Single-centre, double-blind clinical trial, 15 healthy volunteers, ≥50 years old with a family history of dementia, undertook four 60-minute controlled exposures to PM-containing pollution mixtures: woodsmoke, diesel exhaust, cooking emissions, and limonene secondary organic aerosol (SOA), and clean air as a control. Each exposure was separated by ≥2-weeks as a washout, and medical oversight was available throughout. Pre- and post-exposure assessments measured respiratory function via spirometry and evaluated cognitive functions including processing speed, executive function, working memory, socio-emotional cognition, and motor control.