Abstract
Emissions of hazardous organic chemicals from crumb rubber modified (CRM) asphalt mixes have been longstanding environmental and occupational health concerns. This study aimed to quantify the emissions of volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs) and total suspended particles (TSP) from CRM and polymer asphalt mixes. Occupational exposure, during paving construction activities, to particulate matter (PM) in different size was also evaluated for pavement workers by a personal exposure monitoring approach. Overall, chamber test results showed that CRM hot mix asphalt (C-HMA) emitted higher levels of VOCs and PAHs than CRM warm mix asphalt (C-WMA), whereas C-WMA emitted a higher level of TSP. Lighter PAHs dominated the emitted ∑12 PAHs in both C-HMA and C-WMA, but compositions of VOCs varied greatly between asphalt groups. The emission factors for TSP and PAHs were 110 and 2.6 μg/kg asphalt for C-HMA, and 260 and 1.3 μg/kg asphalt for C-WMA, respectively. In addition, personal exposure level of PM was overall below the exposure guideline for asphalt fumes. The results from this study are expected to contribute to a comprehensive risk assessment of using ground tyre rubber techniques in road paving industries.
•CRM asphalt in warm mix produced less emissions of PAHs and VOCs than hot mix.•Generally lower emissions of VOCs and PAHs were associated with lower temperature.•Most PAHs emitted from asphalt mixes were 3–4 rings and not carcinogenic.•The level of personal exposure of particles was below the exposure limit.