Lim CC, Hayes RB, Ahn J, et al. - Using a large prospective cohort of US adults with 17 years follow-up (NIH-AARP Diet and Health Study), researchers inquired the links of long-term (annual or warm season average of daily 8-h maximum levels) ozone (O₃) exposure with all-cause and cause-specific mortality. They connected the cohort (n = 548,780) to census tract–level estimates for O₃. They found a significant link of long-term annual average exposure to O₃ with deaths resulting from cardiovascular disease, ischemic heart disease, respiratory disease, and chronic obstructive pulmonary disease in single-pollutant models. Among participants residing in locations with high temperature, a link was identified between long-term O₃ exposure and significantly raised respiratory disease mortality risk. A requirement for the establishment of annual and/or seasonal federal O₃ standards to ensure more appropriate protection of public health from ambient O₃ exposures was suggested by the observed link between long-term exposure to O₃ and increased risk for multiple causes of mortality.