Impact of Air Pollution and Outdoor Temperature on the Rate of Chronic Obstructive Pulmonary Disease Exacerbations

Abstract

BACKGROUND: Environmental pollution can be one of the main risk factors for acute exacerbations of chronic obstructive pulmonary disease (COPD). AIM: To study the relationship between air pollution, outdoor temperature and exacerbations of COPD. MATERIALS AND METHODS: COPD patients (n=1432) were followed up for one year. The levels of particulate matter up to 10 μm (PM10), nitrogen dioxide (NO2), sulfur dioxide (SO2) and outside temperatures were collected from the Environmental Agency database. RESULTS: A total of 309 acute COPD exacerbations (AECOPD) were recorded in the analysis. The daily mean concentrations of PM10 were found to correlate significantly with the daily mean concentrations of NO2 and SO2 (ρ 0.34 and ρ 0.49, respectively; p=0.0001). The negative correlations between the daily mean temperature and the daily mean levels of PM10, NO2 and SO2 were also significant (ρ -0.44, ρ -0.11, and ρ -0.37, respectively; p=0.0001). The daily number of AECOPD correlated with the mean levels of PM10 in the previous six days (ρ 0.14; p=0.02) and the lower outdoor temperature (ρ -0.2; p=0.001). The negative correlation between the daily number of AECOPD and the mean daily temperature was stronger in days with levels of PM10 above 50 μg/m3 (ρ -0.3 p=0.02 vs. ρ -0.18 p= 0.01). CONCLUSION: Lower daily mean temperatures were associated with the levels of air pollutants. The level of PM10 correlated with the levels of the other air pollutants. The daily number of AECOPD was found to correlate weakly, but signifi cantly with the mean level of PM10 in the previous six days.