Diesel

Fine particles penetrate deep into the lungs. A recent study of leading public health risks ranked ambient fine particle pollution ninth among all risk factors in 2010, contributing to 3.7 million deaths in 2012. Black carbon is the second largest contributor to human-induced climate warming to-date, after carbon dioxide. All major OECD economies have dramatically reduced fine PM and BC emissions from heavy-duty diesel vehicles through a combination ultra-low sulfur diesel fuel and diesel emission control technologies; there is up to a 99 per cent removal efficiency with diesel particulate filters.

Desulfurization refers to the gradual move to low sulfur fuels. Most developed countries have now moved to fuels with a sulfur content of 50 parts per million or even 15 or 10 parts per million (ppm). Reducing fuel sulfur levels is a vital precondition for reducing the health impacts associated with transportation. Fuel sulfur directly increases production of fine particulate matter (PM2.5) in vehicle exhaust. PM2.5 is a dangerous pollutant associated with heart disease, lung cancer, and a range of other harmful health effects. Low sulfur fuels are necessary for cleaner engines (for example high compression diesel engines) and high fuel sulfur levels also interfere with the performance of vehicle emissions control equipment designed to remove small particulates and other pollutants from the exhaust stream (for example particulate filters and catalysts).

Green freight refers to the efforts of the freight sector to help reduce greenhouse gas emissions and air pollutants and improve fuel efficiency across the global supply chain while maintaining competitiveness and economic growth. By reducing the amount of energy (i.e., fuel use) associated with freight transport through a range of measures, businesses can reduce costs and become more competitive. These efficiency measures invariably lead to emissions savings that result in broader benefits for society and the environment. Freight movement is largely driven by diesel-powered cargo vessels, trucks, and trains. While diesels are the workhorses of the transport sector and relatively energy efficient (as compared to gasoline vehicles or jet aircrafts), their combined contribution to transportation-related climate warming greenhouse gases and other short-lived climate pollutants, particularly black carbon, is significant.

Soot-free engine technologies are those that achieve at least a 99% reduction in tailpipe black carbon emissions compared to uncontrolled diesel exhaust. These technologies include any diesel or alternative fuel engines certified to Euro VI or US 2010 emission levels.

As an example, soot-free buses can be powered by a wide range of fuels including fossil diesel or compressed natural gas (CNG), biogas, or other liquid biofuels, and electric drive engines including hybrid drive, fuel cell, and battery electric drivetrains. A soot-free bus – be it diesel, natural gas or electric – will emit 99% less tailpipe PM2.5 and 85% less black carbon compared to a diesel bus without any emission controls.