Particulate Matter and Associated Metals: A Link with Neurotoxicity and Mental Health

Abstract

Particulate air pollution (PM) is a mixture of heterogenous components from natural and anthropogenic sources and contributes to a variety of serious illnesses, including neurological and behavioral effects, as well as millions of premature deaths. Ultrafine (PM0.1) and fine-size ambient particles (PM2.5) can enter the circulatory system and cross the blood–brain barrier or enter through the optic nerve, and then upregulate inflammatory markers and increase reactive oxygen species (ROS) in the brain. Toxic and neurotoxic metals such as manganese (Mn), zinc (Zn), lead (Pb), copper (Cu), nickel (Ni), and barium (Ba) can adsorb to the PM surface and potentially contribute to the neurotoxic effects associated with PM exposure. Epidemiological studies have shown a negative relationship between exposure to PM-associated Mn and neurodevelopment amongst children, as well as impaired dexterity in the elderly. Inhaled PM-associated Cu has also been shown to impair motor performance and alter basal ganglia in schoolchildren. This paper provides a brief review of the epidemiological and toxicological studies published over the last five years concerning inhaled PM, PM-relevant metals, neurobiology, and mental health outcomes. Given the growing interest in mental health and the fact that 91% of the world’s population is considered to be exposed to unhealthy air, more research on PM and PM-associated metals and neurological health is needed for future policy decisions and strategic interventions to prevent public harm.

The oxidative potential of particulate matter (PM) in different regions around the world and its relation to air pollution sources

“…Exposure to particulate matter (PM) has been associated with millions of premature deaths each year worldwide. 1–3 According to numerous studies, particulate matter is responsible for a multitude of adverse health risks, including cardiovascular disorders, 4–7 impaired mental health, 8–10 carcinogenic diseases and respiratory problems. 11–15 Due to the considerable differences in chemical composition of ambient particles formed from different emission sources, the PM mass concentration is probably not an ideal measure for the toxicity of PM.…”

Influence of Meteorological Conditions and Fire Hotspots on PM0.1 in Northern Thailand during Strong Haze Episodes and Carbonaceous Aerosol Characterization

“…However, ultrafine particles or nanoparticles (PM0.1) has recently become of more concern, because they are more carcinogenic and can cause greater health effect than larger particles because of larger surface area (Sharma and Balasubramanian, 2018;Ajdary et al, 2018;Schraufnagel, 2020). Besides traveling deep into the lung mainly in the alveolar region (Schraufnagel, 2020), PM0.1 can translocate from the cardiopulmonary system to the central nervous system by crossing the blood-brain barrier, and potentially cause brain damage (Cheng etal., 2016;Jew et al, 2019;Morris-Schaffer et al, 2019;Hahad et al, 2020;Potter et al, 2021).…”

The Role of Fossil Fuel Combustion Metals in PM2.5 Air Pollution Health Associations

“…For example, PM 2.5 inhalation study in mice found that PM 2.5 -bound metals could reach and gather in secondary off-target tissues (liver, heart and brain) [155]. After intratracheal instillation of mice with coal and coal fly-ash, Cr, Fe and Ni were detected in liver, spleen and brain [156] PM and associated metals have been linked to neurotoxicity and mental health [157]. Excess brain exposure to either essential or non-essential elements can result in brain dyshomeostasis, which has been implicated in both neurodevelopmental disorders (NDDs; autism spectrum disorder, schizophrenia, and attention deficit hyperactivity disorder) and neurodegenerative diseases [158].…”