Can air purifiers improve students' academic performance?

After purifiers were installed in southern California classrooms following a gas leak, students saw gains on math and English tests

A 2015 gas leak that belched toxic chemicals into the air and spread panic may have indirectly led to higher student test scores.

In the days after a gas leak was discovered in Aliso Canyon, 30 miles north of Los Angeles, thousands of residents were evacuated from the area, many of whom reported headaches, nausea, stomach aches, dizziness or breathing problems. Students from two nearby schools were relocated and 18 other schools were impacted.