Short-Term Effects of “Polish Smog” on Cardiovascular Mortality in the Green Lungs of Poland: A Case-Crossover Study with 4,500,000 Person-Years (PL-PARTICLES Study)

Previous studies conducted in highly polluted areas have reported associations between air pollution and daily mortality. The Green Lungs of Poland are characterized by unique natural features and a moderate pollution level. We aimed to assess the short-term impact of air pollution on cardiovascular (CVD)-, acute coronary syndrome (ACS)-, and cerebrovascular-related (CbVD) mortality. An analysis with 4,500,000 person-years and a time-stratified case-crossover design was performed. The interquartile range increase in the PM2.5 (OR 1.036, 95% CI 1.016–1.056, p < 0.001) and PM10 concentration (OR 1.034, 95% CI 1.015–1.053, p < 0.001) was associated with increased CVD mortality on lag 0, and this effect persisted on the following days. The effects of PMs were expressed more in association with ACS-related mortality (PM2.5-OR = 1.045, 95% CI 1.012–1.080, p = 0.01; PM10-OR = 1.044, 95% CI 1.010–1.078, p = 0.01) and CbVD mortality (PM10-OR = 1.099, 95% CI 1.019–1.343, p = 0.02). We also noted a higher CVD mortality OR in the cold season for PM10 in cities with area-source domination: Białystok (p = 0.001) and Suwałki (p = 0.047). The short-term impact of PMs on cardiovascular mortality is also observed in moderately polluted areas. This adverse health effect was more apparent in CbVD- and ACS-related mortality, and in the cold season. Further research focusing on the adverse health effects of “Polish smog” is sorely needed.