Neurotoxic Metropolis: Navigating Inflammatory Risks to Brain Health in Urban Environmental Planning

Urban areas are epicentres of environmental stressors that pose significant risks to human health. Here, we highlight the manners in which these exposures—primarily air pollution, heat stress, and noise pollution—contribute to the development and progression of neurodegenerative conditions, such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis, through various inflammatory pathways. Airborne particulate matter can reach the brain directly and indirectly, triggering immune responses and altering brain structure. Heat stress exacerbates neuroinflammation and protein misfolding, while chronic noise exposure has been linked to increased dementia risk. Alarmingly, due to spatial disparities, low-income communities and People of Colour face disproportionately high exposure to these hazards. Mayors are not neurologists (frequently, the authors imagine), but they can help mitigate risk by adopting comprehensive climate and environmental policies informed by the Jemez Principles and integrated with environmental justice. Some proven efforts include implementing stricter industrial emission controls, deploying dense networks of air quality sensors, expanding urban green spaces, promoting alternative transportation, and enacting protective (i.e., equitable) zoning policies. While some cities have begun to implement such measures, results highlight the need for more aggressive and holistic approaches. As development and migration trends evolve and climate change accelerates, it is incumbent on mayors, city planners, policymakers, and public health officials to collaborate in creating healthier urban environments. These efforts should aim to mitigate the neurological impacts of environmental stressors and promote overall well-being for residents, with a particular focus on vulnerable populations. Neurological health is addressable by climate policy.