The impact of air pollution on cognitive function

Faherty, Thomas B. S. ORCID: 0000-0003-4064-9034 (2022). The impact of air pollution on cognitive function. University of Birmingham. Ph.D.

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Abstract

The impact of air pollution (AP) on cognitive function is widely understudied. Currently, most evidence focuses on correlating chronic AP exposure to performance on off-the-shelf cognitive tests in children and ageing participants. This thesis aimed to investigate the impact of both acute and chronic AP exposure on attention, socio-emotional processing, and episodic memory in clinically health adult populations using specially designed behavioural tasks. Using both experimental and quasi-experimental methods, participants were exposed to AP from a range of sources including Particulate Matter (PM) through candle burning; Traffic-related Air Pollution (TRAP) through quasi-experimental measurements during commuting; and Diesel Exhaust (DE) though the use of an atmosphere chamber. Participants in all studies were clinically healthy adults aged between 18 and 50 with no history of cardiovascular or neurological disease. Results indicated a reduction in pro-social behaviour 24 hours following acute exposure to PM and TRAP and lower cognitive control 4 hours following acute exposure to DE. Critically, no immediate effect of acute AP exposure was identified on these functions. The delay between exposure and cognitive dysfunction is suggestive of inflammatory mechanisms as a likely explanation for the identified effects. An immediate deficit in spatiotemporal encoding ability following acute TRAP exposure was identified, suggestive of hypoxia as a mechanistic explanation. However, no episodic encoding difficulties were identified after PM or DE exposure, nor any effect of any AP species on recall ability. This suggests that episodic memory is preserved despite the identified socio-emotional and executive deficits. Chronic exposure was quantified using participant residential postcodes throughout the lifetime. Higher chronic AP exposure was associated with lower cognitive control, indicative of neurodegeneration or stunted neurodevelopment. Together, the findings highlight an impact of AP on the quality and ease of decision making, emotional control, and learning of new information. These processes are critical to successfully navigate the complex ever-changing human environment, and degradation of these processes could lead to risk-taking, aggression, and degradation of mental health.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):