Yes and years ago many of our coal plants were required to install costly scrubbers to clean their exhaust.
China on the other hand has no such requirements. Also most folks there use coal to heat their homes, and cook their food.
My point is that the bulk of the issue surrounding global warming is the CO2 emissions. Which is a green house gas and cannot be fully contained by using scrubbers. The soot and the grime, mainly effect and is what is causing the haze across her cities. The CO2 emissions, affect everyone.
So, it is still an important point to note, that the US does emit more CO2, on a per capita basis, from coal than China. In other words, the issue shouldn't be the volume of coal China uses, but rather, as you said, whether they use scrubbers or not. Push for China to use scrubbers then. Don't condemn them for using coal. In fact, China would likely need to double it's coal consumption to match the US on a per capita basis.
As a parting comment. I do find it ironic, that the very people, from developed nations, that are so defensive about double standards directed at them, are the very first and most deligent about directing double standards at developing nations.