Memory under siege: the cognitive costs of smoking and vaping.

Memory function is critically essential across all life stages, yet it is increasingly compromised by exposure to airborne pollutants due to human behaviours. This review examines the adverse impacts of tobacco smoke and e-cigarette vapour on memory function, emphasising the risks to younger populations. Both pollutants are potent oxidants that induce oxidative stress and inflammatory responses in the brain, leading to synaptic injury and neuronal apoptosis. These processes compromise neuronal integrity and function, potentially resulting in early-onset dementia. Additionally, third-hand exposure to tobacco smoke and e-cigarette vapour, through re-exposure to toxic chemicals on surfaces or clothing, poses significant risks, especially to toddlers. Epigenetic mechanisms, including DNA methylation and histone modification, further exacerbate these effects by altering gene expression critical for brain development and function. This review highlights the necessity for further research to develop risk-reduction strategies to protect cognitive health from these pollutants.