• Journal of the Korea Furniture Society
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• v.14 no.2
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• pp.1-12
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• 2003

This study was carried out to determine the mechanical and physical properties of particle boards glued with condensed tannin (Wattle Tannin) powder that was single-molecule phenolic compounds like powdered phenolic resin. Our findings are; 1) It is necessary to spray water on the chip surfaces for effective application of powdered -form tannin resin. It shows that the best and optimum mat moisture increase is 14% of water spray on the surface of chips for developing PB properties. 2) In general, for both liquid and powdered tannin adhesives, their physical and mechanical properties has been proportional to the increase of resin level. But, the most efficient addition ratio is 16% of resin on dry basis. Specially, it is found that the resin level influences on the amount of free formaldehyde emission. The higher the resin level is, the lower the emission is. These phenomena seem to result from the increase of hexamine or formaline in the adhesives used as a hardener, that reduce the free-formaldehyde amount by reaction of tannin of poly-molecule and water. 3) The optimum condition for manufacturing PBs is the condition of hexamine of 5% and formaline of 6% in mechanical and physical properties. Hexamine is superior to formaline in mechanical and physical properties along with the control of the free formaldehyde emission amount. The result of NaOH's addition is insignificant in all experiments of both mechanical and physical properties.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.375-384
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• 2006

Hairdressers may be exposed to many chemicals from hair dye, permanent, shampoo, hair spray and so on. The study was conducted to evaluate occupational exposure to 8 chemicals (isopropanol, ethanol, xylene, toluene, ethylbenzene, acetone, ammonia and formaldehyde) for workers and levels of these materials in airborne of a hairdressing salon. Since compared to ACGIH TLVs these 8 chemicals were very low, it is thought that there has no problem to occupational exposure to these chemicals. Even if hairdressing salon is not enforced on Korean Standards for Indoor Air Quality, level of TOVC was thought to be below the standards. At the aspect of indoor air quality formaldehyde needs to be controlled in the future. The results imply that emission of isopropanol, ethanol, acetone and ammonia are related with hairdressing job, but emission of xylene, toluene and ehtylbenzene is more related with traditional indoor air pollution than hairdressing job. Sources of formaldehyde is thought to be little related with hairdressing job. HVAC system was a little effective on general ventilation.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.259-263
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• 2004

This study was performed to investigate airborne formaldehyde concentration in preschool facilities. Arithmetic mean of indoor formaldehyde concentration in urban area was 34.9 ppb(Geometric mean 24.4 ppb) whereas outdoor concentration was 21.5 ppb(GM 11.9 ppb). In rural area, formaldehyde concentrations were 36.4 ppb(GM 28.7 ppb), 4.1 ppb(GM 4.1 ppb), respectively. There is no statistical significance between the formaldehyde concentrations of urban classrooms and those of rural area. We verified that the distribution of airborne formaldehyde concentration was log-normal characteristic using Shapiro and Wilk test. The 6.7% of urban indoor samples was exceeded the domestic standard limit of indoor air quality. From our study and other study, we concluded that the major emission sources of formaldehyde in preschool facilities was in indoor rather than outdoor.

• Korean Journal of Agricultural Science
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• v.36 no.1
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• pp.11-18
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• 2009

The purpose of this study is to examine a proper amount of addition and a proper point for addition of titanium dioxide for the manufacture of E0 type of urea-formaldehyde resin (UF). The reduction of free formaldehyde from UF resin treated particle board was also investigated. $TiO_2$ content was 0.5%, 1% and 3% on the dry basis of UF resin. UV light was used to initiate reaction. The results of this study are as follows: 1. During UF resin manufacturing process, the second adding step of urea was proper point for $TiO_2$ addition. 2. 1 % addition of $TiO_2$ gave good values for the Eo type urea-formaldehyde resin. 3. There was no significant difference between physical properties of particle board, but the higher the adding content of titanium dioxide resulted in the lower the mechanical properties.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.139-142
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• 2013

A study was carried out to evaluate the solid phase micro-extraction (SPME) for formaldehyde emission analysis of uncoated plywood. In SPME, formaldehyde was on-fiber derivatized through headspace extraction and analyzed by gas chromatography coupled with mass spectrometry (GC/MS). The SPME was compared with desiccators (DC-JAS 233), small-scale chamber (SSC-ASTM D6007) and liquid-liquid extraction (LLE-EPA 556) methods which were performed in accordance with their respective standards. Compared to SSC (RSD 4.3%) and LLE (RSD 5.0%), the SPME method showed better repeatability (RSD 1.8%) and not much difference from DC (RSD 1.4%). The SPME has proven to be highly precise (at 95% confidence level) with better recovery (REC 102%). Validation of the SPME method for formaldehyde quantitative analysis was evidenced. In addition, the SPME by air sampling directly from plywood specimens (SPME-W) correlated best with DC ($r^2$ = 0.983), followed by LLE ($r^2$ = 0.950) and SSC ($r^2$ = 0.935).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.3
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• pp.397-412
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• 1996

