城市工程机械尾气颗粒相多环芳烃排放特征研究-基于叉车与挖掘机的多工况案例研究

Polycyclic aromatic hydrocarbons(PAHs)are critical toxic components of PM_2.5,and accurately identifying their sources is vital for effective urban air quality improvement. However,the lack of real-world emission data for construction machinery has introduced significant uncertainties into PAHs source apportionment and emission inventories,particularly in urban areas where such machinery is widely used. Here,we characterized PAHs emissions from forklifts and excavators at construction sites in China. It is found that construction machinery,which represented by forklifts and excavators,emitted significantly higher PAHs levels compared to on-road vehicles,with average emission factors of(2435.7±977.9)μg·kg^-1 fuel for forklifts and(5098.1±376.9)μg·kg^-1 fuel for excavators. Emissions during working modes were 1.6 and 1.1 times higher than during idling for forklifts and excavators,respectively. A key finding was the dominance of four-ring PAHs(especially pyrene >50%),which contrasts sharply with the observed in diesel vehicle emissions. We believed that combining the Pyr/ (Phe+Pyr)ratio during the source apportionment using the receptor model would make it possible to separate the respective contributions of diesel vehicles and construction machinery represented by forklifts and excavators from the mobile source. Furthermore,while construction machinery accounted for less than 5% of urban vehicle numbers,it contributed over 50% of on-road vehicle PAHs emissions and approximately 20% of their toxic equivalent quotients. These results highlight the urgent need for stricter emission controls on construction machinery to reduce PAHs-related health risks in urban environments.