Air and Health Index (Mexico)

The guidelines for the first national Air Quality Index, the Air and Health Index (Índice AIRE y SALUD - IAyS), were established in NOM-172-SEMARNAT-2019, which came into effect in 2020. The main objective of this NOM was to standardize and provide a single method for obtaining an Air Quality Index for all cities and metropolitan areas in the country that have an atmospheric monitoring system. This NOM adopted a new indicator (NowCast) for particulate matter (PM10 and PM2.5) that aims to alert the public during high concentration events. In the case of ozone, the index was combined, reporting the highest category that reached the maximum of the hourly average or the 8-hour moving average.