Alignment of policies to maximize the climate benefits of diesel vehicles through control of particulate matter and black carbon emissions

Diesel vehicles offer greater fuel-efficiency and lower greenhouse gas emissions at a time when national governments seek to reduce the energy and climate impacts of the vehicle fleet. Policies that promote diesels like preferential fuel taxes, fuel economy standards and greenhouse gas emission standards can produce higher emissions of diesel particulate matter if diesel particulate filters or equivalent emission control technology is not in place. This can undermine the expected climate benefits of dieselization and increase impacts on public health. This paper takes a historical look at Europe to illustrate the degree to which dieselization and lax controls on particulate matter can undermine the potential benefits sought from diesel vehicles. We show that countries on the dieselization pathway can fully capture the value of diesels with the adoption of tailpipe emission standards equivalent to Euro 6 or Tier 2 for passenger cars, and fuel quality standards that limit the sulfur content of diesel fuel to no greater than 15 ppm. Adoption of these policies before or in parallel with adoption of fuel consumption and greenhouse gas standards can avert the negative impacts of dieselization.