Metal Pollution in the Air and Its Effects on Vulnerable Populations: A Narrative Review

Particulate atmospheric pollution poses a global threat to human health. Metals enter the body through inhalation attached to these particles. Certain vulnerable groups are more susceptible to toxicity because of age, physiological changes, and chronic and metabolic diseases and also workers because of high and cumulative exposure to metals. A narrative review was conducted to examine the effects of key metals-arsenic, cadmium, chromium, copper, lead, mercury, manganese, nickel, vanadium, and zinc-on vulnerable populations, analyzing articles published over the past decade. Some of these metals are essential for humans; however, excessive levels are toxic. Other non-essential metals are highly toxic. Shared mechanisms of toxicity include competing with other minerals, oxidative stress and inflammation, and interacting with proteins and enzymes. Prenatal and childhood exposures are particularly concerning because they can interfere with neurodevelopment and have been associated with epigenetic changes that have long-term effects. Occupational exposure has been studied, but current exposure limits for specific metals appear dangerous, emphasizing the need to revise these standards. Older adults, pregnant women, and individuals with metabolic diseases are among the least studied groups in this review, underscoring the need for more research to understand these populations better and create effective public health policies.