Metagenomic analysis of bioaerosols (bacteria and fungi) associated with PM10 in the Mezquital Valley, Hidalgo, Mexico: Implications for public health

The Mezquital Valley (Hidalgo, Mexico) faces a severe environmental crisis driven by intense industrial activity and chronic wastewater pollution, factors historically associated with high rates of respiratory and gastrointestinal morbidity. This study assessed the integral biological quality of the air through monitoring and metagenomic profiling of bioaerosols physically associated with PM10 mass, using high-throughput sequencing of the 16 S rRNA gene (for bacteria) and Internal Transcribed Spacer (ITS) region (for fungi). The results revealed a high diversity of airborne microbiota with distinct taxonomic signatures reflecting a multi-source origin, including soil resuspension, hydro-aerosolization from contaminated water bodies, and industrial emissions. Multiple genera with significant pathogenic potential were identified, notably bacteria such as Clostridium and Pseudomonas, and fungi such as Aspergillus, Penicillium, Alternaria, and Cladosporium. The observed physical adhesion of inorganic particles to these biological propagules suggests a dangerous synergy; exposure to this complex mixture may enhance allergenicity and facilitate the deep penetration of pathogens into the respiratory system, thereby exacerbating health risks. These findings demonstrate that the airborne microbiome in industrial basins is a heterogeneous complex shaped by diverse local loads. Our study highlights the need for multifactorial environmental monitoring strategies that consider the interaction between chemical and biological agents to protect public health in the region. First metagenomic characterization of bioaerosols associated with PM10 in the highly polluted Tula Basin, Hidalgo, Mexico. Identification of high microbial diversity with multi-source origins, including soil resuspension, hydro-aerosolization, and industrial emissions. Detection of pathogenic (e.g., Clostridium, Pseudomonas, Aspergillus) and allergenic genera physically associated with airborne particles. The synergistic risk posed by inorganic pollutants (PM) and bioaerosols is well documented, amplifying the danger to public health. Site-specific biological profiles reveal a heterogeneous atmospheric microbiome influenced by local microenvironments. Findings call for integrating biological risks into Mexico’s environmental regulations (SEMARNAT) through multifactorial monitoring.