Sampling, composition, and biological effects of Mexico City airborne particulate matter from multiple periods

Air pollution is a worldwide environmental problem with an impact on human health. Particulate matter of ten micrometers or less aerodynamic diameter (PM₁₀) as well as its fine fraction (PM_2.5) is related to multiple pulmonary diseases. The impact of air pollution in Mexico City, and importantly, particulate matter has been studied and considered as a risk factor for two decades ago. Previous studies have reported the composition of Mexico City particulate matter, as well as the biological effects induced by this material. However, material collected and used in previous studies is a limited resource, and sampling and particle recovery techniques have been improved. In this study, we describe the methods used in our laboratory for Mexico City airborne particulate matter PM₁₀ and PM_2.5 sampling, considering the years 2017, 2018 and 2019. We also analyzed the PM₁₀ and PM_2.5 samples obtained to determine their composition. Finally, we exposed lung cell line cultures to PM₁₀ and PM_2.5 to evaluate the biological effect of the material in terms of cell viability, cell death, inflammatory response, and cytogenetic alterations. Our results showed that PM₁₀ composition includes inorganic, organic and biological compounds, while PM_2.5 is a mixture of more enriched organic compounds. PM₁₀ and PM_2.5 treatment in lung cells does not significantly impact cell viability/cell death. However, PM₁₀ and PM_2.5 increase the secretion levels of IL-6. Moreover, PM₁₀ as well as PM_2.5 induce cytogenetic alterations, such as micronuclei, anaphase bridges, trinucleated cells and apoptotic cells in lung cells. Our results update the evidence of the composition and biological effects of Mexico City particulate matter and provide us a reliable basis for future approaches.