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Residents of impoverished neighborhoods are exposed to higher levels of air pollution.
Although previous research has detailed a link between poverty and poor educational outcomes, researchers explored to what extent air pollution plays a role in this relationship.
Data show exposure to toxic air pollutants accounts for around one-third of reduced cognitive abilities exhibited by children living in poverty.
Children living in impoverished areas are exposed to increased levels of air pollution, which can lead to reduced cognitive abilities down the line.
That’s according to new research published Wednesday in the journal ScienceAdvances. Investigators explored the effects of early exposure to 50 pollutants known or suspected to harm the central nervous system. Data from 10,000 U.S. children were included in the analysis.
“Our findings suggest that children in poor neighborhoods are—disproportionately and with alarming frequency—poisoned by their environments from the moment they take their first breaths,” researchers wrote.
All children were born around 2001 and followed by researchers until they entered kindergarten. Researchers then assessed their early reading and math skills and compared findings based on neighborhood socioeconomic status and air pollution concentrations.
Exposure to pollutants during infancy reduced cognitive abilities measured at age 4 by about one-tenth of a standard deviation — equivalent to the learning loss that would typically occur after one month of missed elementary school.
Around one-third of the effect is a result of air quality disparities, while exposure to particulate matter, traffic-related pollutants, industrial-source heavy metals and several petrochemicals may have the most impact on cognitive abilities in early childhood. However, due to the difficulty of singling out effects of individual toxins, researchers urged caution when discussing the impacts of specific pollutants.
Although previous research has detailed an association between growing up in a poor neighborhood and diminished cognitive abilities and lower levels of educational attainment, authors set out to understand the mechanisms behind these effects.
Major roadways and other infrastructure are more likely to be located in, near or upwind of poor neighborhoods, disproportionately exposing these residents to air pollutants that can harm the central nervous system, they wrote.
In addition, young children are especially vulnerable to these pollutants as they breathe more air per unit of body weight, can absorb chemicals more efficiently and their biological systems are still developing.
Systemic racism, including historic redlining, also means racial minorities are more likely to live in impoverished areas and thus are more likely to breathe in harmful air pollutants. Studies have shown air pollution exposure is linked with decreased gray- and white-matter in the brain, suggesting air pollution could contribute to neurodegeneration.
Safety concerns and poor built environments may prevent more young children living in impoverished areas from spending time outdoors, but the older and more dilapidated housing in these areas could allow more outdoor air pollution to seep indoors through damaged windows or doors, according to the study published Wednesday.
One model included in the study details how some of the largest effects of neighborhood poverty were observed for toluene, a solvent added to gasoline; methanol, a solvent added to inks, resins, adhesives and dyes; carbon monoxide; and fine particulate matter.
However, exposure to air pollution is likely not the only way childhood poverty can affect cognitive development. Limited access to high-quality childcare and biological stress responses to local violence could also play a role, researchers say.
“Given that child cognitive skills predict many later life outcomes, such as higher earnings and better health in adulthood, our results suggest that environmental inequalities may contribute to the reproduction of poverty from one generation to the next,” authors wrote in the study, adding “environmental policy may also function indirectly as anti-poverty policy.”