When you think of climate change, what are the first few pictures and thoughts that pop into your mind? Melted ice caps, animal extinctions, polluted cities? You would be right to consider these ideas. After all, climate change is an all-encompassing issue. It’s less likely that you associated climate change with its effect on the human brain. The effect of air pollution, as realized by pollutants like polycyclic aromatic hydrocarbons (PAHs), alone plays a huge role in how the human brain (and body) develops.
PAHs comprise a family of 1000 air pollutants, many of which are cytotoxic, carcinogenic, and mutagenic. That is, these agents are highly destructive to cells, cancerous, and capable of genetic mutation within the human body. Nevertheless, they are widespread in Earth’s atmosphere and poorly regulated. Indeed, they are found everywhere, such as in gasoline-and diesel-using vehicles, coal, and space heaters. Disturbingly, PAHs are reproductive toxins and neurotoxicants that are able to cross the placenta and damage the fetal brain, yielding serious, dangerous and irreversible effects. Many involve a “decrease in motor activity, neuro-muscular, physiologic and autonomic abnormalities and decreased responsiveness to sensory stimuli” (Perera et al., 2008). And, according to one of the largest Magnetic Resonance Imaging (MRI) studies on these elements, prenatal exposure causes a “subsequent reduction of the white matter surface in childhood” (Peterson et al., 2015), predominantly in the left hemisphere of the brain. This contact has great impacts on the frontal, parietal and temporal lobes, which all help to regulate attention and control and are crucial in intelligence; a Chinese study of the effects of PAHs noted that mothers who lived in environments with high levels of air pollution had greater cord blood levels of PAH-DNA and lower levels of abrineurin or Brain Derived Neurotrophic Factor, an important protein for brain growth and development. A similar study done in Mexico City reached similar findings (Perera, 2017).
The Environmental Protection Agency indicated that, in 2021, over 68 million tons of air pollutants were emitted into the atmosphere. The U.S. and many other countries have taken action to decrease air pollution and climate change, but they remain troublesome, as evidenced, for instance, in the above discussion of PAHs. While air pollution levels have generally decreased across the globe, urban air pollution is still on the rise. To prevent further catastrophic damage to our health and the neurodevelopment of future generations, we must urgently pursue solutions to all agents of climate change. In doing so, it is imperative that we start addressing the issue from a biological and psychological perspective.
Perera, F.P (2017). Multiple Threats to Child Health from Fossil Fuel Combustion: Impacts of Air Pollution and Climate Change. Environmental Health Perspectives, 125(2).https://doi.org/10.1289/EHP299
Peterson BS, Rauh VA, Bansal R, et al. (2015). Effects of Prenatal Exposure to Air Pollutants (Polycyclic Aromatic Hydrocarbons) on the Development of Brain White Matter, Cognition, and Behavior in Later Childhood. JAMA Psychiatry. 72(6), 531–540. doi:10.1001/jamapsychiatry.2015.57
Perera, F., Li,T., Zhou, Z., Yuan, T., Chen, Y., Qu,L., Rauh, V.A.,, Zhang, Y., & Tang, D. (2008). Benefits of Reducing Prenatal Exposure to Coal-Burning Pollutants to Children’s Neurodevelopment in China. Environmental Health Perspectives, 116(10)https://doi.org/10.1289/ehp.11480