Background: Recurring winter smog episodes, recently observed in Poland, have inspired the researches to assess the epidemiological situation concerning the registered exacerbations of respiratory diseases related to worsening of the ambient air quality. Material and Methods: The model comprising the ecological study results and secondary epidemiological data on registered outpatient visits and hospitalizations in the Silesian voivodeship was used. We assessed the effect of smog observed in January 2017 on the number of acute respiratory disorders registered in that month. Aerosanitary situation was obtained from the Provincial Inspectorate for Environmental Protection in Katowice database. Results: It was documented that the increase in PM_2.5 concentration (with simultaneously observed unfavorable meteorological parameters) was related to a higher number of acute respiratory disorders registered daily. Moreover, the increase in the number of outpatient visits due to asthma exacerbation or bronchitis was observed on the first day of episode, and hospitalizations took place with delay of 1–2 days. Conclusions: The preliminary results indicate the relationship between worsening of ambient air quality during the winter smog and the increase in daily number of registered outpatient visits and hospitalizations due to acute respiratory diseases. Med Pr 2018;69(5):523–530