Alternative spin on the statistics is 4 times the population of the US but only twice the sulphur emissions.
It's easy to have zero emissions if you are dirt poor and live in a pre-modern society. The correct way to look at it is the amount of energy consumed and pollution emitted per dollar of GDP output. The U.S. is the world leader in those metrics. The power and heavy industries get almost no credit for the hundreds of billions of dollars spent on pollution control and energy efficiency over the past 30 years.
How about no spin and simply calculate the level of pollution coming from each country. On that measure, China puts out 100 times more pollution.