Introducing Soot-free Transport

The new year has welcomed more of the same bad air in Delhi and the Valley of Mexico, while Beijing is definitely breathing easier than last winter. Diesel vehicles are a part of the problem in each city, whether they are spewing clouds of black smoke or the pollution is invisible to the human eye. Delhi replaced diesel buses with natural gas decades ago, only to see diesel passenger cars and trucks drive pollution levels back up. Now, as diesel cars continue to flout regulations, some cities have announced plans to ban diesels altogether.

When the air pollution is as thick as it got in Delhi, it can be hard to see the solutions at your fingertips. The ICCT is kicking off the new year with Soot-free Transport, a new network and information resource, precisely to help cities and countries address diesel pollution—one important part of their air pollution problem. Our intent is to provide the tools needed to enact policy measures that will move us to soot-free transportation solutions including clean diesel, natural gas, electric-drive and hydrogen fuel cell technologies.

According to a recent study in the Lancet, in 2016, 4.1 million people died prematurely from tiny particles in ambient air pollution, officially known as PM2.5. This accounted for 7.5% of all deaths worldwide that year. Globally, land transportation is responsible for approximately 10% of PM2.5-related deaths, but that proportion is higher in North and South America, Europe and the Middle East and may be further elevated in urban areas in any region. Each tiny particle is different, but they are mostly composed of black carbon cores (informally, “soot”) with other types of pollutants—organic carbons, metals, toxics, sulfates, and nitrates—sticking to their surface. In the transport sector, soot is formed mostly from diesel engines, while the other particle constituents may be formed in any combustion engine or the atmosphere, where they can glom on to other particles or float freely.

While ambient air pollution is currently responsible for almost half of the total pollution-related deaths—more than war, disaster, and hunger—it is much harder to tally a death count associated with catastrophic climate change. Only one world leader is so, “like, really smart” that he wishes climate change would just make winter a little warmer where he lives and that he is rolling back the effective policies in place to control air and climate pollution. But without additional policy action, air pollution-related deaths could actually increase by more than 50% over the next 30 years. And of course, climate change is just making addressing air pollution even harder, while also starting to have a measurable impact on tally for war, disaster, and hunger.

And that’s why Soot-free Transport is so important. Soot is not only a key component of the most-deadly air pollutant. It is also the second most-critical climate pollutant, allowing us to tackle both issues at the same time. Furthermore, we have a pretty obvious target. Although they make up less than 5% of the global on-road fleet (including motorcycles), heavy-duty diesel vehicles contribute more than 80% of transport-relate emissions of PM2.5 and NOx (a gaseous precursor for particles and ozone—the other major pollutant implicated in air pollution deaths). Black carbon makes up the largest share of particle emissions from heavy-duty trucks and buses, and overall diesel vehicles emit 99% of the black carbon from road transportation. Soot-free technologies—defined as any engine meeting Euro VI or US EPA 2010 standards, or any diesel engine equipped with a diesel particulate filter, natural gas-powered engine, or dedicated electric-drive engine—eliminate 99% plus of these emissions.

Soot-free solutions are commercially available today that can transform the choking, acrid exhaust from the truck and bus fleets of the world. When Australia, Brazil, China, India and Mexico implement new vehicle standards (currently adopted, proposed, or under discussion), feasibly as early as 2021, roughly 80% of the world’s new trucks and buses will be soot free. Battery-electric and hydrogen fuel cell technologies offer soot-free options which, when powered by renewable energy, can also virtually eliminate CO2 emissions, adding to the climate benefits in a big way. For some applications, especially urban buses, these may already be the most cost-effective solutions. For others, they are just emerging.

With Soot-Free Transport, we aim to accelerate the transition to soot-free fleets in cities and countries around the globe. Over the course of the coming year, ICCT will pull together resources, best practices and lessons learned from our own research and the experience of international experts to support national, regional and city governments looking to design, adopt and implement policies needed to eliminate diesel pollution from trucks, buses, and non-road equipment. We will organize these resources for easy access and supplement them with webinars, video interviews, and other training materials.

Soot-free Transport will tackle:

  • Land transport contributions to ambient air pollution, health impacts, and climate change
  • Soot-free engines, aftertreatment technologies and fuels
  • Best practices on soot-free policies for new and in-use vehicles
  • Regulatory design considerations for effective new vehicle standards
  • Maintenance, operational, and cost requirements of soot-free technologies
  • Compliance and enforcement tools and mechanisms
  • City, state, and national policy options to accelerate the transition to soot-free fleets
  • Regulatory analyses to support policy adoption

Soot-free Transport can only be effective if we reach the right people in cities and countries around the world who need this information. Please join and follow our Soot-free Transport groups on LinkedIn and Facebook. Have a soot-free topic that you are grappling with? Let me know ( and we will try to address it.

The truth is that we’ve had ready solutions at hand for the 15+ years that I’ve been working on urban air pollution. Today, soot-free transport solutions are ever more available, with manufacturers committed to offering them in key markets, real progress on fuel quality, and advanced technologies putting even more pressure on the older ones. The world is ready for soot-free solutions and Soot-free Transport is ready to provide them.

Fleets Zero-emission vehicles
Clean air
Emissions control