Effects of environmental and test conditions on VOC emissions from "wet" coating materials

Research on the Effects of Environmental Factors on the Emission of Volatile Organic Compounds from Plastic Track

The volatile organic compounds (VOCs) released from a plastic track can cause stimulation and damage to the human body; the temperature, relative humidity (RH) and air exchange rate (AER) have a significant impact on the release of VOCs from materials. In this study, we used a 0.1 m³ environmental chamber; a qualitative and quantitative analysis of VOCs released from a plastic track was conducted by gas chromatography-mass spectrometry with a temperature range of 23-60 °C, RH of 5-65% and AER of 0.5-1.5 h^-1. The formation rate, the speciation, the nature of the main compounds and the mass concentration of VOCs under different environmental conditions were determined. It is shown that with the increase of temperature, the concentration of some main VOCs gradually increased and the C_alkane and C_{oxygenated organic compounds} were larger by 736.13 μg·m^-3 and 984.22 μg·m^-3 at 60 °C, respectively. Additionally, with the increase of RH, the concentration of different VOCs gradually increased. Nonetheless, the change in RH had no effect on the concentration percentage of different VOCs in the total VOC. With the increase in AER, the concentration of different main VOCs significantly declined, as did the VOC detection rate. When the AER was increased from 0.5 h^-1 to 1.5 h^-1, the C_alkane decreased by 206.74-254.21 μg·m^-3 and C_{oxygenated organic compounds} decreased by 73.06-241.82 μg·m^-3, and the number of non-detected VOC monomers increased from 1 to 7-12 species. The conclusion is that the increase in temperature and RH can promote the emission of VOCs from a plastic track, while increasing AER significantly reduces the concentrations of VOCs. Environmental temperature mainly causes the changes in the concentrations of different VOCs, and RH is a main factor leading to the variation in the detection rate of main VOCs. Overall, the release of VOCs from a plastic track is affected by environmental temperature, AER and RH in sequence. Through this paper, we clarify the effects of ambient temperature, RH and AER on the emission of VOCs from a plastic track, and furthermore, we determine the release characteristics of plastic track VOCs.

Effects of airflow and liquid temperature on ammonia mass transfer above an emission surface: experimental study on emission rate

The present study performed a series of experiments in a wind tunnel to investigate the impact of velocity, turbulence intensity and liquid-air temperature difference on ammonia emission rates. Decreasing velocity, turbulence intensity and liquid temperature are shown to reduce the ammonia emission rates. The emission rates are more sensitive to the change of velocity at a low velocity compared to change of velocity at a higher velocity range, which corresponds with the conclusion that the boundary layer thickness of velocity increases sharply when velocity is changed from 0.2m/s to 0.1m/s. In addition, the emission rates are more sensitive to the change of temperature at a higher temperature than at a lower liquid temperature range. The influence of velocity and liquid-air temperature difference on boundary layer thickness is also analyzed. The relationship between the emission rate and boundary layer thickness is presented.