Main components and emission characteristics of environmentally hazardous substances from road asphalt

Road asphalt produces hazardous substances that pollute the environment and significantly endanger human health. To clarify complex emission characteristics of these asphalt hazardous substances (AHS), their main components of AHS were comprehensively investigated and summarized. Furthermore, the emission rules of AHS under different testing conditions were systematically studied. To quantify these dynamics, robust regression models between AHS emissions and various experimental variable were successfully established. The analytical results demonstrated that the fundamental components of AHS mainly include volatile organic compounds, inorganic small molecule gases, and solid particles. Regarding thermodynamic variables, AHS emissions exhibit a marked increase as heating temperatures elevate. This specific dynamic conforms accurately to a power function relationship, yielding a strong correlation coefficient of 0.98. Conversely, AHS emissions progressively decrease with increasing heating times; this relationship conforms to an exponential function, demonstrating a correlation coefficient of 0.90. Additionally, the increased multiples of AHS emissions and asphalt qualities conform to a positive linear functional relationship, supported by a correlation coefficient of 0.96. A comparative analysis revealed that AHS emissions originating from rubber powder-modified asphalt are the highest. In stark contrast, AHS emissions from styrene-butadiene-styrene asphalt are notably the lowest when compared directly to the other three types of commonly used road asphalt. The emitted asphalt hazardous gases generate secondary inorganic salts and secondary aerosols, which actively promote the subsequent formation of fine particulate matter within these highly complex aerosol systems.