This study aims to present the fundamental strategies to improve the Indoor Air Quality (IAQ) in apartment buildings. To investigate the concentration of indoor air pollutants such as radon, formaldehyde, and VOCs, both the document survey and the field measurement were conducted. In addition, to identify the source of the air pollutants, the laboratory experiment was carried out for various building materials. Finally, the minimum period to be reserved befor3e building occupation to ensure healthy IAQ, which largely depends on the ventilation rates, was simulated using a simple compuer program. The results of this study can be summarized as follows: 1. In case of newly-constructed apartment houses, concentrations of formaldehyde, VOCs and radon were found to exceed the standard. Meanwhile, at existing apartment houses, concentrations of VOCs, particularly toluene and xylene, highly exceeded the standasrd level. Concentrations of formaldehyde and radon, however, had been lowered according to the duration of occupation. 2. The laboratory experiment of concentration of pollutants per square meter of building material surface area showed that radon gas was much emitted from the gypsumboard; formaldehyde from flooring and wallpaper; and VOCs from paints and kitchen furnishings. The emission rates of formaldehyde and VOCs were proportional to air temperature. 3. According to the simulation of the minimum period to be reserved before occupation, newly-constructed airtight houses required about 190-200 days, and naturally ventialted houses with fully-open-windows required about 20-45days, in order to keep the level of radon gas lower than standard. Therefore, with the current practice, the date of occupation should be delayed for about 15 days.

• Analytical Science and Technology
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• v.11 no.3
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• pp.194-201
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• 1998

The formaldehyde vapor produced from wood and steel furniture was absorbed in distilled water and derivatized with acetylacetone and determined by UV-visible spectrophotometry. Variation in HCHO emission with time was monitored at room temperature. The emission of volatile compounds from wood, wood-based and steel-based materials was investigated in a 50 mL glass vial. The concentration of the gases emitted in a glass vial was determined by ion-trap GC-MS.

• Journal of Environmental Health Sciences
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• v.45 no.5
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• pp.474-486
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• 2019

Objectives: This study was performed to investigate the emission characteristics of aldehydes emitted by the printing industry and to evaluate their impact on adjacent residential areas. Methods: Aldehydes and THC were measured from the front of the control device in the printing and coating process. Aldehydes and ketones were measured by workplace area, residential area, and background area to evaluate their impact. Results: The concentrations of formaldehyde (<0.047 ppm) and acetaldehyde (<0.068 ppm) in the printing and coating process were relatively low, and the methyl ethyl ketone used as the primary solvent was the main carbonyl compound in the printing process. The daily mean concentrations of formaldehyde and acetaldehyde were not significantly different by workplace area, residential area, or background area. However, the concentration of methyl ethyl ketone was high in the order of workplace area, residential area, and background area. Conclusions: The concentrations of formaldehyde and acetaldehyde in the adjacent residential areas are considered to be more influenced by secondary sources of photochemical reactions than by primary sources. Methyl ethyl ketone is considered to be highly influenced by the primary source, which is printing facilities.

• Journal of the Korean Wood Science and Technology
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• v.29 no.4
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• pp.33-39
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• 2001

Laboratory particleboards (PBs) were made with urea-formaldehyde (UF) resins at four press times and two resin application rates. Enclosed caul system was used for collecting the exhaust gases materials generated during the hot-pressing of PB. Exhaust gases materials generated inside the enclosed caul during the hot-pressing of PB were collected in a controlled air stream. Formaldehyde from the exhaust gases collected was determined per a chromotropic method of the National Institute of Occupational Safety and Health Method 3500. The test results showed that formaldehyde emissions during the hot-pressing of PB increased with increasing press time, UF resin mole ratio, and resin application rate.

• Journal of the Korean Wood Science and Technology
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• v.26 no.4
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• pp.50-55
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• 1998

This study was carried out to develop low density board made of rice hull which needs proper use. Urea formaldehyde adhesive(UF) was used. The raw materials were the mixtures of the rice hulls from IllFum, DongGin, ChuChong, etc. The physical and mechanical properties of rice hull insulation board were examined. The results are as follows : For the thickness of 15mm of the low density rice hull board bonded with UF resin, proper manufacturing conditions were $171^{\circ}C$ of hot pressing temperature with thickness bar for optimum density, 12 percent of resin solid contents of rice hull ovendry weight, and 20 minutes of hot pressing time. These conditions meet Korean standards(KS 3201-1982) in relation to free formaldehyde emission, bending strength, water absorption and heat resistance.