Multiple comparisons of organic,microbial, and fine particulate pollutants in typical indoor environments: Diurnal and seasonal variations

This study was performed to investigate the possible sources as well as seasonal and diurnal variations of indoor air pollutants in widely used four different environments (house, office, kindergarten, and primary school) in which people spend most of their time. Bioaerosol levels and species, volatile organic compound (VOC) levels, and PM_2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm) levels were determined in different parts of these environments in parallel with outdoor sampling. Air pollution samplings were carried out in each microenvironment during five subsequent days in both winter and summer in Ankara, Turkey. The results indicated that bioaerosol, VOC, and PM_2.5 levels were higher in the winter than in the summer. Moreover, PM_2.5 and bioaerosol levels showed remarkable daily and diurnal variations, whereas a good correlation was found between the VOC levels measured in the morning and in the afternoon. Bacteria levels were, in general, higher than fungi levels. Among the VOCs, toluene was the most predominant, whereas elevated n-hexane levels were also observed in the kindergarten and the primary school, probably due to the frequent wet cleaning during school days. According to factor analysis, several factors were found to be significantly influencing the indoor air quality (IAQ), and amongst them, VOC-based products used indoors ranked first. The overall results indicate that grab sampling in naturally ventilated places may overestimate or underestimate the IAQ due to the inhomogeneous composition of indoor air caused by irregular exchanges with the outdoor air according to the season and/or occupants' habits.

Implications Seasonal and diurnal variations of VOCs, PM_2.5, bioaerosols in house, office, and schools were observed, in which PM_2.5 and bioaeorosols showed marked both intra- and interday variability, but VOCs did not. VOC-containing products were the most common source of air pollutants affecting the indoor air quality. External factors affecting the indoor air quality were season and indirectly ventilation. A grab sample cannot be representative in evaluating the air quality of a naturally ventilated environment precisely.     

Canola straw as a bio-waste resource for medium density fiberboard (MDF) manufacture

Canola straw as an agricultural residue has been investigated for MDF production. The variables were steaming time (2, 5 and 8 min), the resin content (9% and 11%), and press time (4 and 6 min). Common physical and mechanical properties of experimental boards including modulus of rupture (MOR), modulus of elasticity (MOE), internal bond strength (IB) and thickness swelling (TS) were measured. Fiber properties of canola straw including length, diameter and cell wall thickness were determined. The results showed that all the tested mechanical properties improved with the increase of steaming time level. The results were close to the minimum requirements of MDF specified in the ANSI A208.2 standard. Dimensional stability of the MDFs improved as adhesive content increased. The IB values are positively affected by the increase of press time. MDF properties made from canola straw possess acceptable qualities as compared to those made from other non-wood plants. Furthermore, the fiber dimensions of canola straw were also in the range of reported values in hardwoods.     

Phytoextraction and phytostabilization potential of plants grown in the vicinity of heavy metal-contaminated soils: a case study at an industrial town site

With the development of urbanization and industrialization, soils have become increasingly polluted by heavy metals. Phytoremediation, an emerging cost-effective, nonintrusive, and aesthetically pleasing technology that uses the remarkable ability of plants to concentrate elements, can be potentially used to remediate metal-contaminated sites. In this research, two processes of phytoremediation (phytoextraction and phytostabilization) were surveyed in some plant species around an industrial town in the Hamedan Province in the central-western part of Iran. To this purpose, shoots and roots of the seven plant species and the associated soil samples were collected and analyzed by measuring Pb, Fe, Mn, Cu, and Zn concentrations using ICP-AES and then calculating the biological absorption coefficient, bioconcentration factor, and translocation factor parameters for each element. The obtained results showed that among the collected plants, Salsola soda is the most effective species for phytoextraction and phytostabilization and Cirsium arvense has the potential for phytostabilization of the measured heavy metals.     

