein square, Nazar junction, Vafaei junction, Felezzi bridge, and Tayyeb fork during 3 months of summer 2015. Scanning electron microscope (SEM) coupled to an energy dispersive X-ray system was utilized to count and identify the asbestos fibers. 

 Seasonal average concentration of airborne asbestos fibers in the studied region was 10.04 ± 4.90 SEM f/l. The results of this study showed that the highest concentration of asbestos fibers was measured in Azadi square (18.08 ± 3.863 SEM f/l) and that the lowest was found in Nazar junction(3.92 ± 1.749 SEM f/l). There was a significant correlation between the concentration of asbestos fibers and atmospheric temperature and humidity (P < 0.05). The mean concentration in September was higher than August and July (11.08 ± 4.66). 

 Heavy traffic in the dense areas of the city, and topographical and meteorological features of the city have a major contribution in asbestos fiber emission which resulted in its exceeded levels from the WHO guideline (2.2 SEM f/l). Therefore, effective strategies such as traffic management, industrial movement, and products replacement can be effective in reducing airborne asbestoses fibers concentrations.

 Levels of asbestos fibers in ambient air of dense areas of Shiraz, Iran, were monitored in winter 2014. 

 Sampling was carried out by directing air flow to a mixed cellulose ester membrane filter mounted on an open-faced filter holder using a low flow sampling pump. Fiber counting on the filters was conducted using both phase contrast microscopy (PCM) method to determine total fibers and scanning electron microscopy (SEM) method to identify nonasbestos from asbestos fibers. 

 The average concentration of asbestos fibers in the ambient air of the study in different areas of Shiraz were 1.18 ± 0.28 PCM f/L and 13.64 ± 2.87 SEM f/L, in which a maximum level was measured in Valiasr square (1.89 ± 0.54 PCM f/L [20.37 ± 5.55 SEM f/L]), and that of in Moallem square was in minimum (1.05 ± 0.47 PCM f/L [12.24 ± 3.04 SEM f/L]). 

 The averages of asbestos fibers in all sampling points were higher than the WHO suggested standards for ambient air (0.05 PCM f/L, 2.2 SEM f/L). This may be attributed to the frequent occurrence of heavy traffic, the existence of relevant industries in and around the city, and the topographic characteristics of the city. Therefore, immediate courses of action such as product substitution, traffic smoothing, and industrial sites relocating should be taken to eliminate asbestos fibers emission.

In the past two decades, epidemiological studies have shown that outdoor air pollution lead to increase in respiratory symptoms, cardiovascular diseases, chronic bronchitis and mortality. This study aimed to estimate AQI index and the risk of cardiovascular and respiratory diseases and premature mortality caused by PM10, PM2.5 and SO2 in Yazd, 2013-2014.

In this ecological-descriptive study the air quality was assessed using AQI index. The health impact assessment of PM10, PM2.5 and SO2 was obtained by AirQ software.

According to the results, PM10 was the main cause of hospital admissions (n=460) and premature death (n=283) while SO2 was observed as the least effective pollutant involving 0.29% hospitalization and 9 premature death. The days with unhealthy air quality (AQI >100) was estimated less than 10 percent per year. The highest values of AQI were observed in spring and summer. PM10 was responsible for high AQI in 11 months and O3 was only responsible in first week of April.

The AirQ showed high rates of premature death, cardiovascular and respiratory diseases associated with PM10 and PM2.5 in Yazd. Unhealthy air quality in some days could be due to fuel combustion, wind, dust, and air dryness.

High concentrations of elements such as aluminum (Al) and silicon (Si) in drinking water can affect human health. It is suggested that high daily intake of Al is associated with increased risk of neurodegenerative disorders. Si, as an antidote of Al, may decrease Al bioavailability. The study was conducted to estimate Al and Si concentration and correlation in water and evaluate their health risk. In this cross‑sectional study, water samples were collected from 20 points of water distribution system and the water treatment plant of Isfahan in spring and summer. Samples were analyzed using DR‑5000. The health risk was evaluated via calculating chronic daily intake (CDI) and hazard index (HI). Significant negative correlation was documented between Al and Si (R = −0.482, P = 0.037 in spring, and R = −0.452, P = 0.049 in summer). These values were approximately similar in all types of Al and Si. The amounts of CDI for Al in spring and summer were 6.67E‑04 and 0.002 mg/kg/day, respectively. The Al HI values were below 1 in both seasons. The significant correlation between Al and Si concentrations suggests that Si can eliminate Al in water, and probably it might do the same in the body. The health risk of Al intake from tap water was negligible, it was assessed in an acceptable range with an HI value of less than the standard levels. The health risk of Si remained unknown due to lack of information regarding its toxicity and adverse health effects.

