ارزیابی ضرایب تاثیر بر روی انتشار VOC و همچنین غلظت از کف پوش های چوبی بر اساس آزمایش های محفظه ای

In this study, the impact factors of temperature, relative humidity (RH), air exchange rate, and volatile organic compound (VOC) properties on the VOC (toluene, n-butyl acetate, ethylbenzene, and m,p-xylene) specific emission rates (SERs) and concentrations from wooden flooring were investigated by chamber test for 8 days. The tested wood in this study is not common solid wood, but composite wood made of combined wood fibers. The experiments were conducted in a stainless-steel environmental test chamber coated with Teflon. The experimental results within 8 days of testing showed that, when the temperature increased from 15 to 30 °C, the VOC SERs and concentrations increased 1.5–129 times. When the RH increased from 50% to 80%, the VOC concentrations and SERs increased 1–32 times. When the air change rate increased from 1 to 2 h−1, the VOC concentrations decreased 9–40%, while the VOC SERs increased 6–98%. The relations between the boiling points of the VOCs and each of the normalized VOC SERs and concentrations were linear with negative slopes. The relations between the vapor pressures of the VOCs and each of the normalized VOC SERs and concentrations were linear with positive slopes. At 15 °C, RH50%, the relations between the diffusivities of VOCs and each of the normalized VOC equilibrium SERs and concentrations were linear with a positive slope.

The volatile organic compounds (VOCs) emitted from building materials have been recognized as pollutants that may deteriorate indoor air quality in terms of odor annoyance, and eye and airway irritation, which may be related to the sick building syndrome [1], [2], [3], [4] and [5]. Some studies have shown that air temperature and humidity have a strong impact on the perception of air quality or VOC emissions from building materials [4], [6], [7], [8] and [9]. Wolkoff [4] and [7] measured the time course emissions of VOCs from five building materials (carpet, PVC flooring, sealant, waterborne wall paint, and floor varnish). After ventilation of the materials for 1 week, most of the VOC emissions increased when the temperature increased. Increasing the relative humidity (RH) by 50% was seen to increase the emission of VOCs emitted from carpet, sealant, and wall paint. However, after being ventilated for 3 weeks, most of the VOC emissions from the materials were independent of air temperature and humidity. Overall, the effect of temperature and RH depended strongly on the type of building products and type of VOCs. A strong impact of temperature and humidity on the emission of formaldehyde from chipboard was observed by Andersen et al. [9]. They found that within the temperature range 14–35 °C, the chemical emission rate of formaldehyde was doubled for each 7 °C temperature rise. Also, the emission rate was doubled when the relative air humidity increased from 30% to 70% at 22 °C. Sollinger et al. [10] studied the impact of temperature and humidity on the VOC emission from textile floor coverings by determining equilibrium concentrations (zero air change) at elevated temperatures in the range 23–71 °C and at a RH of 0% and 45%. They found that emission of the relative volatile compounds such as styrene showed little dependence on temperature. Strong temperature dependence was found for the emission of low-volatility compounds such as benzothiazol. However, the emission of all VOCs identified in the experiment was found to be independent of temperature in the typical indoor temperature range 23–30 °C. The effect of RH on VOC emission from the carpet tested was found to be negligible, expect for aniline. Air velocity impact of VOC emission was also studied by some researchers. Wolkoff [7] showed that primary source emissions were not affected by air velocity after a few days to a large extent. The primary VOC emissions from most building products were shown to be independent of air velocity, while increased air velocity may result in increased secondary VOC emissions if the building product surface is sensitive to oxidative degradation [11]. The objective of this study is to investigate the effects of temperature, RH, and air change rate on the VOC specific emission rates (SERs) and concentrations from wooden flooring, one of the common building materials for interior decoration. The relations between the VOC SERs and concentrations and the properties of VOCs were also studied. The VOC emission experiments were conducted in an environmental test chamber. The double-exponential model developed by Colombo et al. [12] was selectively picked to fit the observed VOC concentration–time profiles. The results could be used to predict VOC SERs and concentrations and evaluate the occupant exposure to VOCs.

In this study, we demonstrated the effect of temperature, RH, and air exchange rate on the concentration–time profile of VOC SERs from wooden flooring through a 8-day chamber test. The wood tested in this study is not common solid wood, but composite wood made of combined wood fibers. Increase of temperature and RH had a positive effect on VOC SERs and concentrations. The enhancement effect of air exchange rate on the VOC SERs was significantly weaker than that of temperature and RH. However, the results are in strong disagreement with a number of previous studies about the influence of air exchange rate, and this needs further research to understand this discrepancy. In addition, type of VOC emissions, e.g. VOC properties, such as boiling point, vapor pressure, and diffusivities, also had similar strong effects on VOC SERs and correlated relations may be used to predict whether specific VOCs and what species of VOCs would be emitted. This study provides a rather detailed characterization about how exactly these factors would affect VOC SERs and is in a good agreement with peer-reviewed literatures. The result might be also applied to evaluate the occupant exposure to VOCs.