Recent exposure to air pollution and its effect on cognitive and mental health: A citizen science panel study in Barcelona

BACKGROUND AND AIM: The association between recent exposure to air pollution and cognitive and mental health has not been thoroughly investigated so far. We conducted a panel study co-designed with citizens to assess whether air pollution can affect attention processes and self-perceived stress and mood. METHODS: From September 2020 to January 2021, we followed 290 adults (mean age = 37.9 years; standard deviation = 12.2 years) for 14 days in Barcelona, Spain. Two tasks were self-administered daily through a mobile application: the Stroop color-word test to assess attention performance and a set of 0-to-10 rating scale questions to evaluate well-being (sad to happy), energy (asleep to active) and stress (low to high). From the Stroop test, three outcomes were calculated and z-score-transformed: cognitive speed, cognitive throughput and inhibitory control. Air pollution was assessed using the mean nitrogen dioxide (NO₂) concentrations (mean of all Barcelona monitoring stations) 24 hours before the tasks were completed. We applied conditional linear regression using participant as strata to estimate intra-individual associations, controlling for day of the week and time-varying factors such as alcohol consumption and physical activity. Also, we tested the interaction effect of the presence of natural (green and blue) spaces within 300 m from the residence. RESULTS:Repeated attention test performances (n = 2,971) of the participants reflected lower cognitive throughput (β -0.02, p = 0.04) with a recent increase of 10 μg/m³ exposure to NO₂. This association was stronger (β -0.05, p = 0.02) when participants were not residing close to natural spaces. We did not find significant associations with cognitive speed, inhibitory control, well-being, energy and perceived stress. CONCLUSIONS:Our findings suggested that short-term exposure to air pollution has a negative effect on attention performance. This effect may be modified by the presence of natural spaces. KEYWORDS: Air pollution, citizen science, attention processes, mental health, observational panel study