In 2015, Los Angeles suffered from the Aliso Canyon gas leak, where gas leaked out of a well near LA. The carbon footprint may have been larger than that of the Deepwater Horizon Leak. In reaction to the leak, many schools invested in air filters (for about $700 to $1000). This provided a very nice natural experiment. Michael Gilraine found in a working paper that these air filters have surprisingly large positive effects on the students’ performance. You may also be interested in this article about health and cognitive problems associated to air pollution.