The oxidative potential of PM2.5 is investigated for the first time in Bhubaneswar using dithiothreitol (DTT) assay, an urban coastal city in eastern India. PM2.5 samples were collected for four years during summertime and analyzed for metals, water-soluble ions, black carbon, and brown carbon. Overall mean PM2.5 mass concentration was 31.93 ± 14.91 μg m−3, in which (NH4)2SO4 (44%) was the dominant species. The analysis employing the Conditional Bivariate Probability Function indicates that PM2.5 mass concentration in the summer season is predominantly influenced by transport facilitated by south-southwest and southeast winds. The primary origin is identified as non-buoyant local sources. The volume-normalized and mass-normalized DTT followed the same trend as PM2.5 mass concentration. No significant inter-year variation in DTT activity indicated a potential constancy in the source strength during the study period. The observed DTTv (0.48 ± 0.30 nmol min−1 m−3) and DTTm (15.36 ± 7.67 pmol min−1 μg−1) were comparatively lower than those reported in most other locations in India. Multiple linear regression analysis suggested that Cu (34%) and Zn (32%) were dominant contributors to DTTv activity. However, further studies are required for a comprehensive understanding of PM2.5 toxicity.

中文翻译：

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印度东海岸城市夏季 PM2.5 的化学特征和氧化潜力


在印度东部沿海城市布巴内斯瓦尔，首次使用二硫苏糖醇 (DTT) 测定法研究了 PM2.5 的氧化潜力。我们在四年的夏季收集了 PM2.5 样本，并分析了金属、水溶性离子、黑碳和棕碳。 PM2.5 总体平均质量浓度为 31.93 ± 14.91 μg m−3，其中 (NH4)2SO4 (44%) 为主要成分。采用条件双变量概率函数的分析表明，夏季 PM2.5 质量浓度主要受西南风和东南风促进的输送的影响。主要来源被确定为非浮力当地来源。体积归一化和质量归一化 DTT 遵循与 PM2.5 质量浓度相同的趋势。 DTT 活动没有显着的年际变化表明研究期间源强度可能保持恒定。观察到的 DTTv（0.48 ± 0.30 nmol min−1 m−3）和 DTTm（15.36 ± 7.67 pmol min−1 μg−1）相对低于印度大多数其他地点报告的值。多元线性回归分析表明，Cu (34%) 和 Zn (32%) 是 DTTv 活动的主要贡献者。然而，还需要进一步的研究来全面了解 PM2.5 的毒性。