Higher moisture content associated with the greater emission of DEHP from the plastic wallpaper

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(1)Session ID: 76 │ Paper ID: 776. Higher moisture content associated with the greater emission of DEHP from the plastic wallpaper. Dept. of Environmental and Occupational Health College of Medicine, National Cheng Kung University. Tainan. Nai‐Yun Hsu1,*, Yu‐Chun Liu1, Chia‐Wei Lee2, Ching‐Chang Lee1, Huey‐Jen Su1 1 Department of Environmental and Occupational Health, Medical College, National Cheng Kung University, Tainan, Taiwan 2 Department of Safety, Health and Environment Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung, Taiwan. *Presenter: [email protected]. Introduction Increasing frequency of extreme precipitation and flooding events is found globally. Previous studies indicated that higher concentrations of phthalate esters in the household settled dust were associated with self‐reported presence of water leakage (Bornehag et al. 2005). In Taiwan, increased di‐(2ethylhexyl) phthalate (DEHP) level was also related to the problems of water damage or visible mold on wall inside the buildings (Hsu et al., 2012). However, the effects of the moisture on the phthalate emission from building materials are still underreported. This study aimed to evaluate the effect of moisture content (MC) on the level of the DEHP emitted from the plastic wallpaper within 15 days in the closed chamber. The scenario of occupants’ short‐term exposure profile of the phthalate in the indoor environment after suffering from water damage was simulated.. Material and methods. The five most used polyvinyl chloride (PVC) coated wallpapers in the market are analyzed for DEHP concentration, and the one with highest level (2160.67 mg/g, 0.22%) was adopted in the current study. Wallpapers of standard size were put in the 2.4 liter airtight chamber set up with the magnetic stirrer to mix air [Figure 1]. A total five chambers with three conditions varied by MC levels of wallpapers were tested: (1) control chamber without wallpaper (2) dry wallpaper with MC at 3.57 ± 0.22% (original status) (3) damp wallpaper with MC at 52.31 ± 2.45% (pre‐treatment of soaking in water for 30 minutes). FIGURE 1. Design of chamber Duplicates were conducted for both of the second and third conditions. The air temperature and relative humidity (RH) was set at 28°C and 100%, respectively.. FIGURE 2. Timeline of the experiment. Fixed volume of RO water was added regularly to well‐control the air RH and wallpapers MC in the five chambers during whole experiment, and with the stability in terms of CV less than 2% and 6%, respectively. Air samples (1 LPM for 1‐hr) were collected at the elapsed time of 2nd, 4th, 6th, 8th, 10th, 13th and 15th day, and wipe samples were collected at the final day [figure 2]. DEHP concentration was analyzed by GC/MS. The mass concentrations of air and wipe samples were calculated by the detected concentration in the sampling tube (µg/mL) multiply the volume of extraction solvent. As to the dust mass levels, the concentrations (µg/g) multiply 1 gram of dust. The ‘total mass concentration’ was the sum of mass concentrations in air, dust, and wipe samples.. Results. (a). (b) FIGURE 3. DEHP concentration in (a) air and (b) dust samples during the experimental period . The average concentrations of air and dust among three conditions were 0.25 ± 0.00, 1.16 ± 0.69, 1.83 ± 2.03 µg/m3 and 0.10 ± 0.05, 0.51 ± 0.20, 0.68 ± 0.26 µg/g [Figure 3], respectively. Higher DEHP concentrations emitted into the air and adsorbed on the dust were found with higher MC in the wallpapers. Although DEHP level detected in the air in this study was relatively low, it had increased with the length of experiment, at the maximum of 15 days. Overall, about 35% higher of total DEHP mass released into air, dust and wipe samples was found in the damp wallpapers compared to that in the dry ones [Figure 4]. It was suggested that the material should be removed within 4 days once it has been damaged by water since the emission of DEHP mass was found to increase from the 4th day [Figure 5].. Conclusion This is the first study to demonstrate the effects of material moisture on the emission of phthalates in the indoor environments. Preventing dampness problem or improving moisture resistance of building materials is not only critical to control microbial burdens but also chemical exposures such as phthalate emissions in indoor environments.. FIGURE 4. Total mass concentration of DEHP among three conditions. FIGURE 5. Releasing mass profile of DEHP within 15 days. This study was partly supported by the Ministry of Science and Technology in Taiwan (MOST 101‐2221‐E‐006‐158‐MY3)..

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