The absorption Ångström exponent (AAE) describes the spectral dependence of light absorption by aerosols. AAE is typically used to differentiate between different aerosol types for example., black carbon, brown carbon, and dust particles. In this study, the variation of AAE was investigated mainly in fresh aerosol emissions from different fuel and combustion types, including emissions from ships, buses, coal‐fired power plants, and residential wood burning. The results were assembled to provide a compendium of AAE values from different emission sources. A dual‐spot aethalometer (AE33) was used in all measurements to obtain the light absorption coefficients at seven wavelengths (370–950 nm). AAE_470/950 varied greatly between the different emission sources, ranging from −0.2 ± 0.7 to 3.0 ± 0.8. The correlation between the AAE_470/950 and AAE_370‐950 results was good (R² = 0.95) and the mean bias error between these was 0.02. In the ship engine exhaust emissions, the highest AAE_470/950 values (up to 2.0 ± 0.1) were observed when high sulfur content heavy fuel oil was used, whereas low sulfur content fuels had the lowest AAE_470/950 (0.9–1.1). In the diesel bus exhaust emissions, AAE_470/950 increased in the order of acceleration (0.8 ± 0.1), deceleration (1.1 ± 0.1), and steady driving (1.2 ± 0.1). In the coal‐fired power plant emissions, the variation of AAE_470/950 was substantial (from −0.1 ± 2.1 to 0.9 ± 1.6) due to the differences in the fuels and flue gas cleaning conditions. Fresh wood‐burning derived aerosols had AAE_470/950 from 1.1 ± 0.1 (modern masonry heater) to 1.4 ± 0.1 (pellet boiler), lower than typically associated with wood burning, while the burn cycle phase affected AAE variation.

中文翻译：

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不同排放源对气溶胶的吸收Ångström指数变化

吸收Ångström指数（AAE）描述了气溶胶吸收光的光谱依赖性。AAE通常用于区分不同的气溶胶类型，例如黑碳，棕碳和粉尘颗粒。在这项研究中，研究了AAE的变化，主要研究了不同燃料和燃烧类型产生的新鲜气溶胶排放，包括船舶，公共汽车，燃煤发电厂和民用木材燃烧产生的排放。汇总结果以提供来自不同排放源的AAE值汇总。在所有测量中均使用双点测湿仪（AE33），以获取七个波长（370–950 nm）处的光吸收系数。AAE _470/950不同排放源之间的差异很大，范围从-0.2±0.7到3.0±0.8。AAE _470/950和AAE _370-950结果之间的相关性很好（R ²  = 0.95），并且两者之间的平均偏差误差为0.02。在船用发动机废气排放中，当使用高硫含量的重质燃料油时，观察到了最高的AAE _470/950值（高达2.0±0.1），而低硫含量的燃料具有最低的AAE _470/950（0.9–1.1） 。在柴油客车废气排放中，AAE _470/950以加速（0.8±0.1），减速（1.1±0.1）和稳定行驶（1.2±0.1）的顺序增加。在燃煤电厂排放中，AAE的变化由于燃料和烟道气清洁条件的差异，_470/950相当高（从-0.1±2.1到0.9±1.6）。新鲜的木材燃烧气溶胶的AAE _470/950从1.1±0.1（现代砖石取暖器）到1.4±0.1（小丸锅炉），低于通常与木材燃烧相关的气溶胶，而燃烧循环阶段会影响AAE的变化。