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    Effect of time-activity patterns and microenvironments on the personal exposure of undergraduate students to black carbon
    (Springer, 2022) Uzun, Burcu; Onat, Burcu; Ayvaz, Coskun; Akın, Özcan; Şahin, Ülkü Alver
    In this study, the personal exposure to and potential dose of black carbon (BC) of undergraduate students (22-27 years old, nonsmokers) were determined. BC was continuously measured by a portable device (microAeth (R) AE51) for four consecutive days in Istanbul between April and May 2019. The time-activity diaries filled out by each volunteer were assessed to define the activities and microenvironments (home, school, transportation and entertainment) that contributed to daily BC exposure. The overall mean concentration of BC was 2.0 mu g/m(3), and the mean concentrations on weekdays and weekends were 3.0 mu g/m(3) and 1.1 mu g/m(3), respectively. Transportation made the highest contribution to mean BC exposure (42%) and dose (45.8%) on weekdays, while the contributions of home-based activities to BC exposure (66.1%) and dose (63.2%) were higher on weekends. Students had the most intense exposure to (2.8% and 4.6%) and dose (3.1% and 5.8%) of BC in transportation both on weekdays and on weekends, respectively. Between transportation modes, the mean BC concentration was the highest for minibuses (14.8 mu g/m(3)), while walking made the largest contribution to BC exposure (16.8%) on weekdays. Students spent 12.8% of their weekdays at school, and the contributions of the school environment to BC exposure and dose were 8.5% and 7%, respectively. Exposure to BC increased during cooking and eating activities in microenvironments such as the kitchen, cafe and dining hall.
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    Volatile organic compound concentrations under two different ventilation structures and their health risks in the adhesive tape manufacturing workplace
    (Springer, 2023) Sahin, Ulku Alver; Ogur, Nurgul Elif; Ayvaz, Coskun; Dumanoglu, Yetkin; Onat, Burcu; Uzun, Burcu; Ozkaya, Fazilet
    Exposure to the high volatile organic compounds (VOCs) concentration in the workplaces where solvents are used is an essential point for worker's health. However, the VOCs in the indoor air of an adhesive tape production facilities that use large amounts of solvents and the health risk of the toxic compounds have not been sufficiently investigated to this date. VOC samples were collected in the morning and afternoon times of day in the indoor air of workplaces of an adhesive tape production facility at 9 different points under two different central ventilation conditions. Carbon dioxide, humidity, temperature, flow rate, and pressure values were measured continuously throughout the work time with an average recording period of 1 min. The total VOC value had a wide range from 0.1 to 138 mg/m(3). BTEX (benzene, toluene, ethylbenzene, xylenes) contribution to total VOC accounted for between 40 and 60% and the toluene, methylepentane, and trichloroethane concentrations among the sampling points and campaigns dominated the total VOCs. The total hazard quotient (HQ) values for each measurement campaigns were higher than the acceptable limit of 1.0, while the lifetime cancer risk (LCR) values for benzene and carbon tetrachloride were lower than the acceptable limit of 1.0x10(-6). This observational study suggests that the effective and efficient operation of the workplace ventilation systems and the feasibility of the designed ventilation systems are essential on the accumulation of toxic compounds in the air and must be well evaluated.