Study On The Key Factors Affecting The Volatile Organic Compounds(VOCs) Emission From A Furniture Lacquer

Low-quality building materials emit a large amount of volatile organic compounds(VOCs),which is the main reason for the underground air quality in the building.Indoor building materials can be roughly divided into 'wet' building materials and 'dry' building materials.The detection of VOCs emission of these building materials is generally conducted under constant conditions(eg,25?,50%,1h-1).But in reality,environmental temperature,humidity,and the amount of materials used are not fixed and will change with the environment or human behavior.Therefore,it is of great significance to study the influence of these factors on the material emission characteristics.In this paper,polyurethane wood furniture paint is used as a typical wet material.The concentration-time data for the wood lacquer under different conditions were obtained using the environmental chamber test method,and the curves were fitted using a double-exponential empirical model.To study the effects of temperature,humidity,and thickness on the emission of contaminants from wet materials.The environmental conditions in this paper are:three temperature conditions of 15?,25?,and 35?;three relative humidity conditions of 30%,50%,and 80%;and three dose conditions of 143g/m2,286g/m2.and 429g/m2.Taking the limits of formaldehyde,benzene,toluene,xylene,and total volatile organic compounds(TVOC)as stipulated in China's Indoor Air Quality Standard,the specific experimental and theoretical analysis results are as follows.(1)Different operating conditions show similar trends.During the initial drying stage of the furniture wood lacquer,the contaminants emanate strongly and then decay rapidly.Discharged into the equilibrium phase after a certain period of time,the concentration of pollutants in the chamber gradually stabilized.Among the pollutants studied here,the concentration of xylene is the highest.Temperature,relative humidity,and thickness have a great influence on the change of pollutant concentrations,on the change of each pollutant types,and on the double exponential model fitting parameters.The effect of temperature and thickness on the emission of pollutants is more pronounced.The influence of relative humidity on the basis of this study is difficult to generalize.The concentration and the proportion of aromatic hydrocarbons in different working conditions range mostly 80-90%.The concentration of each pollutant category is not exactly the same as that of TVOC.(2)The peak concentration of each pollutant has an increase of approximately 5-15 times under the promotion of temperature.Different temperature changes have different effects on emission.In the range of 15?-25?,the concentration of pollutants increases obviously;in the range of 25?-35?,the difference of peak concentration is relatively small.The influence of relative humidity is more complicated.The overall curve of most pollutants is 50%,30%,and 80%from high to low.Except for formaldehyde,the peak concentration of other pollutants changes little with the relative humidity,and the concentration in the equilibrium phase is greatly influenced by the humidity.The thicker the wet material,the greater the emission of contaminants.The initial changes of formaldehyde and benzene concentrations were greatly influenced by the thickness,and the influence decreased in the later period.The pollutants are classified into aromatic hydrocarbons,ketone aldehyde esters,alkanes and other types.The higher the temperature is,the greater the proportion of each concentration decreases.There is no obvious regularity in the effect of relative humidity on different types of pollutants.When the humidity is 50%,the peak concentration and the equilibrium concentration of the ketoaldehyde ester are both high.The concentration of the alkanes and other species is low,and decreased greatly with time under different humidity conditions.The concentration of different contaminant species rises over thickness.Only the concentration of the alkane in the 286 g/m2 stabilization phase was higher than that at the peak time.(3)The pollutant concentration change curve fitted by the double exponential empirical model for each operating condition corresponds to the four parameters E1,E2,k1,and k2,respectively.The change with the three influencing factors is consistent with the change of pollutant concentration.The same pollutant in wooden paint has different sensitivity to different influencing factors.The k1 and k2 values of formaldehyde were the smallest at all temperatures,which corresponded to the longest time required for formaldehyde to decay from peak to stable concentration and the slowest decay of emission over time.The k2 of formaldehyde and benzene is most affected by humidity,and the value increases 10-15 times when the relative humidity is 50%.The k1 and k2 of benzene are most affected by the thickness.In summary,this article believes that protective measures should be strengthened during the brushing process of wet materials,and the temperature can be appropriately increased to promote the emission of contaminants in the material.The thickness of the wet material should not be too large during use.The substrate should be kept as flat as possible to minimize the use of paint.