Hospitalizations of COPD patients and the level of air pollution and meteorological conditions in Poland in 2012-2019

Air pollution is an important risk factor leading to exacerbations of respiratory diseases such as chronic obstructive pulmonary disease (COPD). Weather conditions influence the amount of emissions and the persistence of pollutant concentrations. The study aimed to analyze the impact of air pollution and meteorological elements on the number of daily emergency hospitalizations of patients with COPD in 2012-2019 in Poland. Data on adults aged 40 years and over hospitalized with COPD (code J44 according to ICD-10) were obtained from the hospital morbidity register kept by NIZP PZH-PIB. Data on air pollution (PM10, PM 2.5, NOx, SO2, NO2) came from the reports of the Inspectorate of Environmental Protection, and the values of meteorological elements came from the IMGW. The analysis included 7-day moving averages of hospitalizations and environmental components. Cross-correlation and machine-learning methods were used. The highest correlations between the increase in the number of emergency admissions of COPD patients were found for the concentration of SO2 pollutants with a delay of 14 days (r=0.76) and, respectively, PM2.5 (15 days, r=0.65), PM10 (5 days, r=0.60), NO2 (19 days, r=0.57), NOx (30 days, r=0.53). With an increase in the values of elements describing thermal and humidity conditions, a decrease in the average weekly number of hospitalizations was observed, respectively: Tmax (17 days, r=-0.76), Tmin (16 days, r=-0.76), Td (11 days, r=-0.79) and e (15 days, r=-0.72). Random Forests methods showed that the most important elements in predicting changes in the number of COPD emergency admissions in Poland were SO2 concentrations and air temperature values.