Short-term PM2.5 exposure and executive function: association and neurophysiological mechanisms

Abstract

Introduction: Although converging evidence has shown that exposure to PM2.5 caused adverse effects on brain structure and cognitive function, the association between the short-term exposure to PM2.5 and cognition dysfunction remain underexplored, especially possible neurophysiological mechanisms. Methods: We conducted a longitudinal observational study with four repeated measurement sessions among 90 young adults from September 2020 to June 2021. During each measurement session, we measured participants’ personal level air pollution exposure for one week with portable monitors, followed by executive function assessment and electrophysiological signals recordings at the assessment center. Standard Stroop color-word test was used accompanied with electrophysiological recordings to assess performance on executive function. Results: Adjusted mixed-effect models demonstrated that elevated PM2.5 exposure three days prior to cognitive assessment (lag 3) was associated with (1) declined performance in both congruent and incongruent tasks in Stroop tests, (2) reduced lower alpha event-related desynchronization (ERD) during 500-1000 ms after stimuli, both indicating impaired executive control. No associations were found between short-term PM2.5 exposure and aperiodic exponents both in tonic and phasic state, residual periodic alpha oscillation in tonic state. Conclusion: Our results provided evidence that short-term PM2.5 exposure was associated with brain executive dysfunction. Reduced alpha ERD was likely to be the underlying pathway through which PM2.5 induced adverse effects on neuron activities during cognitive tasks. This study implies that transcranial electric stimulation and transcranial magnetic stimulation could be applied to access cortical neuron excitability to compensate for the cognitive impairment caused by PM2.5 exposure.