An overview of bioaerosols suspended in the atmosphere of metropolitan zone of toluca valley

Abstract

Particulate matter (PM) is recognized as a type of pollutant emitted through the air that generates adverse health effects. Bioaerosols are PM of biological origin, that has not been morphologically characterized as exhaustively as other types of PM. The term bioaerosols collectively refers to all dead or living airborne particles with biological origins, including pollen, fungi, bacteria, viruses, plant or animal debris, as well as fragments and products of pathogenic microorganisms. Pathogenic airborne microorganisms may have public health consequences. Bioaerosols suspended in ambient air from the Metropolitan Zone of Toluca Valley (MZTV), State of Mexico were identified by scanning electron microscopy followed by energy dispersive x-ray spectroscopy, to determine their morphology, elemental chemical composition, and average sizes. The bioaerosols detected were pollen, spores, microorganisms, fragments, and diatoms that exhibited diverse morphological structures; while some particles had rough or smooth surfaces, others were spongy and spherical or had irregular or thorny surfaces. Others, yet, had well-structured surfaces such as the amoeba that were detected in the study. EDS analyses carried out on SEM samples demonstrated that C and O were the main chemical elements of them. The main components of diatoms were the silicon and oxygen. The particle radii (r) of detected pollen was 2 µm ≤ r ≤ 23 µm, spores were 0.17 µm ≤ r ≤ 3.7 µm, microorganisms were 0.16 µm ≤ r ≤ 12 µm, and diatoms were 2.3 µm ≤ r ≤ 23 µm. Bioaerosols aerodynamic sizes range can be potentially poses adverse health effects.