ABSTRACT

In this study, we investigated the association between short-term exposure to different sources of fine particulate matter (PM_2.5) and biomarkers of coagulation and inflammation in two different panels of elderly and healthy young individuals in central Tehran. Five biomarkers, including white blood cells (WBC), high sensitive C-reactive protein (hsCRP), tumor necrosis factor-soluble receptor-II (sTNF-RII), interleukin-6 (IL-6), and von Willebrand factor (vWF) were analyzed in the blood samples drawn every 8 weeks from the subjects between May 2012 and May 2013. The studied populations consisted of 44 elderly individuals at a retirement home as well as 40 young adults residing at a school dormitory. Positive Matrix Factorization (PMF)-resolved source-specific PM_2.5 mass concentrations and biomarker levels were used as the input to the linear mixed-effects regression model to evaluate the impact of exposure to previously identified PM sources at retirement home and school dormitory in two time lag configurations: lag 1–3 (1–3 days before the blood sampling), and lag 4–6 (4–6 days before the blood sampling). Our analysis of the elderly revealed positive associations of all biomarkers (except hsCRP) with particles of secondary origin in both time lags, further corroborating the toxicity of secondary aerosols formed by photochemical processing in central Tehran. Moreover, industrial emissions, and road dust particles were positively associated with WBC, sTNF-RII, and IL-6 among seniors, while vehicular emissions exhibited positive associations with all biomarkers in either first- or second-time lag. In contrast, most of the PM_2.5 sources showed insignificant associations with biomarkers of inflammation in the panel of healthy young subjects. Therefore, findings from this study indicated that various PM_2.5 sources increase the levels of inflammation and coagulation biomarkers, although the strength and significance of these associations vary depending on the type of PM sources, demographic characteristics, and differ across the different time lags.

Implications: Tehran, the capital of Iran with a population of more than 9 million people, has been facing serious air pollution challenges as a result of extensive vehicular, and industrial activities in the previous years. Among various air pollutants in Tehran, fine particulate matters (PM_2.5, particles with aerodynamic diameters < 2.5 µm) are known as one of the most important critical pollutants, causing several adverse health impacts including lung cancer, respiratory, cardiovascular, and cardiopulmonary diseases. Therefore, a number of studies in the area have tried to investigate the adverse health impacts of exposure to PM_2.5. However, no studies have ever been conducted in Tehran to examine the association between specific PM_2.5 sources and biomarkers of coagulation and systemic inflammation as indicators of cardiovascular disorders. Indeed, this is the first study in the area investigating the association of source-specific PM_2.5 with biomarkers of inflammation including white blood cells (WBC), high sensitive C-reactive protein (hsCRP), tumor necrosis factor-soluble receptor-II (sTNF-RII), interleukin-6 (IL-6), and von Willebrand factor (vWF). Our results have important implications for policy makers in identifying the most toxic sources of PM_2.5, and in turn designing schemes for mitigating adverse health impacts of air pollution in Tehran.

摘要

在这项研究中，我们在德黑兰中部的两个不同的老年人和健康年轻人小组中调查了短期暴露于不同来源的细颗粒物 (PM _2.5 ) 与凝血和炎症的生物标志物之间的关联。五种生物标志物，包括白细胞 (WBC)、高敏 C 反应蛋白 (hsCRP)、肿瘤坏死因子可溶性受体-II (sTNF-RII)、白细胞介素-6 (IL-6) 和血管性血友病因子 (vWF) ) 在 2012 年 5 月至 2013 年 5 月期间每 8 周从受试者抽取的血液样本中进行分析。研究人群包括养老院的 44 名老年人和住在学校宿舍的 40 名年轻人。正矩阵分解 (PMF) 解析的源特定 PM _2.5质量浓度和生物标志物水平被用作线性混合效应回归模型的输入，以评估在两个时间滞后配置中暴露于退休之家和学校宿舍中先前确定的 PM 源的影响：滞后 1-3（1-3 天采血前），滞后 4-6 天（采血前 4-6 天）。我们对老年人的分析显示，所有生物标志物（hsCRP 除外）在两个时滞中都与次级来源的颗粒呈正相关，进一步证实了德黑兰中部光化学处理形成的次级气溶胶的毒性。此外，工业排放和道路灰尘颗粒与老年人的 WBC、sTNF-RII 和 IL-6 呈正相关，而车辆排放与所有生物标志物在第一次或第二次滞后时呈正相关。相比之下，_2.5来源显示与健康年轻受试者小组中的炎症生物标志物无关。因此，本研究的结果表明，各种 PM _2.5来源会增加炎症和凝血生物标志物的水平，尽管这些关联的强度和意义因 PM 来源的类型、人口统计特征而异，并且在不同的时滞中有所不同。

影响: 伊朗首都德黑兰拥有超过 900 万人口，由于过去几年广泛的车辆和工业活动，一直面临着严重的空气污染挑战。在德黑兰的各种空气污染物中，细颗粒物（PM _2.5，空气动力学直径 < 2.5 µm 的颗粒）被认为是最重要的关键污染物之一，对健康造成多种不利影响，包括肺癌、呼吸系统疾病、心血管疾病和心肺疾病。因此，该地区的一些研究试图调查暴露于 PM _2.5对健康的不利影响。然而，德黑兰从未进行过任何研究来检查特定 PM _{2.5之间的关联。}凝血和全身炎症的来源和生物标志物作为心血管疾病的指标。事实上，这是该领域的第一项研究，调查特定来源 PM _2.5与炎症生物标志物之间的关系，包括白细胞 (WBC)、高敏 C 反应蛋白 (hsCRP)、肿瘤坏死因子可溶性受体 II。 sTNF-RII)、白细胞介素 6 (IL-6) 和血管性血友病因子 (vWF)。我们的研究结果对政策制定者在确定 PM _2.5毒性最强的来源方面具有重要意义，进而设计方案以减轻德黑兰空气污染对健康的不利影响。