Influence of particulate matter pollution on emergency department visits for COPD exacerbations. A time series.

<bold>Introduction:</bold> Environmental pollution has a significant impact on health, particularly concerning respiratory diseases. The objetive of this study is to asses the association between ambient levels of particulate matter (PM10, PM2.5) and COPD exacerbations in the emergency department(ED). <bold>Patients and Methods:</bold> A retrospective time-series ecological study was conducted on emergency department visits for episodes of COPD exacerbation between January 1, 2010, and December 31, 2019, in the western area of the city of Valladolid. The study utilized a generalized linear model (Poisson regression) to estimate the relative risk (RR) and attributable fraction. The model was adjusted for various confounding variables, including climatological factors, season of the year, and weekends. Pollution levels were considered for the day of the visit and the preceding days (lags 0, -1, -3, -5). <bold>Result:</bold> A total of 2,045 patients diagnosed with COPD were included, resulting in 5,233 visits to the ED during the study period. The median number of visits per day was 1.43, ranging from 0 to 8. The median age of the patients was 79 years, with 75% of them being male. Regarding PM2.5 values, the daily median concentration was 11.5 µg/m3. The daily median of PM10 was 17.3 µg/m3. In the multivariable analysis adjusted for meteorological variables, season, and weekend, both PM2.5 and PM10 showed an association with lag-3: RR 1.052 (95%CI 1.009-1.097) and 1.038 (95%CI 1.008-1.069) respectively. <bold>Conclusion:</bold> A significant association has been found between elevated ambient levels of particulate matter and the frequency of emergency room visits for COPD exacerbation in an area with low pollution levels.