Atmospheric fine particulate matter (PM) is a critical indicator of air quality, with substantial implications for human health. Understanding the emission sources and chemical composition of PM is crucial for mitigating possible adverse health effects. This study spans five diverse cities on three continents from north and south hemisphere: Stockholm (Sweden), Kyoto (Japan), Limeira, Ribeirão Preto, and Cáceres (Brazil). Our objective was to assess PM chemical composition and regional and long-range transport influences to identify the main sources of particulate air pollution at these cities during the winter/dry seasons. All studied cities but Kyoto exhibited PM levels above World Health Organization (WHO) guidelines, with the Brazilian cities experiencing the highest fine particle pollution levels, implying increased adverse health risks. We observed significant variations in concentrations of polycyclic aromatic compounds (PACs), monosaccharide anhydrides (MAs), and inorganic elements. Limeira exhibited the highest levels of total PACs (median level of 12.4 ng m), while Cáceres displayed high variability of PACs, most likely due to episodic regional wildfire events. MA concentrations were significantly higher in Limeira and Ribeirão Preto and together with elevated levels of retene and potassium (K) they suggested a substantial influence of biomass burning. Backward air mass trajectory analysis suggested widespread Amazon and Savanna wildfires along with local fires as main contributors for these sites. All source identification approaches highlighted differences among the cities, with Stockholm and Kyoto showing influence of sources related to traffic emissions, waste burning, and long-range transport, and Brazilian cities traffic, industrial, biogenic, and more evident biomass burning. This cross-continental study provides valuable insights into PM composition and emission sources, emphasizing the impact of different emissions on air quality. Our findings underscore the importance of local strategies to mitigate air pollution and protect public health, especially in regions where PM levels consistently exceed recommended guidelines.

中文翻译：

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跨洲 PM2.5 的特征：排放和化学成分的见解

大气细颗粒物 (PM) 是空气质量的关键指标，对人类健康具有重大影响。了解 PM 的排放源和化学成分对于减轻可能的不利健康影响至关重要。这项研究跨越南北半球三大洲的五个不同城市：斯德哥尔摩（瑞典）、京都（日本）、利梅拉、里贝朗普雷图和卡塞雷斯（巴西）。我们的目标是评估 PM 化学成分以及区域和远程运输影响，以确定这些城市冬季/旱季颗粒物空气污染的主要来源。除京都外，所有研究城市的颗粒物浓度均高于世界卫生组织 (WHO) 的指导值，其中巴西城市的细颗粒物污染水平最高，这意味着不良健康风险增加。我们观察到多环芳香族化合物 (PAC)、单糖酐 (MA) 和无机元素的浓度存在显着变化。利梅拉的 PAC 总量最高（中位水平为 12.4 ng m），而卡塞雷斯的 PAC 变异性较高，这很可能是由于偶发的区域野火事件造成的。利梅拉和里贝朗普雷图的 MA 浓度显着较高，再加上 retene 和钾 (K) 水平升高，表明生物质燃烧产生了重大影响。向后气团轨迹分析表明，广泛的亚马逊和稀树草原野火以及当地火灾是这些地点的主要贡献者。所有源识别方法都突出了城市之间的差异，斯德哥尔摩和京都显示了与交通排放、废物燃烧和远程运输相关的源的影响，而巴西城市则显示了交通、工业、生物和更明显的生物质燃烧的影响。这项跨大陆研究提供了有关 PM 成分和排放源的宝贵见解，强调了不同排放对空气质量的影响。我们的研究结果强调了减轻空气污染和保护公众健康的当地战略的重要性，特别是在PM水平持续超过建议指导方针的地区。