Large‐scale soil application of biochar is one of the terrestrial carbon sequestration strategies for future climate change mitigation pathways, which can also help remove and sequester pollutants from contaminated soil and water. However, black carbon emissions from biochar‐amended soils can deteriorate air quality and affect human health, as the biochar particles often contain a higher amount of sorbed toxic pollutants than the soil. Yet, the extent and mechanism of inhalable particulate matter (PM₁₀) emission from biochar‐amended soils at different wind regimes have not been evaluated. Using wind tunnel experiments to simulate different wind regimes, we quantified particulate emission from sand amended with 1–4% (by weight) biochar at two size fractions: with and without <2‐mm biochar. At wind speeds below the threshold speed for soil erosion, biochar application significantly increased PM₁₀ emission by up to 400% due to the direct resuspension of inhalable biochar particles. At wind speeds above the threshold speed, emission increased by up to 300% even from biochar without inhalable fractions due to collisions of fast‐moving sand particles with large biochar particles. Using a theoretical framework, we show that particulate matter emissions from biochar‐amended soils could be higher than that previously expected at wind speeds below the erosion threshold wind speed for background soil. Our results indicate that current models for fugitive dust emissions may underestimate the particulate matter emission potential of biochar‐amended soils and will help improve the assessment of biochar emission from amended soils.

中文翻译：

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生物炭改良土壤中颗粒物的产生、再悬浮和迁移：潜在的健康风险


生物炭的大规模土壤应用是未来气候变化减缓途径的陆地碳封存策略之一，也有助于去除和封存受污染土壤和水中的污染物。然而，生物炭改良土壤中的黑碳排放会恶化空气质量并影响人类健康，因为生物炭颗粒通常比土壤含有更多量的吸附有毒污染物。然而，不同风况下生物炭改良土壤的可吸入颗粒物（PM ₁₀ ）排放的程度和机制尚未得到评估。使用风洞实验来模拟不同的风况，我们量化了用 1-4%（按重量计）生物炭修正的沙子的颗粒物排放量（按重量计），两种尺寸分数：有和没有 <2 id=56>10 排放量高达 400%，这是由于可吸入生物炭颗粒的直接再悬浮。在风速高于阈值速度时，由于快速移动的沙粒与大生物炭颗粒的碰撞，即使没有可吸入部分的生物炭，排放量也会增加高达 300%。使用理论框架，我们表明，当风速低于背景土壤的侵蚀阈值风速时，生物炭改良土壤的颗粒物排放量可能高于之前的预期。我们的结果表明，当前的扬尘排放模型可能低估了生物炭改良土壤的颗粒物排放潜力，并将有助于改进对改良土壤生物炭排放的评估。