The association of particulate matter PM2.5 and nitrogen oxides from ambient air pollution and mental health of children and young adults- a systematic review

Abstract Introduction The developing brain, especially vulnerable during neuroplastic phases, is influenced by environmental and genetic factors. Understanding the impacts of air pollution on children’s and young adults’ mental health is an emerging research field. Content This review systematically examines the adverse associations of ambient air pollutants on mental health. A database search using Scopus, EMBASE, Global Health, and PsycINFO included articles from 2013 onwards, following PRISMA guidelines. Of the 787 identified articles, 62 met the inclusion criteria. Quality was assessed using the EPHPP tool, and Best Evidence Synthesis (BES) evaluated the findings. Summary The review found 36 associations between ambient air pollutants and adverse mental health outcomes across seven life-course exposure periods. Strong evidence linked early-life PM2.5 and NO2 exposures to Autism Spectrum Disorder (ASD) and childhood exposures to Attention Deficit Hyperactivity Disorder (ADHD). Significant, though inconsistent, associations were found between air pollutants and cognitive impairments, anxiety, depression, self-harm, and other behavioral problems. The heterogeneity of exposure limits and lack of experimental studies hinder causal assessment. Outlook Compelling evidence links early-life and childhood exposure to PM2.5 and NO2 with ASD and ADHD. These findings highlight the need for public health policy changes and further research to explore these associations comprehensively.