Lung Deposition of Particulate Matter as a Source of Metal Exposure: A Threat to Humans and Animals

The deposition of particulate matter (PM) in the lungs is a health problem that primarily affects individuals working in mines and other highly polluted environments. People living in large cities also accumulate PM in their lungs throughout their lives due to the high levels of air pollution often observed in urban environments. In addition to the direct effects that the physical deposition of PM causes in the lungs, such as increased levels of inflammation and fibrosis, these pollutants can be associated with additional toxic effects, including genotoxicity and other molecular, cellular, and systemic alterations that can lead to the development of multiple diseases. This occurs because PM carries a number of toxic pollutants to the lungs, especially metals and metalloids such as arsenic, lead, cadmium, chromium, and mercury. Although the histopathological effects of occupational (pneumoconiosis) or environmental (anthracosis) deposition of PM in the human lungs are well described, little is discussed about how these morphological alterations can be a proxy for acute and chronic exposure to several toxic metals. Furthermore, the effects of PM-metal complexes on the health of animals, especially those living in urban environments, are often overlooked. In this context, this narrative review aims to discuss the impacts of lung-deposited PM-metal complexes on the health of multiple species, highlighting the broad effects caused by air pollution. Using the One Health approach, this article examines how environmental issues impact the health of both humans and animals.