The mass concentration of black carbon (BC) particles in the atmosphere has traditionally been quantified with two methods: as elemental carbon (EC) concentrations measured by thermal–optical analysis and as equivalent black carbon (eBC) concentrations when BC mass is derived from particle light absorption coefficient measurements. Over the last decade, ambient measurements of refractory black carbon (rBC) mass concentrations based on laser-induced incandescence (LII) have become more common, mostly due to the development of the Single Particle Soot Photometer (SP2) instrument. In this work, EC and rBC mass concentration measurements from field campaigns across several background European sites (Palaiseau, Bologna, Cabauw and Melpitz) have been collated and examined to identify the similarities and differences between BC mass concentrations measured by the two techniques. All EC concentration measurements in PM_2.5 were performed with the EUSAAR-2 thermal–optical protocol. All rBC concentration measurements were performed with SP2 instruments calibrated with the same calibration material as recommended in the literature. The observed values of median rBC-to-EC mass concentration ratios on the single-campaign level were 0.53, 0.65, 0.97, 1.20 and 1.29, respectively, and the geometric standard deviation (GSD) was 1.5 when considering all data points from all five campaigns. This shows that substantial systematic bias between these two quantities occurred during some campaigns, which also contributes to the large overall GSD. Despite considerable variability in BC properties and sources across the whole dataset, it was not possible to clearly assign reasons for discrepancies to one or the other method, both known to have their own specific limitations and uncertainties. However, differences in the particle size range covered by these two methods were identified as one likely reason for discrepancies.Overall, the observed correlation between rBC and EC mass reveals a linear relationship with a constant ratio, thus providing clear evidence that both methods essentially quantify the same property of atmospheric aerosols, whereas systematic differences in measured absolute values by up to a factor of 2 can occur. This finding for the level of agreement between two current state-of-the-art techniques has important implications for studies based on BC mass concentration measurements, for example for the interpretation of uncertainties in inferred BC mass absorption coefficient values, which are required for modeling the radiative forcing of BC. Homogeneity between BC mass determination techniques is also very important for moving towards a routine BC mass measurement for air quality regulations.

中文翻译：

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在多个欧洲站点进行野战时，共置的耐火黑碳（rBC）和元素碳（EC）质量浓度测量结果的比较

传统上，大气中黑碳（BC）颗粒的质量浓度可通过两种方法进行量化：通过热光分析测量的元素碳（EC）浓度；当BC质量源自颗粒时，作为等效黑碳（eBC）浓度。光吸收系数的测量。在过去的十年中，基于激光诱导白炽灯（LII）的耐火黑碳（rBC）质量浓度的环境测量已变得越来越普遍，这主要是由于单颗粒碳烟光度计（SP2）仪器的发展。在这项工作中，从欧洲多个背景站点（帕莱索，博洛尼亚，已对Cabauw和Melpitz进行了整理和检查，以确定通过两种技术测量的BC质量浓度之间的异同。PM中的所有EC浓度测量_2.5使用EUSAAR-2热光协议进行。所有的rBC浓度测量均使用SP2仪器进行，该仪器使用与文献中推荐的相同的校准材料进行校准。考虑到所有五个数据点的所有数据点时，单运动水平的rBC与EC的中值质量浓度比的观测值分别为0.53、0.65、0.97、1.20和1.29，几何标准偏差（GSD）为1.5。广告活动。这表明在某些竞选活动中，这两个数量之间出现了系统性的偏差，这也导致了较大的总体GSD。尽管整个数据集中的BC属性和来源存在很大差异，但无法明确指出一种或另一种方法出现差异的原因，两者都有其特定的局限性和不确定性。然而，这两种方法所涵盖的粒径范围差异被认为是导致差异的一个可能原因。总体而言，观察到的rBC与EC质量之间的相关性揭示了具有恒定比率的线性关系，从而提供了明确的证据表明这两种方法本质上都可以量化大气气溶胶具有相同的特性，而在测量的绝对值中可能会出现系统差异，最高可达2倍。这一发现为当前两种最先进技术之间的一致性水平提供了重要依据，对基于BC质量的研究具有重要意义。观察到的rBC与EC质量之间的相关性揭示了具有恒定比率的线性关系，因此提供了明确的证据，表明这两种方法实质上量化了大气气溶胶的相同特性，而测量绝对值的系统差异可能会发生2倍。这一发现为当前两种最先进技术之间的一致性水平提供了重要依据，对基于BC质量的研究具有重要意义 观察到的rBC与EC质量之间的相关性揭示了具有恒定比率的线性关系，因此提供了明确的证据，表明这两种方法实质上量化了大气气溶胶的相同特性，而测量绝对值的系统差异可能会发生2倍。这一发现为当前两种最先进技术之间的一致性水平提供了重要依据，对基于BC质量的研究具有重要意义。浓度测量，例如用于解释推断的BC质量吸收系数值的不确定性，这是对BC的辐射强迫进行建模所必需的。BC质量测定技术之间的同质性对于迈向空气质量法规常规BC质量测量也非常重要。