Air Pollution and Mental Health
The World Health Organization (WHO) describes pollution as the leading environmental cause of disease and premature death. Inhaled pollutants (e.g., nanoparticles, particulate matter and traffic-related pollution) are associated with wide-ranging adverse health outcomes, such as respiratory and cardiovascular morbidity and mortality, as well as diabetes, arthritis and gastrointestinal (GI) disease. Emerging evidence also indicates a relationship between ambient air and central nervous system (CNS) dysfunction. Although details have not been fully worked out, neurological and psychiatric disorders, including cognitive impairment, dementia, depression, bipolar, autism and Parkinson’s disease, have been linked to poor air quality. Our aim is to explore the impact of particulate matter (PM2.5 ) on the brain, with a particular focus on mechanisms leading to neuroinflammation and mental health disturbances. The impact of short- and long-term ambient air exposure will be examined along with the differential impact of air pollution on brain and behavior during diverse developmental stages. Sources of exacerbating and mitigating factors will be reviewed. The interaction between stress and poor air quality as a function of particulate matter (PM2.5) from the recent California fires is also a factor.
The World Health Organization (WHO) describes pollution as the leading environmental cause of disease and premature death. Inhaled pollutants (e.g., nanoparticles, particulate matter and traffic-related pollution) are associated with wide-ranging adverse health outcomes, such as respiratory and cardiovascular morbidity and mortality, as well as diabetes, arthritis and gastrointestinal (GI) disease. Emerging evidence also indicates a relationship between ambient air and central nervous system (CNS) dysfunction. Although details have not been fully worked out, neurological and psychiatric disorders, including cognitive impairment, dementia, depression, bipolar, autism and Parkinson’s disease, have been linked to poor air quality. Our aim is to review findings for air pollution and brain health throughout the lifespan, with a particular focus on underlying mechanisms and mitigating factors for its deleterious impact. We will also examine the interaction between stress and poor air quality, as well as the association of particulate matter PM2.5 from recent California fires with cortisol reactivity.
Although many air pollutants exist, research has largely focused on fine particulate matter when discussing the deleterious impact of ambient air on the brain. According to the EPA, fine particulate matter is defined as particles that are 2.5 micrometers in diameter, which is about 30 times smaller than the diameter of an average human hair, making the blood brain barrier vulnerable to these particles. Recent research has shown that exposure to PM2.5 can lead to oxidative stress and neuroinflammation in the central nervous system through various mechanisms such as the stimulation of microglia, which impacts pro-inflammatory cytokine elaboration, as well as via direct entry into brain through diffusion. Prolonged neuroinflammation has been linked to altered brain structures; for instance, studies have reported that urban residents show leaking capillaries, damaged perivascular glial sheets, and white matter lesions in the brain as well as explore the underlying mechanisms and outcomes of bad air.
Air pollution has been increasingly implicated in the development of pathologies related to the brain. Different age groups demonstrate unique risk factors leading to age-specific discrepancies in neurological outcomes. This review summarizes the patterns of brain-related disorders observed during the pre- and post-partum periods, early childhood, and adolescence as related to greater potential for ambient air-mediated insults during periods of heightened neuroplasticity. The impact of air pollution on aged individuals is also discussed in the context of this group's particular vulnerably to pollution-related brain toxicity. A number of additional lifestyle issues can exacerbate the deleterious impact of poor air quality on brain. For example, lower socioeconomic status, limited educational background, and high stress neighborhoods create heightened vulnerability to poor air quality on the cognitive impairments, underscoring the interactive effects of environmental variables and air pollution.
On a macro level, research has demonstrated that increasing the number of trees in urban settings improves air quality by helping remove air pollutants such as ozone and particulate matter. Trees have also shown to mitigate the stress caused by traffic sounds by acting as a natural barrier and redirecting the sounds. Although planting more trees is a simple intervention for combating the deleterious effects of air pollutants, research regarding interventions that can be accessible on an individual level remains sparse. Limited research has also shown that other measures, such as exercise and eating dark chocolate, may also help to combat the neuroinflammation brought on by exposure to air pollutants. Taking dietary supplements with antioxidant properties, such as vitamin E, also have been demonstrated to mitigate the deleterious effects of air pollution on brain. We will also explore various lifestyle-based interventions for reducing the harmful effects of air.