Associations between Indoor Pollutants, Neurodevelopmental, Oncological, and Respiratory Health Risks, and Vulnerable Populations: A Systematic Review

People spend most of their lives indoors, where pollutant exposures often exceed outdoor levels. This systematic review synthesizes evidence on indoor pollutants, biological mechanisms, and associated health outcomes, with a focus on vulnerable populations. Using PRISMA-guided selection, 15 studies were analyzed across epidemiology, toxicology, and mechanistic research. Findings indicate strong associations between indoor pollutants—including particulate matter, volatile organic compounds, heavy metals, pesticides, flame retardants, and polycyclic aromatic hydrocarbons—and neurodevelopmental impairments, cancer-related risks, and respiratory disease. Mechanistic pathways include oxidative stress, neuroinflammation, endocrine disruption, and epigenetic changes. Pregnant women, fetuses, and children are disproportionately affected. Interventions such as ventilation improvements, low-emission building materials, and equity-focused policies are urgently needed. This review underscores the importance of designing healthy and climate-resilient indoor environments to safeguard public health.