11.8.1.9 Diesel

Similar concerns apply to attempts to reduce CO₂ emissions through the replacement of gasoline vehicles by more energy-efficient diesel vehicles. Without the most advanced particle filters, that require very-low-sulphur fuel which is not available everywhere, diesel vehicles are a major contributor to population exposure to fine particulate matter, especially of PM_2.5 and finer. Diesel particles have been shown to be more aggressive than other types of particles, and are also associated with cancer (HEI, 1999). Mitigation strategies that increase the use of diesel vehicles without appropriate emission control devices counteract efforts to manage air quality. At the same time, concern has been expressed in the literature about the radiative effects of the emissions of black carbon and organic matter from diesel vehicles, which might offset the gains from lower CO2 emissions (Jacobson, 2002). Although both the US and the EU are moving towards very stringent emission standards for diesel engines, their adoption by the rest of the world may be delayed by years.

11.8.1.10 Practical examples of integrated strategies

The realization of co-benefits has moved beyond a notion or an analytical exercise and is actually reflected increasingly in national regulations and international treaties.

US EPA operates a programme called ‘Integrated Environ-mental Strategies’ that is designed to build capacity to conceptualize co-control measures, analyze their co-benefit potential, and encourage the implementation of promising measures in developing countries. The programme has been active in eight developing countries, resulted in numerous assessments at the urban and national levels of co-benefits, and has helped influence policies leading to efficient measures that address local pollution and GHGs together. The programme is outlined in detail in US EPA (2005).

The European Commission, in its European Climate Change (ECCP) and Clean Air For Europe (CAFE) programmes, explores the interactions between the European Union’s climate change and air pollution strategies and examines harmonized strategies that maximize the synergies between both policy areas (CEC, 2005).

The 1987 Montreal Protocol on Subsances that deplete the Ozone Layer mandates the phase-out of ozone-depleting substances, CFCs, halons, HBFCs, HCFCs, and methyl bromide. Some of the alternatives to these products, which are used primarily in refrigeration and in air conditioning, and for producing insulating foam, have significant GWPs although these are, in many cases, less than those for the CFCs and HCFCs. They also can improve the energy efficiency of some equipment and products in which they are used. In order to investigate the link between ozone depletion and climate change, a Special Report was produced by IPCC and the Technology and Economic Assessment Panel (TEAP) of the Montreal Protocol (IPCC & TEAP, 2005).