Multiscale Chemical Composition of Carbonaceous particles and Coatings (MC4)

黑碳（BC）颗粒是大气科学中一个重要且高度相关的研究领域。这些物质是人类活动产生的，以火灾和运输排放的烟尘形式大量存在。自前工业时代以来，大气中的BC浓度一直在增加，对全球气候的影响是变暖，因为这些颗粒可以吸收入射辐射。此外，这些粒子有能力通过局部大气变暖来改变区域气候和天气模式。然而，BC对大气的确切影响很难预测，因为确切的光吸收特性根据颗粒的确切来源而变化。此外，大气过程可能导致颗粒与其他颗粒混合，并通过气相反应获得涂层。这些效应实质上改变了气溶胶的吸收特性，但很难预测。传统上，由于缺乏合适的仪器，无法直接测量BC的化学成分和颗粒上的任何涂层，因此对这些影响的研究受到阻碍。为了满足这些需求，烟尘颗粒气溶胶质谱仪（SP-AMS）正在通过Aerodyne Research Inc.，液滴测量技术和曼彻斯特大学。该方法使用近红外激光蒸发含有BC的颗粒，然后使用质谱法分析所得蒸汽。由于不含BC的颗粒不吸收激光，因此无法检测到。通过这种方式，SP-AMS选择性地仅测量BC颗粒及其涂层，因此该仪器可用于选择性地研究其涂层的混合状态和化学成分。碳质颗粒和涂层的多尺度化学组成（MC 4）将使用这种新仪器与一套其他测量方法相结合，研究大气中BC颗粒的来源和演变，这反过来将导致更好的模型处理和更准确的BC气候影响预测。此外，还将在实验室开展开发工作，以提高仪器灵敏度和数据质量，准确确定检测极限，并制定操作规程。这将最大限度地提高后续实验工作的效率。测量将在洛杉矶、曼彻斯特和北诺福克海岸的韦伯恩大气观测站进行。需要各种各样的地点来收集各种各样的气溶胶。将涂层和混合的测量结果与基于自动过滤器的方法的光吸收测量结果进行比较。这些将与基于气相VOC测量的气溶胶自排放以来所经历的化学处理量的估计值进行比较。不同来源和类型的BC颗粒将被识别和使用数值因子分析表征。这些研究的结果将推动对建模界有用的参数化。这将有助于更准确地评估BC颗粒在其大气寿命过程中的气候影响，并导致更准确的区域和全球气候预测。

Black carbon (BC) particles are an important and highly relevant area of study in atmospheric science. These are produced in large quantities by human activities in the form of soot from fires and transport emissions. Concentrations of BC in the atmosphere have increased since pre-industrial times and the effect on global climate has been one of warming, as these particles can absorb incident radiation. In addition, these particles have the ability to alter regional climate and weather patterns through localised warming of the atmosphere. However, the exact effects of BC on the atmosphere are hard to predict, as the exact light-absorbing properties vary according to the exact source of the particles. In addition, atmospheric processes can cause the particles to become mixed with others and obtain coatings from gas phase reactions. These effects substantially change the absorption properties of the aerosol but are hard to predict. The study of these effects has traditionally been hampered by the lack of suitable instrumentation that can directly measure the chemical composition of BC and any coatings on the particles. To address these needs, the Soot Particle Aerosol Mass Spectrometer (SP-AMS) is being developed through a partnership between Aerodyne Research Inc., Droplet Measurement Technologies and the University of Manchester. This uses a near infra red laser to vaporise particles containing BC before the resultant vapours are analysed using mass spectrometry. Because particles that do not contain BC do not absorb the laser light, these are not detected. In this manner, the SP-AMS selectively measures only BC particles and their coatings, so therefore this instrument can be used to study the mixing state and the chemical composition of their coatings selectively. Multiscale Chemical Composition of Carbonaceous particles and Coatings (MC4) will use this novel instrument in conjunction with a suite of other measurements to study the sources and evolution of BC particles in the atmosphere, which will in turn lead to better model treatments and more accurate predictions of BC's climatic impacts. In addition, development work will take place in the laboratory to improve instrument sensitivity and data quality, accurately determine detection limits and formulate an operational protocol. This will maximise the effectiveness of subsequent experimental work. Measurements will take place in Los Angeles, Manchester and the Weybourne Atmospheric Observatory on the north Norfolk coast. A wide variety of sites is needed to characterise a broad range of aerosols. The measurements of coating and mixing will be compared with optical absorption measurements from automated filter-based methods. These will compared with estimates of the amount of chemical processing that the aerosol has undergone since emission based on gas phase VOC measurements. Different sources and types of BC particles will be identified and characterised using numerical factor analysis. The results from these studies will drive parameterisations that will be of use to the modelling community. This will allow the more accurate evaluation of the climatic impacts of BC particles over the course of their atmospheric lifetimes and lead to more accurate regional and global climate predictions in general.