Assessment of air quality in the Aburrá Valley (Colombia) using composite indices: Towards comprehensive sustainable development planning

This article aims to assess the air quality in the Aburrá Valley using a composite air quality index (CAQIAV). A multi-criteria methodology is used for the construction of the index, consisting of a framework for the selection, standardization, weighting, and aggregation of indicators. The proposed methodology generated three monthly and annual values of CAQIAV that differ based on the threshold used for data normalization: Unhealthy (level of alertness), Unhealthy for Sensitive Groups (level of prevention), and National Standard thresholds. The analysis of the PM10 subindex (AQIsubPM10) and PM2.5 subindex (AQIsubPM2.5) was similarly performed monthly and annually. The results show that AQIsubPM10 performs better than AQIsubPM2.5 in annual and monthly terms, indicating that the pollution in the Aburrá Valley is mainly anthropogenic. Nevertheless, in the most critical months (February and March), government policies should not focus solely on restricting the mobility of private vehicles, since this mobile source only contributes 2.7% of the PM2.5 particles in the Aburrá Valley. Moreover, in these months, several natural phenomena hinder the dispersion of air pollutants due to the morphological and climatic conditions of the valley. In conclusion, this study recommends the implementation of a CAQIAV based on the Unhealthy for Sensitive Groups threshold as it avoids putting the health of citizens at risk, especially for those belonging to sensitive groups. Likewise, several guidelines and solutions are proposed to configure a comprehensive sustainable development policy in the Aburrá Valley.