Black carbon aerosols and climate

Using data mining and new data analysis methods, EU-funded researchers gathered critical information on black carbon sources and its atmospheric processing that can be used to improve climate modelling.

Industrial Technologies

Particles in the air affect climate by absorbing solar radiation at differing degrees. Black carbon, a by-product of incomplete combustion of fossil fuels, wood and other biomass, is the strongest light absorber among components of aerosol particles matter. Understanding its role in the ongoing climate change is one of the biggest challenges facing the research community. Much of the uncertainty surrounding the impact of black carbon on Earth’s climate is due to a poor understanding of its mixing state. Single-particle mass spectroscopy is one among a handful of techniques that can be used to assess whether it exists in pure form or primary and secondary species are mixed. The EU-funded project CHEMBC (Chemical and optical properties of black carbon particles) aimed to answer these questions. Researchers in the CHEMBC project developed and applied data mining techniques to convert mass spectroscopy data to quantitative single-particle composition information. The new method enabled apportionment of black carbon sources over Paris, France into freshly emitted local sources and aged particles transported from outside the city. A new data mining approach was also developed to assess the tendency of black carbon aerosol particles to accumulate atmospheric water based on single-particle mass spectroscopy data. Conventionally, the analysis is applied to the bulk aerosol. In CHEMBC, the propensity of every single particle to form new clouds was assessed for the first time. Isolated datasets of single-particle mass spectroscopy measurements collected between 2002 and 2014 in North America, East Asia, North Atlantic, the Caribbean, Western Europe and the Mediterranean basin were merged to produce the first ever global library. This unique dataset has been clustered according to representative particle types to allow the objective analysis of future measurements. CHEMBC has made an important contribution towards the development of a more standardised approach to the assessment of particle mixing state. Moreover, a better understanding of how black carbon is mixed with other aerosol particle species is valuable for improving the accuracy of advanced single particle-resolved climate models. The video with the project’s major breakthroughs can be accessed through this web page.