2023 CiteScore: 1.9
eISSN: 2476-3071
Editor-in-Chief:
Ramin Nabizadeh Nodehi, Ph.D.
Vol 7 No 2 (2022): Spring 2022
Original Research
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Introduction: Volatile Organic Compounds (VOCs) are the most significant
indoor pollutants that mainly emitted from various building materials and
can do a great harm to human beings. The present study aims to the effect of
different shapes of building materials on the emission characteristics of VOCs
by using Computational Fluid Dynamics (CFD) simulation.
Materials and methods: The indoor air flow is described by the continuity
equation, the momentum equation and the standard k-ε model. The transport
of VOCs in materials is described by a transient diffusion equation. ANSYS
Fluent is used to solve the governing equations.
Results: The emission of VOCs from planar building materials is validated
based on the experimental data according to the literature. The numerical
results have proved that the emission VOCs from hollow cylindrical building
materials is faster than that of VOCs from planar building materials. The
thinner the building materials and diffusion coefficient is bigger, the faster
decrease rate of VOCs it is.
Conclusion: The material shape has a significant impact on the emission of
VOCs from building materials. When assessing indoor air quality, the realistic
shape of materials should be used instead of the simplified planar materials. -
Introduction: Presently, air pollution is viewed as a critical environmental challenge that has deleterious effects on human health and ecosystems. The subway system is extensively developed in numerous countries with the
objective of minimizing traffic congestion and pollutant emissions. The aim of the present study is to explore the impact of metro activities on air pollution and, subsequently, urban vegetation inside the two metropolises of Tabriz and Shiraz in comparison to prior years.
Materials and methods: To assess air quality before and after the establishment of the metro, we collected average data for Particulate Matters less than 2.5 µm (PM2.5), Particulate Matters less than 10 µm (PM10), SO2,
NO2, O3, and CO, as well as the Air Quality Index (AQI), retrieved frommonitoring stations in Tabriz and Shiraz between 2014 and 2019. We used the average of the Normalized Difference Vegetation Index (NDVI) calculated by the Landsat 8 satellite in the second phase in order to numerically determine the status of urban vegetation across two timeframes.
Results: Preliminary evidence revealed that the average concentration of pollutants in Tabriz, excluding NO2, fell after the launch of the metro system in 2016. Simultaneously, several pollutants, including O3 , NO2, and PM2.5, and consequently the AQI, increased following the subway's establishment in Shiraz in 2017. Moreover, it was observed that decreasing emissions in Tabriz amplified vegetation, whereas reducing air quality in Shiraz lowered the NDVI values.
Conclusion: Although it appears that the metro's operation improved environmental conditions in Tabriz, a similar outcome was not evident in Shiraz. Therefore, it is suggested that future studies consider meteorological variables whenever addressing the metro's efficiency. -
Introduction: Noise pollution caused by vehicles is one of the major environmental problems in cities and has harmful effects on residents. The aim of the study was to examine the noise pollution in high traffic areas of the city of Ilam and finally to propose solutions.
Materials and methods: This descriptive-analytical and cross-sectional study was performed in the spring of 2020 in three shifts in the morning, noon, and evening at the beginning and end of the week in Ilam city. According to the Iranian standard by Department of Environment in residential and commercial-administrative areas, noise measurement was performed with CEL-440 sound level meter in seven high-traffic points. In this study, the factors affecting noise pollution caused by traffic were recorded in the form of a checklist.
Results: In morning shift at the beginning of the week with the noise level of 70.59 dB, in the noon shift at the beginning of the week with 71.74 dB, and in the evening shift at the beginning of the week with 68.37 dB has a higher noise level. A comparison of sound pressure levels in the morning, noon, and evening shifts at the beginning and end of the week showed no significant difference (P=0.26).
Conclusion: Ilam city has high noise pollution in commercial-residential and commercial-office areas, which was evaluated beyond the standards of noise limits in the open air of Iran. Solutions have been proposed to reduce noise pollution from residents at the measurement points. -
Introduction: The upward movement of Carbon dioxide (CO2) mass into the air and downwards towards the earth's surface, especially vegetative areas, affected the variability of CO2 concentration in the ambient air. In this pattern, this study aimed to determine the net cumulative value of CO2 concentration (Net_CO2-Con) in an urban area to assess the adequacy of greenspace.
Materials and methods: This research method uses CO2 concentration observations within 24 h in 137 observation locations covering an area of 350 km2 in Surabaya city. The sampling location was set at a height of 2 m above the local ground. The CO2 concentration observations were carried out in the dry season and the rainy season for a total of 640 air samples.Results: The results of this study obtained Net_CO2-Con values for ambient CO2 concentrations in a daily pattern. Starting at night there was a flow of CO2 flux into the air, which reached its peak in the morning, in about 90% of the city area. This event was evidence of a lack of CO2 absorption due to the lack of extensive vegetative areas. On a bright day the CO2 flux flows towards the land, which indicated the presence of vegetation absorption in addition to soil absorption. The seasonal time variability of CO2 flux density had the same pattern for the daily time variability.
Conclusion: Mapping for CO2 flux could be an approach to determine the adequacy of greenspace. Areas of upward movement of CO2 flux density were priority areas for greenspace intensification. -
Introduction: Today, with the industrialization of societies, the expansion of urbanization and the increasing trend of population growth, sustainable livelihoods are severely polluted and unfortunately around the world,
especially in developing countries, urban air quality is declining. This study is designed to determine the concentration of PM2.5 particles and the effect of meteorological parameters in 14 selected points in the metropolis of Ahvaz.
