Atmospheric iron solubility varies depending on whether the particles are collected in rural or urban areas, with urban areas showing increased iron solubility. In this study, we investigate if the iron species present in different environments affects its ultimate solubility. Field data are presented from the Platte River Air Pollution and Photochemistry Experiment (PRAPPE), aimed at understanding the interactions between organic carbon and trace elements in atmospheric particulate matter (PM). 24‐hr PM_2.5 samples were collected during the summer and winter (2016–2017), at three different sites on the Eastern Colorado plains: an urban, agricultural, and a mixed site. Downtown Denver had an average total and water‐soluble iron air concentration of 181.2 and 7.7 ng m⁻³, respectively. Platteville, the mixed site, had an average of total iron of 76.1 ng m⁻³, with average water‐soluble iron concentration of 9.1 ng m⁻³. Jackson State Park (rural/agricultural) had the lowest total iron average of 31.5 ng m⁻³ and the lowest water‐soluble iron average, 1.3 ng m⁻³. The iron oxidation state and chemical speciation of 97 samples across all sites and seasons was probed by X‐ray absorption near edge structure (XANES) spectroscopy. The most common iron phases observed were almandine (Fe₃Al₂Si₃O₁₂) (Denver 21%, Platteville 16%, Jackson 24%), magnetite (Fe₃O₄) (Denver 9%, Platteville 4%, Jackson 5%) and Fe (III)dextran (Denver 5%, Platteville 13%, Jackson 5%), a surrogate for Fe‐organic complexes. Additionally, native iron [Fe(0)] was found in significant amounts at all sites. No correlation was observed between iron solubility and iron oxidation state or chemical speciation.

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美国科罗拉多州城市，农业和混合环境中PM2.5中的铁形态

大气中铁的溶解度取决于颗粒是在农村地区还是城市地区收集的，而城市地区的铁溶解度增加。在这项研究中，我们调查了存在于不同环境中的铁物种是否会影响其最终溶解度。实地数据来自普拉特河空气污染和光化学实验（PRAPPE），旨在了解有机碳与大气颗粒物（PM）中微量元素之间的相互作用。在夏季和冬季（2016-2017年），在科罗拉多州东部平原的三个不同地点（城市，农业和混合地点）收集了24小时PM _2.5样品。丹佛市中心的总铁和水溶性铁的平均空气浓度为181.2和7.7 ng m ^-3， 分别。混合地点普拉特维尔的平均总铁含量为76.1 ng m ^-3，平均水溶性铁浓度为9.1 ng m ^-3。杰克逊州立公园（农村/农业）的总铁平均值最低，为31.5 ng m ^-3，而水溶性铁平均值最低，为1.3 ng m ^-3。通过X射线吸收近边缘结构（XANES）光谱探测了所有地点和季节的97个样品的铁氧化态和化学形态。观察到的最常见的铁相是铝金刚烷（Fe ₃ Al 2 Si ₃ O 12）（丹佛21％，普拉特维尔16％，杰克逊24％），磁铁矿（Fe ₃ O ₄）（丹佛9％，普拉特维尔4％，杰克逊5％）和铁（III）葡聚糖（丹佛5％，普拉特维尔13％，杰克逊5％），是铁有机配合物的替代物。此外，在所有位置都发现了大量的天然铁[Fe（0）]。在铁的溶解度与铁的氧化态或化学形态之间未发现相关性。