WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
Browse
7 results
Search Results
Article Citation - WoS: 10Citation - Scopus: 12Tuning Pendant Groups of Polythiophene on Carbon Nanotubes for Vapour Classification(Elsevier Ltd., 2017) Tu, Meng-Che; Svm, Hari Krishna; Thilini, Alahakoon; Wallace, Lim Tse Loong; Moochhala, Shabbir; Yıldız, Ümit Hakan; Palaniappan, Al.; Liedberg, BoPoly(3-alkoxythiophene) (PT) with varying ratios of triethylamine and 1-methyl imidazole pendant groups and horizontally aligned single walled carbon nanotubes (SWCNT) are utilized in this study for volatile organic compounds (VOCs) classification. PTs with five different ratios of pendant groups are incorporated with SWCNT and are evaluated as chemiresistor arrays for analysis of VOCs such as ethanol, acetone, toluene, chloroform, isoprene and ethylene. Varying PT pendant groups yielded differential SWCNT current responses attributed to their chemical affinities for the VOCs tested. Principal component analysis (PCA) for vapour classification illustrated that the vapour responses are separable, thus, highlighting vapour discrimination ability of SWCNT with controlled ratios of PT pendant groups. The proposed methodology is a facile VOC classification approach for two main reasons; (i) PT could easily modified with various pendants groups containing appropriate chemical moieties for preferential interaction with various VOCs and (ii) increasing the number PTs with appropriate pendant group modifications would provide additional inputs to PCA thereby enabling capturing and assaying of a wide range of VOCs.Article Citation - WoS: 12Citation - Scopus: 15Assessment and Improvement of Indoor Environmental Quality in a Primary School(Taylor and Francis Ltd., 2017) Ekren, Orhan; Karadeniz, Ziya Haktan; Atmaca, İbrahim; Ugranlı Çiçek, Tuğba; Sofuoğlu, Sait Cemil; Toksoy, MacitThis study reports levels of indoor environmental quality variables before and after installation of heat recovery ventilation in a primary school located in an urban area in Izmir, Turkey. A CO2-based modeling was performed to determine the required flow rates that would comply with an international ventilation standard, followed by computational fluid dynamics modeling for best airflow distribution in a classroom. Temperature, CO2, PM2.5, and total volatile organic compounds were found at undesired levels, among which relative humidity, CO2, and PM2.5 were improved after the intervention. Reductions in the mean and maximum concentrations were 29% and 68% for CO2 and 29% and 46% for PM2.5. This intervention study was a part of the city-wide main project that aimed to increase awareness of the students and their families, teachers, and staff regarding importance of indoor environmental quality in both at school and home due to its possible effects on children's health and academic performance, one of the major challenges of today's societies all around the globe.Article Citation - WoS: 41Citation - Scopus: 44Vapor Phase Solvatochromic Responses of Polydiacetylene Embedded Matrix Polymers(Royal Society of Chemistry, 2017) Tu, Meng-Che; Cheema, Jamal Ahmed; Yıldız, Ümit Hakan; Palaniappan, Alagappan; Liedberg, BoThe solvatochromic response of polydiacetylene (PDA) in the vapor phase is enabled upon incorporation with matrix polymers such as polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), polyacrylic acid (PAA), and poly-4-vinylpyridine (P4VP). The matrix polymers provide a soft/gel-like framework for accommodating photopolymerized PDA, while facilitating its conformational alternations upon interaction with preconcentrated volatile organic compounds (VOCs). The matrix polymers enabled the differentiation of VOCs owing to their varying morphology, chemical affinity and solubility in VOCs. The ratios between PDA and the matrix polymers are optimized according to the obtained solvatochromic responses evaluated in varying temperature, humidity and storage conditions. As a proof of concept, a finger-print array for differentiation of 7 VOCs is demonstrated using matrix polymer-embedded PDA. The obtained results indicate that the response time and sensitivity of the proposed methodology supersedes previous reports on solvatochromic VOC assays. Furthermore, the proposed methodology would enable differentiation of a wide range of VOCs upon incorporation of additional matrix polymers with varying sorption properties.Article Citation - WoS: 89Citation - Scopus: 105Spatial and Temporal Variations in Atmospheric Vocs, No2, So2, and O3 Concentrations at a Heavily Industrialized Region in Western Turkey, and Assessment of the Carcinogenic Risk Levels of Benzene(Elsevier Ltd., 2015) Yılmaz Civan, Mihriban; Elbir, Tolga; Seyfioğlu, Remzi; Kuntasal, Öznur Oğuz; Bayram, Abdurrahman; Doğan, Güray; Yurdakul, Sema; Andiç, Özgün; Müezzinoğlu, Aysen; Sofuoğlu, Sait Cemil; Pekey, Hakan; Pekey, Beyhan; Bozlaker, Ayşe; Odabaşı, Mustafa; Tuncel, GürdalAmbient concentrations of volatile organic compounds (VOCs), nitrogen dioxide (NO2), sulphur dioxide (SO2) and ground-level ozone (O3) were measured at 55 locations around a densely populated industrial zone, hosting a petrochemical complex (Petkim), a petroleum refinery (Tupras), ship-dismantling facilities, several iron and steel plants, and a gas-fired power plant. Five passive sampling campaigns were performed covering summer and winter seasons of 2005 and 2007. Elevated concentrations of VOCs, NO2 and SO2 around the refinery, petrochemical complex and roads indicated that industrial activities and vehicular emissions are the main sources of these pollutants in the region. Ozone concentrations were low at the industrial zone and settlement areas, but high in rural stations downwind from these sources due to NO distillation. The United States Environmental Protection Agency's positive matrix factorization receptor model (EPA PMF) was employed to apportion ambient concentrations of VOCs into six factors, which were associated with emissions sources. Traffic was found to be highest contributor to measured ∑VOCs