Air pollution by PM2.5 in Morelia, Michoacán

Abstract

In this study, air pollution by suspended PM_2.5 particles in the city of Morelia, Michoacán, Mexico was analyzed. Non-parametric analysis of variance (ANOVA), correlation and regression methods were carried out to evaluate the relationship between PM_2.5 with carbon monoxide (CO), ozone (O₃) and PM_2.5 recorded at two monitoring sites in Morelia, and 1 in the Metropolitan Zone of Mexico City. In general terms, the center of Morelia predominated with high concentrations of PM_2.5 compared to those observed in the Enes-UNAM, Morelia campus and the Merced station in the center of Mexico City. Likewise, PM_2.5 pollution in Morelia increased 53% from the period 2015-2023; the months with the greatest increase were January, February and March 2023 with 84%, 65% and 106% respectively.

Also, the historical increase of 46 days above the official Mexican standard NOM-025-SSA1-2021 is reported, which establishes a limit of 41µg/m³ of PM_2.5 as a daily average, of which 8 days were consecutive, especially in May 2023 due in part to agricultural burning and forest fires that occurred on the outskirts of Morelia. But the number of days was due to the change from the previous value of 45µg/m³ regulated in NOM-025-SSA1-2014.

Keywords

Suspended particles PM₁₀, PM_2.5, carbon monoxide, ozone, agricultural burning