Even more on the death of SO2 Cap'n Trade

In response to this post this morning, reader MikeMcK asks:

I'm curious to see a chart showing SO2 emissions over that same time...

From the EPA's Air Trends:

"The blue band shows the distribution of air pollution levels among the trend sites, displaying the middle 80 percent. The white line represent the average among all the trend sites. Ninety percent of sites have concentrations below the top line, while ten percent of sites have concentrations below the bottom line."