Or is there really nothing other than CO2 levels which correlates strongly with the use of portable classrooms and with absenteeism? Perhaps low socioeconomic status has nothing to do with which school districts have more trouble affording permanent buildings? Perhaps higher numbers of children per family are unrelated to which schools are overcrowded?
It's hard to tell, when the bibliography consists of "studies show".
What's sad is that this is still better-than-average science and science reporting. We got an actual transcript, and the correlation seems to be at least a step above the "people who wear parachutes are more likely to die in skydiving accidents!" level which is so good at grabbing headlines.