The Institute of Marine Engineering, Science and Technology (IMarEST), in association with the International Council on Clean Transportation (ICCT), has defined Black Carbon and presentation it definition at a recent IMO Sub-Committee on Bulk Liquids and Gases (BLG). While BC is claimed to be second only to CO2 in terms of climate change until now there had been no definition, making it it difficult to introduce any measure to reduce BC emissions.
Black Carbon (BC) is the name given to solid particles emitted during incomplete combustion and is also referred to as 'soot', 'elemental carbon' and 'graphite carbon'. BC contributes to climate change in two ways - first, in the atmosphere where it absorbs sunlight and re-emits the energy as heat. Secondly, when deposited on ice or snow, in addition to warming the surface and air directly, it reduces the surface reflectivity (albedo), causing it to absorb more sunlight.
It is believed that, because it is short-lived, remaining in the atmosphere only a few weeks, reducing BC emissions could have a very rapid and significant effect on the rate of warming.
IMarEST's Chief Executive, David Loosley said: "The definition arrived at by IMarEST and ICCT is that: 'Black Carbon (BC) is strongly light-absorbing carbonaceous material emitted as solid particulate matter created through incomplete combustion of carbon-based fuels. BC contains more than 80% carbon by mass, a high fraction of which is sp2-bonded carbon, and when emitted forms aggregates of primary spherules between 20 and 50 nm in aerodynamic diameter. BC absorbs solar radiation across all visible wavelengths and freshly emitted BC has a mass absorption efficiency of 5m2/g at the mid-visible wavelength of 550 nm. The strength of this light absorption varies with the composition, shape, size distribution, and mixing state of the particle.' Undoubtedly defining it, and publicising that definition, will help awareness and understanding globally of the challenge it provides to the maritime industries."
Source: World Bunkering
