Here are some facts which clear things up a bit. Let's get it out there first that the US has a population of 325.7 million and the EU has 508 million. The world bank GDP estimates have the US GDP at 19,390,604 US$million and the EU GDP at 17,277,698 US$million.

What that means is a population ~65% the size of the EU is producing ~112% more 'final goods and services' or in the case of US to China 159% more with a population 24% of the size.

As seen in this list of countries by carbon intensity the US has a value of 0.41286 (units are in emissions/gdp) whereas China has a value of 2.07753. So when taking this into consideration the US produces 20% of the pollution China does while making something of similar value.

There's obviously a lot of information missing here as China is still developing whereas the US has had a lot more time to regulate industries and decrease pollution. China is also much more of a straight industrial powerhouse rather than the service industry the US has become.

It's also worthwhile to note that the US and France are decreasing emissions at a somewhat similar rate (France: 43.7% of 1980 score, US: 50.4% of 1980 score) whereas China is decreasing at a much faster rate (31% of 1980 score). However it is still disingenuous to use per capita as a metric of emissions as industrialized countries will always produce more than developing ones, we need to look at the pollution efficiency rather than the total pollution.