GIS aided prediction of CO2 emission dispersion from geothermal electricity production

CO₂ is the dominant constituent of non-condensable gases in the steam phase of most geothermal fluids. This paper attempts to present the results of a study conducted to develop prediction modeling of CO₂ dispersion in the surrounding atmosphere from a planned 50 MWe geothermal power plant prior to its production. Dispersion models are widely used for predicting future concentrations of environmental emissions on a range of geographic scales. The dispersion type for gases and their average removal rate depends on the meteorological conditions such as wind direction, wind speed, precipitation, atmospheric stability, and surface roughness and topography. Geographic Information System (GIS) capabilities were used for quality visualization of the model outputs and presenting an accurate numerical copy of the study area. The results by the prediction model show that the natural transfer of CO₂ will be from the power plant toward east and northeast and CO₂ concentration trends after the power plant utilization will be similar to the background conditions with minor changes. This dispersion test was carried out to validate and field test the GIS aided dispersion modeling approach described in the paper and the procedure may be applicable for other studies assessing the emission dispersion of pollutants from a point source.     

Investigation on the adsorption capability of egg shell membrane towards model textile dyes

Adsorption isotherms of Direct Red 80 (DR80) and Acid Blue 25 (AB25) on the egg shell membrane (ESM) were performed at 20 ± 1 °C. Physical characteristics of ESM such as surface area and presence of functional groups were verified. The Fourier transform infra-red (FTIR) spectra proved the presence of fuctional groups such as hydroxyl, amine and carbonyl groups in ESM. The surface area of ESM was found to be 2.2098 m²/g. The effects of operational parameters such as initial dye concentration, pH₀, contact time, particle size and ESM doses were studied. The Langmuir, Freundlich, BET, Redlich-Peterson and Temkin adsorption models were applied to describe the equilibrium isotherms. The pseudo-first-order and pseudo-second-order kinetics models were examined to evaluate the kinetics data at different pH₀ values (2–12) and the rate constants were calculated. Maximum desorption of 81.8% was achieved for both dyes in aqueous solution at pH₀ 12. Also scanning electron micrographs (SEM) of the treated and untreated adsorbent were performed. Results indicate that ESM could be employed as a natural and Eco-Friendly adsorbent material for the removal of trace organics in solutions.     

DRASTIC framework improvement using Stepwise Weight Assessment Ratio Analysis (SWARA) and combination of Genetic Algorithm and Entropy

Environmental Science and Pollution Research - Hybrid and integrated techniques can be used to investigate intrinsic uncertainties of the overlay and index groundwater vulnerability assessment...     

Cigarette butt littering consequences: a study of pollution rate on beaches and urban environments

Cigarette butts are hazardous wastes that are not properly discarded by most smokers. They are one of the most abundant litters in the environment and a threat to various organisms because they leak numerous pollutants. This study aimed to assess the distribution of cigarette butts in a coastal city south of the Caspian Sea in Mazandaran Province, Iran. Observations were performed using the visual survey technique based on standardized protocol. The results showed 11,261 littered cigarette butts in 15 studied urban areas ( an average of 0.306 units per square meter). Also, the average density of littered cigarette butts on the studied beaches was 0.106 per square meter. The littered cigarette butts had significant spatial variation, and the number of counts was 135 to 2090. The land-use has a significant effect on the density of littered cigarette butts due to its population density. The inquiry’s index demonstrated that 33.3% of the studied urban areas are high pollution and severe pollution, while all beaches are high and severe. Therefore, a significant focus must be considered to reduce cigarette butts littering due to the collection problems and challenges of cigarette butt management. Because the pollution on the beaches is higher than in urban areas, improving waste management services and establishing a regular cleaning program are essential.

     

Challenges on the recycling of cigarette butts

Environmental Science and Pollution Research - Cigarette butt (CB) is a crucial litter in urban communities because it may contain various toxicants. Due to serious limitations on...     

CO<Subscript>2</Subscript> emission and economic growth of Iran

This research investigates the relationship between CO₂ emission and economic growth of Iran over 14 years from 1994 to 2007 using a national panel data set. The statistical and emission intensity methodologies are used for analyzing the data series. The study finds evidence supporting parameters which conclude the stability of significant correlation between CO₂ emission and economic development over time during the years under investigation in Iran. This relationship is investigated and discussed for the energy sectors of the country as well. The results confirm that in all sectors except of agricultural, there is a positive strong correlation between CO₂ emission and economic growth throughout the study period. In most sectors, CO₂ emission intensity (the emission per unit of GDP) doesn’t show increasing trends while the absolute emission is rapidly increasing by the economic growth.