Clean air captures attention whereas pollution distracts: evidence from brain activities

Awareness of the adverse impact of air pollution on attention-related performance such as learning and driving is rapidly growing. However, there is still little known about the underlying neurocognitive mechanisms. Using an adapted dot-probe task paradigm and event-related potential (ERP) technique, we investigated how visual stimuli of air pollution influence the attentional allocation process. Participants were required to make responses to the onset of a target presented at the left or right visual field. The probable location of the target was forewarned by a cue (pollution or clean air images), appearing at either the target location (attention-holding trials) or the opposite location (attention-shifting trials). Behavioral measures showed that when cued by pollution images, subjects had higher response accuracy in attention-shifting trials. ERP analysis results revealed that after the cue onset, pollution images evoked lower N300 amplitudes, indicating less attention-capturing effects of dirty air. After the target onset, pollution cues were correlated with the higher P300 amplitudes in attention-holding trials but lower amplitudes in attention-shifting trials. It indicates that after visual exposure to air pollution, people need more neurocognitive resources to maintain attention but less effort to shift attention away. The findings provide the first neuroscientific evidence for the distracting effect of air pollution. We conclude with several practical implications and suggest the ERP technique as a promising tool to understand human responses to environmental stressors.