Publications (2)4.33 Total impact
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ABSTRACT: The present study investigated the indoor concentrations of selected volatile organic compounds (VOCs) and formaldehyde and their indoor emission characteristics in newly-built apartments at the pre-occupancy stage. In total, 107 apartments were surveyed for indoor and outdoor VOC concentrations in two metropolitan cities and one rural area in Korea. A mass balanced model was used to estimate surface area-specific emission rates of individual VOCs and formaldehyde. Seven (benzene, ethyl benzene, toluene, m,p-xylene, o-xylene, n-hexane, and n-heptane) of 40 target compounds were detectable in all indoor air samples, whereas the first five were detected in all outdoor air samples. Formaldehyde was also predominant in the indoor air samples, with a high detection frequency of 96%. The indoor concentrations were significantly higher than the outdoor concentrations for aromatics, alcohols, terpenes, and ketones. However, six halogenated VOCs exhibited similar concentrations for indoor and outdoor air samples, suggesting that they are not major components emitted from building materials. It was also suggested that a certain portion of the apartments surveyed were constructed by not following the Korean Ministry of Environment guidelines for formaldehyde emissions. Toluene exhibited the highest emission rate with a median value of 138 μg m(-2) h(-1). The target compounds with median emission rates greater than 20 μg m(-2) h(-1) were toluene, 1-propanol, formaldehyde, and 2-butanone. The wood panels/vinyl floor coverings were the largest indoor pollutant source, followed by floorings, wall coverings, adhesives, and paints. The wood panels/vinyl floor coverings contributed nearly three times more to indoor VOC concentrations than paints.
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ABSTRACT: To date, studies on the degradation of gas-phase pollutants by fin-installed photocatalytic reactors are limited. The present study investigated continuous-flow annular photocatalytic reactors installed with fins for efficient removal of four gaseous monocyclic aromatic compounds using two different photocatalysts (unmodified titanium dioxide [TiO(2)] and S-doped TiO(2)). The average degradation efficiencies, which were calculated by comparing benzene, toluene, ethyl benzene, and o,m,p-xylene concentrations measured at the photocatalytic reactor inlet and outlet, obtained from the 6-h photocatalytic process of a nine-fin-installed unmodified TiO(2)/ultraviolet (UV) system were 63%, 76%, 81%, and 90% for benzene, toluene, ethyl benzene, and o, m, p-xylene, respectively; for the unmodified TiO(2)/UV system without fins, the degradation efficiencies were 31%, 45%, 53%, and 56%, respectively. For the nine-fin-installed S-doped TiO(2)/visible-light system, the efficiencies were 30%, 43%, 55%, and 73%, respectively; for the no-fin S-doped TiO(2)/visible-light system, the efficiencies were 13%, 24%, 34%, and 46%, respectively. These results demonstrated that fin-installed photocatalytic reactors enhanced the degradation efficiencies for all target compounds and that the degradation efficiencies increased gradually with an increasing number of fins. In addition, under the present experimental conditions, both input concentrations of target compounds and flow rates were found to be important parameters for the photocatalytic mechanism of these fin-installed photocatalytic units. Average degradation efficiencies obtained from the six-fin unmodified TiO(2)/UV system decreased as the input concentrations increased. Similarly, degradation efficiency decreased as the flow rate increased.
Kyungpook National University
Daikyū, Daegu, South Korea
- Department of Environmental Engineering