From “ARB claims diesel engine controls reducing climate change impact in California”:
Black carbon consists of soot particles from the combustion of fuels and other sources. In addition to adverse health effects, the particles have both a warming effect (due to heat absorption) and a cooling effect (due to reflection of sunlight). However, ARB said that this study also showed that the cooling effect predominates and supports growing evidence that it is possible to immediately slow the pace of climate change regionally by reducing emissions of short-lived pollutants like black carbon.
Well I was at Bondi Beach Sydney recently (the best beach outside of California?) And I could smell it before I saw it. Yep, buses, diesel. Nevermind, nature has secured the beach.
Well, that fails to track, doesn’t it? In any case, “climate change regionally” depends on far too many variables to assign any weight to soot from diesel engines.
Reducing soot is a good concept. Keeping transport costs reasonable is a good concept. The evidence we have is that any health benefits to reducing soot below current levels in the US come at a ridiculous cost, which explains the EPA’s desire to do so.