 Modification of multi-walled carbon nanotubes (MWCNTs) via ozone was carried out to enhance removal benzene from aqueous solutions. 

 Multi-walled carbon nanotubes purchased from the Iranian Research Institute of the Petroleum Industry was oxidized by ozone generator at %80 intensity for 5 min and in 30% NaOCl. 

 The Fourier transform infrared analysis showed that the peaks corresponded to the hydroxyl and carboxylic acid groups in modified MWCNTs (MMWCNTs) are more intense than that in non-MMWCNTs. The images of scanning electron microscopy indicated that the MMWCNTs have a lower degree of entanglement with increased porosity compared to the nonmodified one. X-ray diffraction test showed that structural crystallization was increased following the modification. After modification, the efficiency of MWCNTs was increased by 20%. The optimum condition for initial benzene concentration, MWCNT dose, contact time, and pH was: 100 mg/L, 2000 mg/L, 20 min, and 5 respectively. 

 Our research suggested that ozone modification can be a simple method in improvement of the MWCNTs efficiency for removal of benzene from aqueous solution.

 Feasibility of the anaerobic migrating blanket reactor (AMBR) was investigated for the treatment of composting leachate. 

 The AMBR consisted of a rectangular, plexiglas reactor (inside dimensions: length = 43 cm, height = 23.5 cm, width = 10 cm) with an active volume of 10 L. which divided reactor into four identical compartments (2.5 L). Composting leachate was used as a feed. Start-up of a reactor with diluted feed of approximately 10.43 g/L. Chemical oxygen demand (COD) was accomplished in about 44 weeks using seed sludge from the anaerobic digester of municipal wastewater treatment plant and operated continuously at mesophilic phase. The organic loading rates (OLRs) applied to the system was gradually increased from 1 to 19.65 g COD/L.d. 

 The reactor with hydraulic retention time of 10 day at 35΀C and initial OLR of 1 g COD/L.d showed 82.3% COD removal efficiency. The best performance of the reactor was observed with an OLR of 3.79 g COD/L.d. In influent of reactor, BOD 5 /COD ratio, TSS, VSS and TDS were ranged from 0.47 to 0.69, 1650 to 16,830, 990 to 12,622 and 2630 to 31,240 mg/L and in effluent of reactor were reached to 0.28 to 0.38, 660 to 7452, 346.5 to 4597 and 1860 to 19,490 mg/L, respectively. 

 The AMBR could be an appealing option for pretreatment of organic load in composting leachate and improving the efficiency of the next biological reactors.

 The aims of this study were to monitor the concentration of benzene, toluene, ethyl benzene and xylenes (BTEX) in the ambient air of the city of Shahreza gas stations and to identify the spreading distance of the pollutants from the fueling stations. 

 Sampling was carried out from the air of 10 existing fuel stations, (2 compressed natural gas and 8 gasoline and diesel stations) and points of 50, 150 and 250 m away from the stations during cold and warm seasons in 2013. Air samples were taken via active sampling process using activated carbon tubes, extracted by carbon disulfide and analyzed by a gas chromatograph coupled to a flame ionization detector. 

 The averages of all achieved BTEX concentrations were under/around the permitted guideline levels for occupational exposure. According to the ambient air guidelines, the benzene level was much higher than the suggested levels in all the stations. However, the average concentrations of toluene, ethyl benzene, and xylene were not exceeded from the standards. The seasonal variation had no influence on the concentrations of BTEX. There was no significant difference between the pollutants concentrations at points 50, 150 and 250 m away from the stations. 

 Fuel stations could be the main sources of volatile organic compounds emission in the city of Shahreza. The number and volume of refueling in the gas stations influence the emission rates. Therefore, it is suggested to take preventive actions such as repairing of pumps and tanks leak and installing vapor return systems at the time of fuel transferring.