Short-Term Ozone Exposure and Daily Mortality in Suburban and Rural Areas of Southern Europe

Ozone (O₃) is a major air pollutant with significant health effects, including increased respiratory and cardiovascular mortality. While previous research has largely focused on urban areas, this study assesses the association between maximum 8-hour O₃ concentrations and non-accidental mortality, cardiovascular and respiratory mortality in suburban and rural areas of Spain. We conducted a nationwide time-series analysis across 122 cities between April and September 2017, using Poisson regression models adjusting for daily maximum temperature and provincial variability. Distributed lag models were applied to estimate the cumulative effects of ozone exposure on mortality, considering lags from 0 to 30 days. For each 10 µg/m³ increase in 8-hour maximum O₃ concentration, a significant increase in all-cause mortality risk of 2.3% was observed, with a peak at lag 2. Cardiovascular mortality increased by 2.4%, also peaking at lag 2, while respiratory mortality showed the strongest association with a 4.3% rise at lag 1. A secondary mortality risk increase was observed at lags 24-28, suggesting potential delayed effects of O₃ exposure. These findings highlight the need for targeted public health interventions to mitigate the impact of ozone pollution in non-urban populations.