Division of Climate and Environmental Health, Department of Air Quality and Noise, Norwegian Institute of Public Health, PO Box 222, 0213, Skøyen, Oslo, Norway.
Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology, NTNU, Trondheim, Norway.
Part Fibre Toxicol. 2022 Jul 4;19(1):45. doi: 10.1186/s12989-022-00488-5.
Traffic particulate matter (PM) comprises a mixture of particles from fuel combustion and wear of road pavement, tires and brakes. In countries with low winter temperatures the relative contribution of mineral-rich PM from road abrasion may be especially high due to use of studded tires during winter season. The aim of the present study was to sample and characterize size-fractioned PM from two road tunnels paved with different stone materials in the asphalt, and to compare the pro-inflammatory potential of these fractions in human bronchial epithelial cells (HBEC3-KT) in relation to physicochemical characteristics.
The road tunnel PM was collected with a vacuum pump and a high-volume cascade impactor sampler. PM was sampled during winter, both during humid and dry road surface conditions, and before and after cleaning the tunnels. Samples were analysed for hydrodynamic size distribution, content of elemental carbon (EC), organic carbon (OC) and endotoxin, and the capacity for acellular generation of reactive oxygen species. Cytotoxicity and pro-inflammatory responses were assessed in HBEC3-KT cells after exposure to coarse (2.5-10 μm), fine (0.18-2.5 μm) and ultrafine PM (≤ 0.18 μm), as well as particles from the respective stone materials used in the pavement.
The pro-inflammatory potency of the PM samples varied between road tunnels and size fractions, but showed more marked responses than for the stone materials used in asphalt of the respective tunnels. In particular, fine samples showed significant increases as low as 25 µg/mL (2.6 µg/cm) and were more potent than coarse samples, while ultrafine samples showed more variable responses between tunnels, sampling conditions and endpoints. The most marked responses were observed for fine PM sampled during humid road surface conditions. Linear correlation analysis showed that particle-induced cytokine responses were correlated to OC levels, while no correlations were observed for other PM characteristics.
The pro-inflammatory potential of fine road tunnel PM sampled during winter season was high compared to coarse PM. The differences between the PM-induced cytokine responses were not related to stone materials in the asphalt. However, the ratio of OC to total PM mass was associated with the pro-inflammatory potential.
交通颗粒物（PM）由燃料燃烧和道路路面、轮胎和刹车磨损产生的颗粒混合物组成。在冬季温度较低的国家，由于冬季使用钉胎，富含矿物质的 PM 可能来自道路磨损的相对贡献特别高。本研究的目的是从两条铺有不同石料的道路隧道中采集并分析分级 PM，并比较这些分级 PM 对人支气管上皮细胞（HBEC3-KT）的促炎潜力与其理化特性的关系。
使用真空泵和大容量级联冲击采样器采集道路隧道 PM。冬季在潮湿和干燥的道路表面条件下以及在隧道清洁前后采集 PM 样本。对 PM 样本进行水动力学粒径分布、元素碳 (EC)、有机碳 (OC) 和内毒素含量以及无细胞活性氧生成能力分析。暴露于粗颗粒（2.5-10μm）、细颗粒（0.18-2.5μm）和超细颗粒（≤0.18μm）以及各自隧道路面所用石料颗粒后，评估 HBEC3-KT 细胞的细胞毒性和促炎反应。
PM 样本的促炎效力在不同隧道和粒径分数之间存在差异，但比各自隧道中路面所用石料的促炎效力更显著。特别是，低至 25μg/mL（2.6μg/cm）的细颗粒样本就显示出显著增加，且比粗颗粒样本更有效，而超细颗粒样本在不同隧道、采样条件和终点之间的反应更为多变。在潮湿的道路表面条件下采样的细 PM 观察到最明显的反应。线性相关分析表明，颗粒诱导的细胞因子反应与 OC 水平相关，而与其他 PM 特征无相关性。
与粗颗粒 PM 相比，冬季采集的道路隧道细 PM 的促炎潜力较高。PM 诱导的细胞因子反应之间的差异与路面中的石料无关。然而，OC 与 PM 总质量的比值与促炎潜力相关。
