Exposure to air pollution is fueling fluctuations in mood among many Americans, but precisely how these emotional responses take shape varies greatly from individual to individual, a new study has found.
Inhalation of airborne contaminants can cause day-to-day disruptions in "affect," or mood — increasing long-term risk of adverse mental health outcomes and also reducing climate action, according to the study, published Wednesday in PLoS ONE.
Humans' sensitivities to environmental hazards, including the impacts on their moods, play a critical role in their overall vulnerability to the impacts of climate change, noted the authors, led by researchers at Stanford University.
As climate-related physical and mental health threats continue to surge worldwide, the researchers sought to measure the ways in which pollution-related mood swings impact overall vulnerability.
Building on known links between air pollution and mental health issues, the authors proposed what they call the "affective sensitivity to air pollution" construct, informed by robust and long-term datasets.
Specifically, they applied statistical models to intensive, repeated measures of mood obtained from 150 U.S. individuals for more than a year.
The researchers then evaluated two branches of the "affective state" of these participants: arousal, the level of physiological activation, and valence, the positive or negative nature of their mood.
Ultimately, the authors found that the affect arousal of those included in the study trended lower than usual on days with excess air pollution. However, they also identified substantial differences among the individual participants.
The researchers additionally determined that affective sensitivity could in part explain one of the mechanisms by which air pollution exposure raises longer-term risk of anxiety and depression.
Meanwhile, they also observed that when air pollution blunts an individual's mood, that impact could be associated with a lack of climate action.
With these results in mind, the authors stressed a need to incorporate the pollution-mood connection into climate adaptation planning. Doing so, they argued, could help inform both climate vulnerability assessments and personalized interventions.
"This new construct can be leveraged to better integrate affect and mental health in climate adaptation policies, plans, and programs," they concluded.
