## 3 Results and Discussion
\begin{table}
\begin{tabular}{p{113.8 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Material** & **Time to Reach Critical Concentration, s** & **Concentration of Combustion Products, mg/L** & **K** & **Loss of Velocity, \%** & **Ambient Temperature, \({}^{\circ}\)C** \\ \hline Plastic & 20 & 50 & 1.029 & 15 & \\ \hline Styrofoam & 11.2 & 50 & 1.035 & 20 & \\ \hline Textile & 26.2 & 50 & 1.029 & 12 & \\ \hline Gypsum plasterboard & 78.5 & 50 & 1.018 & 8 & 25 \\ \hline Wood & 32.7 & 50 & 1.03 & 25 & \\ \hline Paper & 21.8 & 50 & 1.02 & 13 & \\ \hline Motor oil & 15.7 & 50 & 1.04 & 25 & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Evaluation of the effect of combustion products from various materials on acoustic waves. Based on research in work [115], the loss of velocity (\(\Delta v\)) of acoustic waves during the passage of acoustic waves is determined according to Formula (7):  
\[\Delta v=\frac{v_{in}-v_{fin}}{v_{in}}.100\% \tag{7}\]  
where \(v_{in}\) is the velocity of sound before the release of combustion products, and \(v_{fin}\) is the velocity of sound after filling the glass flask with combustion products until reaching the limit concentration level. Specialized equations are used to determine the coefficients of the angle of incidence, absorption, temperature, and wave resistance, which take into account the influence of environmental conditions on the propagation of acoustic waves. They describe the relationship between the physical parameters of the environment and the acoustic characteristics, which then allows for the accurate adjustment of the indicators of acoustic devices. For each of the coefficients, a graphical dependence (Figure 11) was developed to provide a deep understanding of the influence of the relevant factors on the propagation of acoustic waves. The key coefficients that affect the propagation of acoustic waves are presented in Figure 11 and described below:  
(a) Acoustic waves at different angles of incidence are reflected or absorbed by surfaces with different intensities. According to [116], the correction coefficient for the angle of incidence (\(K_{\theta}\)) can be determined through the following relationship (8):  
\[K_{\theta}=\cos(\theta) \tag{8}\]  
where \(\theta\) is the angle of incidence of the wave on the obstacle, \({}^{\circ}\). As the angle of incidence of the wave on the boundary of the media increases, the value of the coefficient decreases, which indicates a decrease in the efficiency of the energy transfer. At large angles of incidence, most of the wave energy is reflected from the surface, which limits the penetration of the wave into another medium and leads to greater energy losses. Figure 11: Graphic display of the dependence of the studied coefficients: (**a**) coefficient for the angle of incidence (\(K_{\theta}\)); (**b**) absorption coefficient (\(K_{\theta}\)); (**c**) temperature coefficient (\(K_{T}\)); and (**d**) coefficient of acoustic impedance (\(Z\)) on the parameters of the environment with combustion products. (b) The concentration of suspended particles affects the coefficient of absorption and the scattering of acoustic waves (absorption coefficient, \(K_{\rho}\)). When the concentration of particles (for example, dust or combustion products) and the environment increases, the intensity of the propagation of the acoustic wave decreases, despite the increase in the number of points of interaction between the wave and particles. The effect is due to several key factors. When an acoustic wave collides with particles, part of its energy is dispersed in different directions. This reduces the amplitude of the wave in the direction of its original propagation. The energy of the acoustic wave is converted into heat or other forms of energy. Also, with a high concentration of particles in the medium, interference processes occur, in which the superimposition of waves in antiphase leads to a partial extinction of energy. This leads to an exponential decrease in the intensity of the sound signal with distance.