The Impact of Air Quality Index Threshold on COPD Morality

Background: Air pollutants can increase the risk of respiratory diseases, particularly chronic obstructive pulmonary disease (COPD). It is essential to determine the threshold levels of various pollutants in specific areas, as the World Health Organization (WHO) has reported that current air quality often exceeds recommended guidelines. Methods: A regression discontinuity design (RDD) was used to analyze the air quality index (AQI) for six pollutants (PM2.5, PM10, O3, NO2, CO, and SO2), assessing the effects of cut-points. A linear mixed-effects model (LMM) was applied to examine the interaction between these six pollutants and COPD mortality, and to make predictions. Results: The distribution of the six pollutants on either side of the cut-points revealed differences. CO had the greatest impact on COPD mortality, with a coefficient estimate of 0.475 (p-value = 0.0808, suggesting a significant effect on COPD mortality). PM2.5 had the smallest effect, with a coefficient estimate of -0.0147. Conclusions: This study highlights the need to address the emission profiles of air pollutants to reduce their impact on COPD mortality. Given the importance of human intervention in determining cut-points in the data, urgent measures to combat air pollutants, particularly O3, CO, SO2, and PM10, are critical for protecting public health.