concentrations, followed by the Petkim and Tupras.Median cancer risk due to benzene inhalation calculated using a Monte Carlo simulation was approximately 4 per-one-million population, which exceeded the U.S. EPA benchmark of 1 per one million. Petkim, Tupras and traffic emissions were the major sources of cancer risk due to benzene inhalation in the Aliaga airshed. Relative contributions of these two source groups changes significantly from one location to another, demonstrating the limitation of determining source contributions and calculating health risk using data from one or two permanent stations in an industrial area.Article Citation - WoS: 163An Assessment of Indoor Air Concentrations and Health Risks of Volatile Organic Compounds in Three Primary Schools(Elsevier Ltd., 2011) Sofuoğlu, Sait Cemil; Aslan, Güler; İnal, Fikret; Sofuoğlu, AysunConcentrations of volatile organic compounds (VOCs), including formaldehyde, in classrooms, kindergartens, and outdoor playgrounds of three primary schools were measured in spring, winter, and fall terms in Izmir, Turkey. A health-risk assessment was conducted for odor detection, sensory irritation, chronic toxic effects, and cancer. Active sampling was applied for VOCs and formaldehyde on Tenax TA and DNPH tubes, respectively. VOCs were analyzed in a thermal desorption-GC-MS system. Formaldehyde analysis was performed using an HPLC instrument. Benzene, toluene, and formaldehyde were the most abundant compounds with 95th percentile indoor air concentrations of 29, 87, and 106μg/m3, respectively. Naphthalene and xylenes followed them with an order of magnitude lower concentrations. Two isomers of dichlorobenzene (1,3 and 1,4) were the other notable compounds. The concentrations were utilized to classify the indoor air pollutants with respect to potential health effects. In addition, carcinogenic and chronic toxic risks were estimated using Monte-Carlo simulation. Formaldehyde appears to be the most concerning pollutant with high chronic toxic and carcinogenic risk levels according to the health assessment followed by naphthalene, benzene, and toluene due to their chronic effects.Article Citation - WoS: 42Citation - Scopus: 50Occurrence, Oral Exposure and Risk Assessment of Volatile Organic Compounds in Drinking Water for Izmir(Elsevier Ltd., 2006) Kavcar, Pınar; Odabaşı, Mustafa; Kitiş, Mehmet; İnal, Fikret; Sofuoğlu, Sait CemilConcentrations of volatile organic compounds (VOCs) were measured in the drinking water in Province of İzmir, Turkey, and associated health risks due to ingestion of these compounds were investigated using population weighted random samples. A total of 100 houses were visited in different districts of İzmir and drinking water samples were collected from consumers' drinking water source. Questionnaires were administered to one participant in each house to determine demographics and drinking water consumption rates. Oral exposure and risks were estimated for each participant and İzmir population by deterministic and probabilistic approaches, respectively. The four trihalomethane (THM) species (i.e., chloroform, bromodichloromethane, dibromochloromethane, and bromoform), benzene, toluene, p-xylene, and naphthalene were the most frequently detected VOCs with concentrations ranging from below detection limit to 35 μg/l. The risk estimates were found to be less than the values reported in the literature with few exceptions. Noncarcinogenic risks attributable to ingestion of VOCs for İzmir population were negligible, whereas the mean carcinogenic risk estimates for bromodichloromethane and dibromochloromethane were above the de minimis level of one in a million (10-6). For all VOCs, the concentrations measured in metropolitan area were greater than those in other districts. All THM species were detected in higher concentrations in tap water, whereas nontap water contained more benzene, toluene, p-xylene, and naphthalene. Therefore, the concentrations of the latter four compounds and associated risks increased with increasing income and education level since bottled water was used in larger proportions within these subgroups. The results of this study showed that oral exposure to drinking water contaminants and associated risks may be higher than the acceptable levels even if the concentrations fall below the standards.Article Citation - WoS: 10Citation - Scopus: 14Exposure and Risk Estimates for Arizona Drinking Water(John Wiley and Sons Inc., 2003) Sofuoğlu, Sait Cemil; Lebowitz, Michael D.; O'Rouke, Mary Kay; Robertson, Gary L; Dellarco, Michael; Moschandreas, Demetrios J.As part of the National Human Exposure Assessment Survey, a multistage sampling was used to estimate and compare exposures and risks associated with drinking water for two groups - the population of Arizona and that of border communities. There had been some concern that the border communities' exposures would be higher than those of other parts of the state because of their proximity to Mexico, where environmental quality may not be as high a priority as it is in the United States. The two study populations were further categorized by gender, age, ethnicity, education, income, and building structure type and year of construction. For these subgroups, the study estimated and compared risks for arsenic, 1,3-butadiene, chloroform, chromium, 1,2-dichloroethane, dichloromethane, lead, nickel, and toluene. For almost all of the sample subjects, residue concentrations were below the drinking water guideline values of both Arizona and the US Environmental Protection Agency. Of the metals studied, arsenic was the only one with a population carcinogenic risk above the acceptable level of 1.0E-6. Contrary to expressed concerns, average daily exposures and associated risks were estimated to be smaller in the border communities than in the Arizona population. For utilities, one finding deserving further study was that risks from tap water were estimated to be greater than risks from nontap water. Further research may be warranted to uncover the causes for these elevated risks.