Screening and environmental risk assessment of VOCs preferential pollutants in net flavor rubber-modified asphalt based on the information entropy method

The problem of high viscosity during construction of rubber-modified asphalt (RMA) will lead to more energy consumption and harmful odor emissions. A powder-based net flavor agent (NFA) was applied to manage the emission of volatile organic compounds (VOCs) in RMA to investigate the inhibition of asphalt VOCs and odor purification mechanism. The relationship between odor description, olfactory threshold and molecular structure of malodor-controlled substances in VOCs was sorted out. The environmental impact assessment of RMA was evaluated using multiple indicators, and the screening list of superior control species was determined by weighting the indicators using the information entropy method. The results were indicated that NFA could reduce the total concentration of asphalt VOCs from 845.93 mg/m3 to 197.96 mg/m3, with a reduction rate of 76.6%. The presence of NFA was caused a dramatic decrease in the concentration of malodor-controlled substances, thus reducing its environmental hazards. The effect of NFA had resulted in a significant reduction in the types and concentrations of carcinogens. The cumulative non-carcinogenic risk was reduced to near the safety threshold by 72.25%, and the cumulative carcinogenic risk was reduced by 87.47%. Primary control pollutants were benzene, toluene, hydrogen sulfide, dimethyl disulfide, trichloroethylene and styrene. Sulfides were required focused control since they had a critically low olfactory threshold and were highly offensive to the human olfactory organs.