Materials and methods: The sampling of Particulate Matter less than 2.5 µm (PM2.5) was in four seasons (winter, spring, summer and autumn). Sampling was performed using the Environmental Protection Agency, method TO-13A (EPA/TO-13A) guideline. Particle samples were collected on a fiberglass filter with a pore size of 1 µm and diameter of 37 mm. Information about meteorological parameters was also recorded by PHB-318. Finally, the obtained data were analyzed by SPSS and R.
Results: The results showed that the concentration of PM2.5 particles in the metropolis of Ahvaz during the study period is 14 times higher than the value of the guidelines of the World Health Organization (WHO). Also, temperature had a negative relationship and relative humidity and pressure had a direct and positive relationship with concentration of PM2.5 particle. It was found that Zargan, Padadshahr 1and 2, Saadi and 17 Shahrivar stations are the most polluted points compared to PM2.5 particles.
Conclusion: Planning appropriate strategies of air pollution control to reduce is important and necessary. -
Introduction: Air and its invisible components play a significant role in the existence of living beings. The two factors of urbanization and industrialization of cities lead to an increase in the concentration of various compounds in the air. This study has been designed and performed to examine seasonal Characterization, Spatial distribution and health risk assessment of sixteen Polycyclic Aromatic Hydrocarbons (PAHs) and eleven Heavy metals bounded PM2.5 at 16 sites in Urban Air of Tabriz, Iran.
Materials and methods: glass-fibre filters, peripheral pumps and PMI holder were used with a total 3 L/min flow rate for 24 h sampling PM2.5 every four seasons at 16 sites from 20nd February to 20th December. Proper solvents are consumed for extraction purposes of these Materials. ICP-OES and GC/MS devices used for analyzing purposes and the spatial distribution of PAHs and heavy metals bounded PM2.5 investigated by ArcGIS10.3 software. ELCR values and carcinogenicity risk were also calculated for children and Adults in different exposure pathways.
Results: The annual mean concentrations of PM2.5 were 41.17 µg/m3, ∑16PAHs bounded-PM2.5 were much higher in autumn and winter (217.47 and 178.32 ng/m3) compared to summer and spring (162.61 and 131.89 ng/m3). The annual mean concentrations of Heavy metals bounded-PM2.5 were 138.69 ng/m3. Dermal carcinogenicity risk of exposure with PAHs was high, and ELCR values of Heavy metals also indicated a high risk for adults and children in some stations.
Conclusion: considering the topographic location of the region, Industrial areas and the frequent presence of temperature inversion, such comprehensive researches are needed for assessments and control policies.
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Introduction: Coronavirus disease 2019 (COVID-19) is a global pandemic level, respiratory system targeted virus infection. The impacts of smoking habits, genetics, and chronic medical conditions such as lung cancers on COVID patients has been assessed extensively so far. However the role of the ambient air quality as a vital factor of life, in COVID 19 mortality risk is not yet properly studies. The association and correlations between ambient air quality and mortality risk has been assessed in this study at a preliminary scale using basic statistical analysis in India and United States of America (USA); two countries with highest COVID prevalence in the world.
Materials and methods: Pearson's Chi-squared test for independence was employed to assess the associations and CramerV statistics was used to evaluate the strength of associations between mortality and air quality. Pearson's product-moment correlation and Spearman's rank correlation were employed to assess the correlation between ambient air quality and deaths.
Results: In the study, the risk of mortality appeared to be significantly dependent on the level of ambient air quality in both countries. However the strength of association was significantly low in both cases. The correlation between ambient air quality and mortalities in both countries also appeared to be significantly low. However the correlation in USA appeared to be higher than in India.
Conclusion: Based on above results it can be concluded that the risk of mortality is dependent on ambient air quality, but air quality might not be the only dominant definitive factor for mortality. However further research might be required at pathological level to theorize the above relationship. -
Introduction: Regular physical activity and outdoor leisure provide significant health benefits. In urban environments, issues related to the air microbiological quality have become a priority due to the pandemic situation we are experiencing. This study analyzed the aerial microbiota of outdoor public spaces, using a qualitative and quantitative approach in Brazilian coastal town.
Materials and methods: Three intra-urban areas were analyzed and characterizing according the thermo-hydrometric characteristics and vegetal cover. Bioaerosols were collected during the wet and dry seasons using the passive sampling technique with selective growth media for fungi and bacteria. Microbial groups were quantified on agar plates; colonies were randomly selected, purified and classified. The antibiotic resistance was evaluated against 6 antibiotics belonging to 6 classes.
Results: Bacteria were relatively more frequent than fungi in the three areas. Among isolates, bacteria represented from 76% (P1) to 90% (P3) ofthe suspended microbiota in the rainy season; in dry season, the percentages varied from 87% (P1) to 91% (P2 and P3). Genus Bacillus was the main representative of Gram positive and Enterobacter genus the most frequently identified among Gram-negative bacteria. Aspergillus and Penicillium genera were the dominant among fungi. Fifty per cent from bacterial strains analyzed were resistant to at least one of the tested antimicrobials.
Conclusion: Bacteria proved more abundant than fungi and more susceptible to climate and environmental changes in the leisure areas of the city. The monitoring of biological agents in the air is important for environmental management and population health.
