Extracting the Critical Points of Formaldehyde (HCHO) Emission Model in Hot Desert Climate

Abstract

Indoor air pollutants have various emission patterns and are influenced by indoor microclimate, the physical properties of building materials, and types of chemical substances. The difference in these emission patterns affects the prediction via simulation. This paper aims to extract factors that have an important influence on selecting empirical models by examining the emission pattern of formaldehyde (HCHO) from building materials. As a methodology, Small Chamber Pollutant Emission Test was used for six different flooring and wallpaper specimens, and HCHO was sampled and analyzed using HPLC (High-Performance Liquid Chromatography). The result showed that the higher the linear relationship between emission intensity and time, the more appropriate the first-order reduction model, such as flooring-A ( R2 = .99), flooring-B ( R2 = .94), wallpaper-A ( R2 = .99), and wallpaper-C ( R2 = .98). The emission pattern of HCHO in building materials is classified into three types: In type I ( R2 = .00–.11), the emission of chemical substances reaches the maximum after the start of the experiment and decreases relatively rapidly. Type II ( R2 =.00–.41), the emission pattern having the shape of a vertex with a refined concentration ascending and a gentle descending and is a type in which the suitability is significantly high in the concentration descending section, and Type III ( R2 = .33–.60), which shows a mild linear increase and decreases trend in the ascending and concentration dropping sections. It is a type that indicates the suitability with the predicted value in a meaningful way in the entire area. Even though many previous studies focused on the concentration descending section in different materials ( R2 = .51–.95), it was confirmed that the emission characteristics in the initial concentration ascending section are also critical points for simulation model selection since R2 of ascending section of Type II (.67–.70) and Type III (.77–.93) turned out statistically meaningful except Type I (.02–.25).