Transport solutions

Reducing black carbon emissions with cleaner fuels and vehicles

The engines used in transport, construction, and power generation are essential components of our modern lifestyles, mobility, and even electricity generation. Many of these engines however often run on lower-quality fuels such as diesel and high-sulphur fuels, which emit large amounts of black carbon and other toxic pollutants. Transport alone comprises over 20% of global black carbon emissions.  
Concentrations of black carbon from transport are typically highest in urban areas, but are also concerningly high in the Arctic, where the black carbon emissions from international shipping (and other sources) are having a disproportionate effect on the melting of snow and ice. Accelerated snow and ice melt creates further warming momentum towards dangerous climate tipping points by reducing the reflection of the sun’s light and heat and speeding up sea-level rise.  

As the world becomes increasingly urbanised, transport demands are predicted to increase by nearly 50% by 2030. This will translate into an estimated additional 26,000 tonnes of black carbon emitted in 2030. Changing lifestyles and consumption patterns are also driving up demand for shipping. Between 2015 and 2019, the Arctic saw a 85% rise in black carbon due to increased shipping traffic.  

Not only does black carbon in diesel exhaust pose a significant health risk as a known human carcinogen and cause of chronic illness, but it is also a potent climate warmer. Black carbon has a warming impact up to 1,500 times stronger than CO2 per unit of mass. Its impacts are not evenly distributed globally however, with the most pronounced warming effects occurring in areas of concentration and on areas of snow and ice cover.  

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Main Emissions Sources

Trucks, buses and other diesel cars are the primary source of black carbon in vehicles and engines, followed by off-road diesel engines, including locomotives and other heavy-duty equipment. On-road gasoline engines and international marine vessels also contribute significantly to the sector’s emissions. Road and sea transport together released nearly 4.8 million tonnes of black carbon in 2000. 

Developed countries which have been implementing higher fuel quality standards and particle filter regulations for transport are seeing black carbon emissions gradually drop. In developing countries, however, emissions are growing as transport demand increases and regulations lag behind best-practice. 

Trucks and Buses
Truck, Black Carbon, Transport, CCAC, Photo by Wolfgang Hasselmann on Unsplash

Most buses and heavy-duty trucks rely on diesel engines that emit dangerous levels of particulates, including black carbon. Rising demand for freight transport means heavy vehicles contribute an increasing share of black carbon emissions. 

Shipping, CCAC, Black Carbon, Photo by Mika Baumeister on Unsplash

The shipping industry’s environmental footprint is equal to the 6th largest emitter of climate emissions in the world. This includes being a major contributor of  black carbon emissions, particularly in Arctic areas where black carbon accelerates snow and ice melt.

Diesel Generators
Generators, Diesel, CCAC, Black Carbon, photo by Rusty Watson on Unsplash

Diesel generators are an important source of electricity for communities lacking access to reliable power. They are a significant source of black carbon however and an inefficient form of power production. 


Black carbon emissions must fall across all sectors by at least 35% from 2010 levels by 2050 if we are to have any chance to limit global warming to 1.5 °C. 
Existing measures to improve fuel standards are reducing black carbon emissions. If all new heavy-duty vehicles were soot-free by 2025, that would achieve a 75% reduction in black carbon emissions. Full implementation of the Global Strategy to Introduce Low Sulfur Fuels and Cleaner Diesel Vehicles could reduce small particulate and black carbon emissions from cars, buses and trucks by over 90% by 2030. 

Successful implementation of the strategy would reduce cumulative black carbon emissions by 7.1 million tons by 2050, leading to 85% fewer black carbon emissions. This would reduce carbon-dioxide equivalent emissions by 14 trillion miles of travel by passenger vehicles. 

