Global progress toward soot-free diesel vehicles in 2019
This report assesses global progress in 2019 toward reducing black carbon emissions from diesel on-road light-duty and heavy-duty vehicles. As of July 2019, 39 countries have implemented “soot-free” standards for new heavy-duty diesel engines that achieve a 99% or greater reduction in black carbon emissions compared with older-technology diesel engines. Five countries have adopted such standards for implementation before 2025, and at least six countries are planning to complete the transition to ultralow-sulfur diesel. The authors estimate that currently adopted policies will reduce global on-road diesel black carbon emissions to 40% below 2010 levels by 2030. A 75% reduction in global on-road diesel black carbon emissions is achievable by 2030, but only if virtually all countries implement soot-free standards in the 2020 to 2025 time frame. Adhering to this timeline could avoid roughly $1 trillion (U.S.) in cumulative societal costs over the next decade.
There remains substantial heterogeneity in progress toward soot-free vehicles and fuels among G20 economies and Climate and Clean Air Coalition member countries. In countries that have recently adopted soot-free standards, the main challenges are to ensure effective compliance and avoid delays in implementation. In countries that have ultralow-sulfur diesel available, we recommend adopting soot-free vehicle and engine standards and scheduling their implementation as soon as possible. The experiences of some countries, such as India, demonstrate the feasibility and greater net benefits of leapfrogging to soot-free standards as opposed to making incremental advances. In countries with higher-sulfur diesel, securing ultralow-sulfur diesel should be prioritized to enable the introduction of soot-free vehicle and engine standards. In countries with multiple fuel grades, ensuring nationwide availability of an ultralow-sulfur diesel grade can enable the introduction of soot-free vehicle and engine standards several years ahead of the transition for all fuels nationwide; in such cases, differential taxes can provide a financial incentive for refiners, importers, and consumers to transition to ultralow-sulfur fuels.
In many regions, progress toward soot-free standards can be accelerated through cooperation among countries. In some regions, these activities have already resulted in joint technical work plans that lay out the steps to adopting and implementing soot-free standards. For these regions, the next logical step is to implement these joint technical work plans; in other regions, we recommend adapting these work plans to reflect the circumstances of participating countries. In both cases, the findings of this assessment stress the urgency for action and the societal benefits of rising to the challenge.