Study On The Emission Behavior Of Volatile Organic Compounds (VOCs) In The Interior Wall Coating And Paint

Objective (1) To understand the indoor pollution conditions of Volatile Organic Compounds (VOCs) and formaldehyde in the restaurants in Lanzhou. (2) To study the status of VOCs in two kinds of interior wall coating best selling, totally 25 brands. (3) To explore the emission behaviors of VOCs releasing from interior wall coating and oil paint under different experimental conditions.Methods (1) Two restaurants decorated with different materials were chosen to determine indoor concentrations of VOCs and formaldehyde. VOCs and formaldehyde were detected by ToxiRAE PGM-30 and acetylacetone spectrophotometric method, respectively. (2) VOCs, density and the water in two kinds of interior wall coating were tested by GB6751-86, GB6750-86 and azeotropic distillation, respectively. (3) Experimental studies were carried out to explore the emission of VOCs from interior wall coating and oil paint in a laboratory chamber, then the results were analyzed by medical statistical software.Results (1) The significant differences in concentrations of VOCs and formaldehyde were found between two restaurants. Meanwhile, the human activities could make 30 percent contribution to the indoor VOCs concentration. Moreover, the concentration of VOCs in the restaurant using air fresher was six times higher than that without air fresher. Furthermore, the concentration of VOCs was positively related to the indoor temperature and relative humidity in a reasonable range. (2) With regard to the quantities of VOCs, 42% of the tested water soluble coating (5 out of 12 samples) and 23% of the tested emulsion (3 out of 13 samples) were above 200g/L evaluated by GB18582-2001. No significantly statistical differencebetween the two kinds of interior wall coating was found (t=\.657 P>0.05 ). (3) The mathematical model of VOCs emission from interior wall coating and paint was proposed;The emission coefficient which could determine the emission behavior of VOCs from those materials was defined;The mechanism and the rate-controlling step of VOCs emission from those materials were analyzed;Meanwhile, the effect of temperature, ratio loading, film thickness, air exchange rate and relative humidity on VOCs emission from those materials were discussed, respectively. In a reasonable range, the concentration and diffusion flux of VOCs in the laboratory chamber increased with the rise in temperature, ratio loading, film thickness and relative humidity, respectively. Furthermore, the quantity of the VOCs in interior wall coating and paint decreased with the increase in air exchange rate. Finally, under people's living condition, the VOCs concentration varied with time in a laboratory chamber followed the hyperbolic logarithm.Conclusions ? The indoor pollutions of VOCs and formaldehyde are closely related to the decorative materials. Moreover, human activities, air fresher, indoor temperature and relative humidity are some important factors affecting indoor concentrations of VOCs and formaldehyde. (2) The results show that the quality of the two kinds of interior wall coating is much concerned, therefore, the government should pay more attentions to quality and health safety of interior wall coating. (3) The proposed mathematical model can describe the mass thansfer behavior of VOCs from materials well and analyze the rate-controlling step accurately. Furthermore, it can also interpret the effect of those factors on the emission behavior. Furthermore, those environmental factors can dramatically influence the emission of VOCs from materials, thus it implies that the indoor pollution of VOCs can be expected to be controlled by optimizing those factors for dweller's health.