Abstract. Black Carbon (BC) is a component of particulate matter, emitted from the incomplete combustion of carbonaceous fuels. The presence of BC in the atmosphere can disrupt the atmospheric radiation budget, and exposure to BC can adversely affect human health. Multi-wavelength light absorption-based dual-spot aethalometers can be used to quantify the source and characteristics of BC from traffic or biomass burning-based sources. However, aethalometer measurements are affected by artifacts such as aerosol loading and light scattering; hence, they often need correction to reduce measurement uncertainty. This work assesses the performance of the recently developed portable aethalometer (MA300, AethLabs). Due to their portability and ease of usage, MA300s can be suitable for mobile and personal exposure monitoring. Here, we evaluate BC concentration and source apportionment accuracy of three MA300 units relative to a widely used aethalometer, the AE33 (Magee Scientific). Synchronous field measurements were performed at a major traffic intersection during regular and wildfire smoke-affected days in Vancouver, Canada. We find that MA300 reported BC mass concentrations were strongly correlated (Slope range between 0.73 and 1.01, with R² = 0.9) compared to the reference instrument, yet there is visible instrumental variability (15 %) across three units. The mean absolute error of MA300 reported BC concentrations ranged between 0.44–0.98 ug m^-3 with the highest deviations observed in wildfire smoke-affected polluted days. From the aerosol light absorption measurement perspective, MA300s tend to underestimate the absorption coefficients (b_abs) across the five wavelengths. UV channel light absorption results were subjected to the highest amount of noise, leading to systematic bias in source apportionment analysis. We investigated the application of the latest non-linear aethalometer correction protocols in the MA300 and found that flow fluctuations enhanced noise across all channels, compared to onboard instrument correction. We also identify that the UV (λ = 370 nm) channel absorption measurements are most sensitive to instrumental artifacts during the wildfire smoke-affected period. Hence, as an alternative to traditional UV and IR (λ = 880 nm)-based BC source apportionment methods, in this work, we tested the Blue (λ = 470 nm) and IR wavelengths for BC source apportionment calculation. By adopting Blue-IR based source apportionment technique in MA300, the apportioned BC components improves on average in the order of 10 % when compared against the reference monitor's results.

中文翻译：

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用于黑碳气溶胶来源识别的便携式双点微型空气量计的性能评估：在太平洋西北地区的野火烟雾和交通排放中的应用

摘要。黑碳 (BC) 是颗粒物质的一种成分，由含碳燃料的不完全燃烧排放。大气中 BC 的存在会破坏大气辐射收支，接触 BC 会对人类健康产生不利影响。基于多波长光吸收的双点测速仪可用于量化来自交通或生物质燃烧来源的 BC 的来源和特征。但是，气溶胶测量会受到气溶胶负载和光散射等伪影的影响；因此，它们通常需要校正以减少测量不确定性。这项工作评估了最近开发的便携式 aethalometer (MA300, AethLabs) 的性能。由于其便携性和易用性，MA300 可适用于移动和个人暴露监测。这里，我们评估了三个 MA300 装置相对于广泛使用的 AE33（Magee Scientific）的 BC 浓度和源分配精度。在加拿大温哥华的常规和受野火烟雾影响的日子里，在一个主要交通路口进行了同步现场测量。我们发现 MA300 报告的 BC 质量浓度强烈相关（斜率范围在 0.73 和 1.01 之间，与 R² = 0.9) 与参考仪器相比，但三个单位之间存在明显的仪器变异性 (15 %)。MA300 报告的 BC 浓度的平均绝对误差范围在 0.44–0.98 ug m ^-3之间，在受野火烟雾影响的污染日观察到的偏差最大。从气溶胶光吸收测量的角度来看，MA300s 倾向于低估吸收系数（b _abs) 跨越五个波长。UV 通道光吸收结果受到最大量的噪声影响，导致源分配分析中的系统偏差。我们调查了 MA300 中最新的非线性 aethalometer 校正协议的应用，发现与板载仪器校正相比，流量波动增强了所有通道的噪声。我们还发现，在野火烟雾影响期间，UV (λ = 370 nm) 通道吸收测量对仪器伪影最敏感。因此，作为传统基于 UV 和 IR (λ = 880 nm) 的 BC 源分配方法的替代方法，在这项工作中，我们测试了用于 BC 源分配计算的蓝色 (λ = 470 nm) 和 IR 波长。MA300采用基于Blue-IR的源分配技术，