Neurological and respiratory outcomes of the HIPTox controlled double-blind air pollution exposure trial

Abstract Air pollution, particularly particulate matter (PM), is a well-established risk factor for cardiopulmonary disease, but its impact on brain health remains underexplored. This double-blind clinical trial investigated acute cognitive and respiratory responses to common PM-containing pollutant mixtures. Fifteen healthy volunteers ( ≥ 50 years, family history of dementia) undertook 60-minute exposures to woodsmoke, diesel exhaust, cooking emissions, limonene secondary organic aerosol (SOA), and clean air (control), separated by ≥2-weeks. Pre- and post-exposure assessments evaluated cognitive and respiratory function. Pollutant source significantly influenced cognition: diesel exhaust and woodsmoke improved processing speed; limonene SOA enhanced working memory compared to cooking emissions; and diesel exhaust may impair executive function. Forced Expiratory Volume in 1 second percentage predicted was lower following woodsmoke and limonene SOA versus clean air. Specific pollutant sources acutely influenced cognition and lung function, with responses varying by source. This approach can guide focused mitigation strategies to protect both respiratory and neurological health.