Total volatile organic compounds (TVOC) are mainly derived from indoor building materials and are one of the main causes of indoor air pollution. This paper presents a research on simulating the TVOC release of building materials in the environmental chamber. In this work, a simple and practical prediction model of exponential decay is established to study the transport and the emission behaviors under the effect of convective mass transfer theory. Based on this theory, the model considers the porous structure of indoor building materials and assumes that concentration of TVOC at the boundary of building material obeys exponential distribution. This paper focuses on two kinds of indoor building materials, interior wall coatings and wood coatings. Numerical simulation and experimental parameters are obtained by environmental chamber method. By modelling the emission of TVOCs, and comparing the present model with the classical model, the validity of the present model can be confirmed. Besides, from the results of the fitting, it can be seen that the new exponential decay predition model has a better agreement with the experimental data, and which can describe the release characteristics and transmissionmechanisms of TVOCs more accurately, and the root mean square error is much less than the classical model.

Background: To assess brain performance capacity (BPC) in relation to sleep quality, fatigue, and mental workload as evaluation indicators with explore the possible correlation with COVID-19. Methods: A cluster sampling method was adopted to randomly select 259 civil air crew members. The measurement of sleep quality, fatigue and mental workload (MWL) were assessed using Pittsburgh Sleep Quality Index (PSQI), Multidimensional Fatigue Inventory (MFI-20) and NASA Task Load Index. The impact of COVID-19 included 7 dimensions scored on a Likert scale. Canonical correlation analysis (CCA) was conducted to examine the relationship between BPC and COVID-19. Results: A total of 259 air crew members participated in the survey. Participants’ average PSQI score was 7.8 (SD = 3.8), with 49.8% reporting prevalence of insomnia, mostly of a minor degree. Participants’ MFI was an average was 56.1 (SD =10.0), with 100% reporting some incidence of fatigue, mainly severe. The weighted mental workload (MWL) score was an average of 43.1 (SD = 17.5), with reports of mostly a mid-level degree. There was a significant relationship between BPC and COVID-19, with a canonical correlation coefficient of 0.507 (P<0.001), an eigenvalue of 0.4 and a contribution rate of 69.1%. All components of BPC variable set: PSQI, MFI and MWL contributed greatly to BPC, with an absolute canonical loading of 0.8, 0.6 and 0.7, respectively; the same was true for the COVID-19 variable set, with absolute canonical loadings ranging from 0.6 to 0.95. Conclusion: CCA demonstrated that sleep, fatigue and mental workload could well evaluated BPC, and there was a medium correlation between BPC and the impact of COVID-19 in civil air crews. Trial registration: This study is registered in the Chinese Clinical Trial Registry, number ChiCTR2100053133.