Comparatively, yes.What would cause that much soot? Just idling causes massive soot?
Modern Diesel engines have very high pressure injection and a nice injector spray pattern compared to old engines. Old engines had pintle injectors that were like squirt guns, and the fuel spray depended on air tumble in the swirl chambers to mix the fuel. When fuel was pennies a gallon, no one cared if the exhaust was a little dirty with wasted fuel going out the tailpipe because it was so cheap.
Modern Diesel engines can run extremely clean exhaust with clean air in the intake... but then combustion temperatures are so high that NOx production is also high. It's a constant balancing act to get enough EGR in the engine to cool the combustion temperature (because less O2 means lower combustion temperatures) to get less NOx output. The new problem created with this EGR flow is that we are wasting fuel because the lower O2 level in the cylinders leaves some of the fuel unburned - it comes out as soot.
At idle, the engine is typically running very high EGR levels. I've heard it is up to 50% EGR at idle to keep NOx production low, and I believe it has to do with exhaust temperature not being high enough for the NOx catalyst to function efficiently. If the catalyst can't clean up the exhaust the only way to keep NOx low is to not produce it in the first place.
Comparatively speaking, lots of soot is generated at idle because the EGR is choking the engine so much.