Some studies [23–25, 27, 33, 34], however, have found noevidence of an association for NO2, ozone, or PM10 withcognitive impairment. Across the studies, the component ofambient air pollution most frequently assessed in relation tocognitive function was PM2.5 [21–27]. Importantly, most ofthese studies [21–26] supported an association with cognitivefunction, except for the work by Loop et al.