Short-Term Effects of Air Pollution on Coronary Events in Strasbourg, France-Importance of Seasonal Variations

The aim of this study, is to investigate the effects of a short-term exposure to air pollutants, as assessed by Nitrogen dioxide (NO₂), Particulate Matter PM_2,5 and PM₁₀ concentrations, on coronary event onsets in Strasbourg, France. An observational, analytical, retrospective, epidemiological study was conducted in Strasbourg between 1 January 2012 and 31 December 2014. Higher daily coronary events rates were evidenced when NO₂ concentrations were measured above 40 µg/m³ (1.258 (95% CI 1.142-1.374) vs. 1.110 (95% CI 1.033-1.186); p = 0.015). The NO₂ concentration was higher than 30 µg/m³ for 677 days (61.8%). Higher daily coronary events rates were evidenced when NO₂ concentrations were measured above 30 µg/m³ (1.208 (95% CI 1.128-1.289) vs. 1.067 (95% CI 0.961-1.172) p = 0.009). A marked seasonality of NO₂, PM_2.5, and PM₁₀ concentrations characterized by an increase during winter and a decrease during the summer could be established. The seasonality of coronary events was evidenced simultaneously. After adjustments were made to account for the time and the month, no independent impact of NO₂, PM_2.5 or PM₁₀ on daily coronary events could be demonstrated.