DNV GL has seen the need to look more closely at the effect of PM and BC emissions from shipping.Particulate matter (PM) and black carbon (BC), a fraction of PM, have received increasing public attention,as they affect human health and the climate.Additionally, ships’ emissions take place in close vicinity to shore. Plumes are often visible to the public in harbor areas and therefore receive more and more press coverage.
Particulate matter (PM) is solid particles and liquid droplets suspended in air. PM varies in both size and composition. PM is divided into three different size categories − PM10, PM2.5 and PM0.1 − which are distinguished based on the aerodynamic diameter.The main source of anthropogenic particulate matter (PM) is the combustion of various sources of hydrocarbons, including coal, all fuels and biomass. PM is composed of different chemicals. Black carbon (BC) is one of these fractions, organic matter (OM), various metals, nitrates and sulphates are the other main constituents.
The term “PM” addresses the health and the climate effect at the same time. The IMO has already addressed the PM emissions indirectly via the reduction of the fuel sulphur content. The global fuel sulphur reduction scheme
was adopted within the framework of MARPOL, in its revised version, in 2008. About five years ago, the IMO joined the global discussion on black carbon in order to address the detrimental “climate effect” it has in arctic areas, as existing climate models are experiencing difficulties in explaining the amount of ice melting. It seems that the reduced albedo effect has a greater impact than experts previously envisaged, and forecasting models require continuous input based on the latest research. More advanced BC emission factors are also needed in order to show which operational factors influence BC emissions. These could include engine load, fuel quality, maintenance condition, etc.
After defining what black carbon means for shipping at the IMO in 2015, this issue and its implications for possible regulations for the shipping industry need to be investigated from scratch. The scientifically correct definition of BC as such was an achievement, but it seems that it comes with a significant drawback. The commercially available measurement devices for BC were developed and used for measuring BC as “immissions”. This means that they are effective in measuring BC in environments with high air dilution, such as the arctic. It is still unclear whether this technology would be adequate for measuring BC emissions in a tail pipe with much higher emission concentrations. Currently, there is no standard methodology for carrying out these measurements. Therefore, basic research tests (measurement campaigns) are necessary in order to gather more experience in this field, to test available equipment and to compare the results with those of established PM emission measurement technology. Another challenge created by the definition of BC is that it is defined according to the following four properties: light absorption, refraction, insolubility in water and its existence as aggregated carbon spherules. Existing BC measurement devices are unable to measure black carbon by applying all four BC characteristics at the same time.
Hence, additional work is necessary to test different devices which rely on different properties and check whether they show similar or (ideally) equal BC results. The review of the regulatory schemes in place in other transport sectors has revealed that BC emission legislation does not yet exist. Other transport sectors focus on regulating PM emissions, and the strictness of the emissions limits varies depending on a regulation’s application (road, train, non-road mobile machinery, etc.), though we expect a general trend towards stricter PM limits. Taking into account the challenges faced in trying to measure BC emissions from shipping, it would be premature to make any predictions regarding potential regulatory frameworks which may govern BC emissions from shipping in the future. The best abatement technologies can only be identified when it is clear what kind of technology will be available for measuring BC in shipping.
Further details may be found by reading the brochure for black carbon below
Source & image credit: DNV GL