# Analysis of the Odor Purification Mechanism and Smoke Release of Warm-Mixed Rubber Asphalt
## 3 Results and Discussion
### Analysis of Asphalt Smoke Composition
#### 3.5.4 Hydrogen Sulfide  
As shown in Figure 8a, there are differences in the degradation efficiency of hydrogen sulfide among the three types of asphalt, namely matrix asphalt NA, rubber asphalt AR, and warm-mix rubber asphalt WMAR. The hydrogen sulfide concentrations generated by the three types of asphalt during the experimental process are 0.153 mg/m\({}^{3}\), 0.194 mg/m\({}^{3}\), and 0.177 mg/m\({}^{3}\), respectively. Among them, the matrix asphalt has the most significant degradation effect on hydrogen sulfide, indicating that during the process of asphalt modification, the degradation degree of modified asphalt on hydrogen sulfide has de creased. During the process of asphalt modification, rubber asphalt AR and warm-mix pure-odor asphalt WMAR contain higher levels of VOCs, so more harmful gases are emitted during heating, and the degradation degree of nitrogen oxides by modified asphalt is reduced. When adding new materials or warm-mix agents, modified asphalt may undergo chemical reactions, which may lead to an increase in the content of VOCs in the asphalt. The experiment was conducted by adding rubber asphalt AR and warm-mix clean odor asphalt WMAR to liquid and powder deodorizers with proposed concentrations of 0%, 0.2%, 0.4%, and 0.6%. The experimental results showed that the modified asphalt with deodorizers reduced the concentration of hydrogen sulfide produced to varying degrees in the experiment, and the degradation effect was better.  
In Figure 7(b), it can be seen that for liquid deodorant (LD), when the proposed deodorant dosage is 0%, 0.2%, 0.4%, and 0.6%, the hydrogen sulfide concentration generated by the purified rubber asphalt DAR in the experiment is 0.194 mg/m\({}^{3}\), 0.142 mg/m\({}^{3}\), 0.123 mg/m\({}^{3}\), and 0.11 mg/m\({}^{3}\), respectively. The degradation rate is 43.2%. The hydrogen sulfide concentrations generated by DWMAR, a clean and warm-mixed rubber asphalt, in the experiment are 0.177 mg/m\({}^{3}\), 0.114 mg/m\({}^{3}\), 0.107 mg/m\({}^{3}\), and 0.095 mg/m\({}^{3}\) respec  
Figure 7: Sulfur dioxide analysis.  
tively. The degradation rate is 46.3%. For PD odor remover, when the proposed dosage of odor remover is 0%, 0.2%, 0.4%, and 0.6%, the hydrogen sulfide concentration generated by DAR in the experiment is 0.194 mg/m\({}^{3}\), 0.133 mg/m\({}^{3}\), 0.119 mg/m\({}^{3}\), and 0.107 mg/m\({}^{3}\), respectively. The degradation rate is 44.8%. The hydrogen sulfide concentrations generated by DWMAR, a clean and warm-mixed rubber asphalt, in the experiment are 0.177 mg/m\({}^{3}\), 0.099 mg/m\({}^{3}\), 0.086 mg/m\({}^{3}\), and 0.078 mg/m\({}^{3}\), respectively. The degradation rate is 55.9%, indicating that for the same type of deodorizer, an increase in the dosage of the deodorizer results in a decrease in the concentration of hydrogen sulfide and sulfur dioxide, and a better degradation effect. When adding the same type and concentration of odor clarifying agents, the degradation rate of hydrogen sulfide in DWMAR is higher, indicating that the coupling effect of temperature mixing agents and odor-purifying agents may increase the degradation rate of hydrogen sulfide. In addition, the line chart shows that adding the same concentration of odor remover to the same type of asphalt results in a better degradation effect when powder odor remover is added.