> That 0.08 g/km figure is using the 'new european driving cycle' which features unrealistically low loads on the engine, engines are known to increase their NO

> That 0.08 g/km figure is using the 'new european driving cycle' which features unrealistically low loads on the engine, engines are known to increase their NOx emissions quite a bit when under load. Doesn't that lend further support to the point that U.S. regulations, while also obviously not perfect, are stronger in this area? > Anyway, NOx is not the only gas that the EU is concerned about, C02 figured very large in the whole reduction program as well. But you were challenging pwthornton's assertion that "The US is also much more concerned with air pollution that affects human health." While CO2 emissions are undesirable, NOx and particulates are what actually kill people in polluted cities.