Previous studies in Addis Ababa, Ethiopia, focused on PM characteristics and sources, but PM's biological activity in this area has not been adequately investigated. In this study, cellular and acellular ROS activities were measured to assess PM toxicity. PM_2.5 samples in Addis Ababa were collected from November 2015 to November 2016 and their chemical composition was analyzed (organic and elemental carbon (OC/EC), ions, elements, and organic molecular markers). PM-induced ROS activity was measured in vitro in alveolar macrophage cells and using the acellular DTT assay. PM_2.5 in Addis Ababa primarily consisted of primary pollutants (e.g., EC, water-insoluble OC). Annual average cellular ROS activities (±SD) were 46.5 ± 15.5 μg Zymosan/m³ and 995 ± 403 μg Zymosan/mg PM (normalized to air volume and PM_2.5 mass, respectively), with no clear seasonal variations. The annual average DTT consumption rates (±SD) were 2.35 ± 0.83 nmol/min/m³ and 51.9 ± 17.6 nmol/min/mg PM, respectively, and were also similar throughout the year. Only the monthly air volume-based ROS activity had a similar trend to monthly mass concentration. Compared to other major cities worldwide, Addis Ababa PM_2.5 had much lower ROS activity with no strong seasonal trends, paralleling the lack of seasonal changes in PM composition and sources. Poor correlations were observed between ROS activity and all components except mobile source tracers. This difference might be due to lower secondary aerosol content in PM_2.5 in Addis Ababa than in other cities.

此前在埃塞俄比亚亚的斯亚贝巴开展的研究侧重于 PM 的特征和来源，但尚未充分研究 PM 在该领域的生物活性。在这项研究中，测量了细胞和非细胞 ROS 活性以评估 PM 毒性。亚的斯亚贝巴PM _2.5样本于 2015 年 11 月至 2016 年 11 月收集，并分析了其化学成分（有机和元素碳 (OC/EC)、离子、元素和有机分子标记）。PM 诱导的 ROS 活性在体外在肺泡巨噬细胞中测量并使用无细胞 DTT 测定。亚的斯亚贝巴的PM _2.5主要由初级污染物（例如，EC、水不溶性有机碳）组成。年平均细胞 ROS 活性 (±SD) 为 46.5 ± 15.5 μg Zymosan/m ³和 995 ± 403 μg Zymosan/mg PM（分别标准化为空气体积和 PM _2.5质量），没有明显的季节性变化。年平均 DTT 消耗率 (±SD) 分别为 2.35 ± 0.83 nmol/min/m ³和 51.9 ± 17.6 nmol/min/mg PM，全年也相似。只有每月基于空气量的 ROS 活动与每月质量浓度具有相似的趋势。与全球其他主要城市相比，亚的斯亚贝巴 PM _{2.5 的}ROS 活动要低得多，没有强烈的季节性趋势，同时 PM 成分和来源缺乏季节性变化。在 ROS 活动和除移动源示踪剂之外的所有组件之间观察到较差的相关性。这种差异可能是由于 PM _{2.5 中}次级气溶胶含量较低 亚的斯亚贝巴比其他城市多。