Mullen and colleagues confirm how important it is to breathe clean air and their work supports efforts to make sure air inside buildings is filtered. The researchers report that “Fine particulate air pollution is harmful to children in myriad ways. While evidence is mounting that chronic exposures are associated with reduced academic proficiency, no research has examined the frequency of peak exposures. . . . [the researchers examined] the percentage of third grade students who tested below the grade level in math…