Acute Diesel Exhaust Exposure Causes a Delayed Reduction in Cognitive Control

Abstract

Urban residents are frequently exposed to high levels of traffic-derived air pollution for short time periods, often (but not exclusively) during commuting. Although chronic air pollution exposure and health effects, including neurological effects on children and older adults, are known to be correlated, causal effects of acute pollution exposure on brain function in healthy young adults remain sparsely investigated. Neuroinflammatory accounts suggest effects could be delayed by several hours and could affect attention, especially in social contexts. Using a controlled atmosphere chamber, we exposed 81 healthy young adults to either diluted diesel exhaust (equivalent to polluted roadside environments) or clean air for one hour. Half of each group immediately completed a selective attention task to assess cognitive control; remaining participants completed the task after a 4-hour delay. Cognitive control was significantly poorer after diesel versus clean air exposure for those in the delay but not immediate test condition, suggesting an inflammatory basis for this acute negative effect of air pollution on cognition. These findings provide the first experimental evidence that acute diesel exposure, comparable to polluted city streets, causes a negative effect on cognitive control several hours later. These findings may explain commuter mental fatigue and support clean-air initiatives.

HIPTox—Hazard Identification Platform to Assess the Health Impacts from Indoor and Outdoor Air Pollutant Exposures, through Mechanistic Toxicology: A Single-Centre Double-Blind Human Exposure Trial Protocol

“…Based on effect size and variance from a currently unpublished study [ 35 ] looking at cognitive load and attention (measured as change in response time ( RT) after Diesel Exhaust exposure ( RT = 22 ms, s.d. = 25 ms), a sample size of 30 subjects will have 90% power to detect significant response time changes of 15 ms assuming the standard significance level of p < 0.05.…”