Parent and methyl polycyclic aromatic hydrocarbons and n-alkanes emitted by construction machinery in China

Abstract Construction machinery emits considerable quantities of organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and n-alkanes, which significantly affect air quality, human health, and climate change. However, actions to reduce the pollution caused by these pollutants are insufficient due to a lack of comprehensive studies. Therefore, 16 United States Environmental Protection Agency (EPA) priority control PAHs (pPAHs), nine methyl PAHs (mPAHs), and 27 n-alkanes (C12-C38) in particulate matter (PM2.5) emitted by 20 construction machines of different types and emission standards, operated under three modes, were measured in this study. The results showed that (1) the total fuel-based emission factors of pPAHs, mPAHs, and n-alkanes for construction machinery were in the ranges 0.033-1.43, 0.027-1.37, and 1.32-87 mg/kg fuel, respectively. (2) The average emission factors of pPAHs, mPAHs, and n-alkanes in excavator and bulldozer emissions were higher than those in loader and forklift emissions, which can be attributed to machine type, operation mode, emission standards, and engine power. (3) Pry, Phe, C18-C22, 1-mNaP, and mFluo emissions were significantly dominant. Some diagnostic ratios of PAHs (e.g., Ant/(Ant+Phe), Flu/(Flu+Pry), BaA/(BaA+Chry), and IP/(IP+BghiP)) were consistent with those emitted by liquid fossil fuel combustion, whereas the ratios of low molecular weight n-alkanes (C ≤ 24) to high molecular weight (C > 24) n-alkanes from construction machines were higher than those for on-road gasoline vehicles, diesel vehicles, and vessels. (4) The benzo(a)pyrene equivalents (BaPeq) and lifetime cancer risk (LCR) values of PAHs from bulldozer and forklift emissions were higher than those from excavator and loader emissions, especially under working modes. Furthermore, the BaPeq and LCR values of PAHs from construction machineries were higher than that specified by GB3095-2012 and 10^-4, respectively, thereby indicating that PAHs emitted from construction machines pose high health risks.