What Can Be Done

Improving the health, climate and environmental impact of the vehicles and engines sector requires regulation and implementation monitoring. Globally, Euro-VI fuel standards need to be adopted across all emissions sources. Diesel particle filters also need to become mandatory for all sea and land vehicles.  
Specific 2030 and 2050 milestones for new regulations have been identified for all emitters in the heavy-duty vehicles and engines sector: 
Cleaner Fuels and Vehicles 

  • By 2030, all countries adopt ultra-low sulphur diesel and minimum Euro 6/VI emission standards 

  • Global soot-free vehicle standards for international trade (no dumping of dirty used vehicles) 

  • By 2050, zero tailpipe emissions and 100% elimination of fossil-based fuels for heavy-duty transport 

Non-Road Mobile Machinery and Stationary Engines 

  • By 2030, countries adopt standards for soot-free non-road mobile machinery and stationary diesel engines.  All countries adopt ultra-low sulphur diesel and minimum EU Stage V emission standards. 

  • By 2050, zero tailpipe emissions, 100% elimination of fossil-based fuels- engines for non-road mobile machinery and stationary diesel engines 

Marine and Inland Water Transport 

  • Advocate for the International Maritime Organization to adopt a black carbon emission standard for all new ships and a methane emission standard for new LNG-fuelled ships. 

  • Develop diesel emissions policies for inland water transport in relevant countries by 2030

Green Freight 

  • Significantly reduce emissions of black carbon, PM and other pollutants and GHGs from the sector by enhancing existing, and developing new, green freight programs 


Reducing black carbon emissions from the heavy-duty vehicles and engines sector will have numerous benefits for human health, agriculture, and ecosystems. 
This is particularly the case for snow and ice melt exacerbated by black carbon. When deposited on ice and snow, black carbon and co-emitted particles reduce surface albedo (the ability to reflect sunlight) and heat the surface. Overall, maximum reductions to black carbon could lead to a reduction of approximately 0.2°C  of warming over the next 20 to 40 years. 

Black Carbon is also responsible for premature deaths of children from acute lower respiratory infections such as pneumonia.  Each year, approximately 4 million deaths are associated with long-term exposure to PM2.5 air pollution. Full implementation of desulphurisation and vehicle emission controls to achieve 2050 sectoral goals are estimated to cost around $1.1 trillion. The benefits in avoided mortalities alone in the same timespan however – 470,000 fewer deaths per year – are estimated at $18 trillion. 

In the area of environmental benefits, black carbon’s impacts on changing rain patterns can have far-reaching consequences for both ecosystems and human livelihoods. For example by disrupting monsoons critical for agriculture in large parts of Asia and Africa.  

In combination with tropospheric ozone, black carbon also contributes to over 50 million tonnes of staple crop losses globally each year. Areas with concentrated black carbon emissions stand to gain the most substantial benefits from emissions reductions. 

What we do

In 2016, the CCAC High Level Assembly brought together 36 countries to recognize and fully endorse the Global Sulphur Strategy’s approach and targets.  In the resulting Marrakech Communique, countries pledged to reduce black carbon emissions through cleaner diesel fuels and vehicles by “adopting, maintaining, and enforcing world-class diesel fuel quality and tailpipe emissions standards for on road light and heavy-duty vehicles in our markets.” 

Formulated by coalition partners – the Government of the United States of America, the Government of Canada, the Government of Switzerland, the United Nations Environment Programme and the International Council on Clean Transportation – the Strategy provides specific recommendations for action country-by-country based on market analysis, a refinery analysis, a health benefits analysis and several case studies. 

In addition, the CCAC is active in promoting harmonised regional standards for the transition to ultra-low sulphur diesel fuel & minimum Euro 6/VI emission standards in member countries. 

We also support “committed” governments with policy and technical assistance on regulations, policies, standards, and laws that reduce black carbon and CO2. For example, CCAC has recently supported Cambodia and Cote d’Ivoire in planning for and implementing higher fuel standards and soot-free buses respectively.  

Our Heavy-Duty Vehicles and Engines Hub also promotes knowledge sharing between members. This includes sharing best practices among regional and municipal governments, as well as engaging with manufacturers and fleet operators on the technological needs to electrify non-road engines and reduce manufacturing of machinery without diesel particulate filters. 

The CCAC also continues to provide scientific, technical, and political support in International Maritime Organisation negotiations on the reduction of SLCP emissions from the marine sector. 

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