Department of Environmental Studies, Keene State College, Keene, NH, 03431, United States.
Department of Earth Sciences, University of New Hampshire, Durham, NH 03824, United States.
Sci Total Environ. 2017 May 15;586:409-418. doi: 10.1016/j.scitotenv.2016.12.041. Epub 2017 Feb 21.
Biodiesel is regarded by many as a "greener" alternative fuel to petroleum diesel with potentially lower health risk. However, recent studies examining biodiesel particulate matter (PM) characteristics and health effects are contradictive, and typically utilize PM generated by passenger car engines in laboratory settings. There is a critical need to analyze diesel and biodiesel PM generated in a "real-world" setting where heavy duty-diesel (HDD) engines and commercially purchased fuel are utilized. This study compares the mass concentrations, chemical composition and cytotoxicity of real-world PM from combustion of both petroleum diesel and a waste grease 20% biodiesel blend (B20) at a community recycling center operating HDD nonroad equipment. PM was analyzed for metals, elemental/organic carbon (EC/OC), polycyclic aromatic hydrocarbons (PAHs), and nitro-polycyclic aromatic hydrocarbons (N-PAHs). Cytotoxicity in a human lung epithelial cell line (BEAS-2B) following 24h exposure to the real-world particles was also evaluated. On average, higher concentrations for both EC and OC were measured in diesel PM. B20 PM contained significantly higher levels of Cu and Mo whereas diesel PM contained significantly higher concentrations of Pb. Principal component analysis determined Mo, Cu, and Ni were the metals with the greatest loading factor, suggesting a unique pattern related to the B20 fuel source. Total PAH concentration during diesel fuel use was 1.9 times higher than during B20 operations; however, total N-PAH concentration was 3.3 times higher during B20 use. Diesel PM cytotoxicity was 8.5 times higher than B20 PM (p<0.05) in a BEAS-2B cell line. This study contributes novel data on real-world, nonroad engine sources of metals, PAH and N-PAH species, comparing tailpipe PM vs. PM collected inside the equipment cabin. Results suggest PM generated from burning petroleum diesel in nonroad engines may be more harmful to human health, but the links between exposure, composition and toxicity are not straightforward.
生物柴油被许多人认为是一种比石油柴油更“环保”的替代燃料，潜在的健康风险可能更低。然而，最近研究生物柴油颗粒物（PM）特征和健康影响的研究结果相互矛盾，并且通常在实验室环境中利用乘用车发动机产生的 PM。因此，迫切需要分析在使用重型柴油机（HDD）发动机和商业购买燃料的“真实世界”环境中产生的柴油和生物柴油 PM。本研究比较了在社区回收中心燃烧石油柴油和 20%废油脂生物柴油混合物（B20）的 HDD 非道路设备时，来自实际 PM 的质量浓度、化学成分和细胞毒性。对 PM 中的金属、元素/有机碳（EC/OC）、多环芳烃（PAHs）和硝基多环芳烃（N-PAHs）进行了分析。还评估了暴露于实际颗粒物 24 小时后对人肺上皮细胞系（BEAS-2B）的细胞毒性。平均而言，在柴油 PM 中测量到的 EC 和 OC 浓度更高。B20 PM 中 Cu 和 Mo 的含量明显较高，而柴油 PM 中 Pb 的浓度明显较高。主成分分析确定 Mo、Cu 和 Ni 是具有最大加载因子的金属，这表明与 B20 燃料来源有关的独特模式。在使用柴油燃料时，总 PAH 浓度是使用 B20 时的 1.9 倍；然而，在使用 B20 时，总 N-PAH 浓度是使用 B20 时的 3.3 倍。在 BEAS-2B 细胞系中，柴油 PM 的细胞毒性比 B20 PM 高 8.5 倍（p<0.05）。本研究提供了有关比较排气管 PM 与设备机舱内收集的 PM 时，非道路发动机来源的金属、PAH 和 N-PAH 物种的新数据。结果表明，在非道路发动机中燃烧石油柴油产生的 PM 可能对人类健康更有害，但暴露、组成和毒性之间的联系并不简单。
