Air Pollution and Childhood Brain Development

The impact of air pollution on general health is well-known. The Centers for Disease Control (CDC) indicate that airborne contaminants such as ground-level ozone and particulate matter such as dirt, soot, and smoke increase the likelihood of developing:

  • Lung cancer
  • Cardiovascular disease
  • Asthma
  • Pneumonia
  • Bronchitis

In addition, exposure to ground-level ozone and particulate matter is associated with:

  • Increased emergency room visits
  • Aggravation of asthma, emphysema, and bronchitis symptoms
  • Impaired lung development in children
  • Low infant birth weight
  • Early death related to lung and heart disease

Air pollution affects everyone on the planet. However, the negative effects of air pollution have an increased impact on the following groups:

  • Infants
  • Children
  • The elderly
  • Pregnant women
  • People in areas of high population density

To date, the majority of research identifies the problems caused by air pollution as physiological. Research shows air pollution is primarily associated with cardiovascular disease, i.e. issues with the lungs and/or heart. However, a study published early in 2019 connects increased exposure to air pollution with dementia and cognitive decline in adults.

This is an issue of concern for everyone.

In addition, the results of a recent study published recently by researchers in Spain may trigger a greater concern in the general public. The study found that exposure to air pollution during gestation and infancy can have a negative impact on the fundamental cognitive abilities of developing children.

The BREATH Project

We’re slightly understating the relevance of the Spanish study. It’s a significant development in our understanding of the effect of air pollution on child brain development.  The BREATH Project was the first study of its kind. Health scientists examined developmental markers related to several areas of cognition in 2,221 children ages 7-10 in and around Barcelona, Spain. They then compared the results of the cognitive tests to levels of air pollution the children were exposed to while in utero and at key points during their early development. In the words of the lead scientists on the study, The BREATH Project is “…one of the largest conducted on the impact of air pollution on cognitive development in children.”

It’s important on levels. First, it underscores the importance of the progress we’ve made over the past fifty years with regards to air pollution. We’ve come a long way. And if we’re serious about our ongoing health and wellness, we still have more work to do. Second, it begins to connect the dots between environmental factors and mental health. While the study does not attempt to determine a causal relationship between pollution and mental health, the identification of the impact of air pollution on brain development lays the groundwork for future scientists to pose this question:

Is there a connection between exposure to air pollution and mental health?

But we’re ahead of ourselves.

That’s the future.

For now, we’ll have a look at what the data from the BREATH Project says.

The Effect of Air Pollution on Cognition: The Results

Scientists found that exposure to air pollution in utero, immediately after birth, and between ages 4-7 is associated with negative outcomes for the following cognitive measures:

Working Memory

Working memory is also called short-term memory. This system controls the temporary storage and management of information required to perform complex tasks. The working memory system keeps track of information relevant to any ongoing task. It’s similar to what most of us understand as the working memory on our computers. It keeps all the bits and pieces of information at the ready for our use in the moment. Working memory is essential to tasks such as learning, reasoning, comprehension, and language development. Any impairment of working memory can negatively impact the ability to think logically. It also affects our ability to understand what we experience and form long-term memories based on our experiences.

Attentiveness

Attentiveness, or attention, is the “state of awareness in which the senses are focused exclusively and selectively on aspects of the environment.” Environmental stimuli that can catch and maintain attention have properties such as novelty, movement, repetition, contrast, and intensity. In practical terms, our attentional capacity – our attentiveness – plays a large role in our ability to focus our minds on one thing in favor of another. Attentiveness allows us to narrow the myriad stimuli we experience every moment to what’s important. It’s essential for all higher cognitive functioning. Therefore, any impairment in attention or attentiveness can negatively impact the ability to focus, learn, and complete tasks of any sort, from the minor to the major.

The Conflict Network

Also known as the executive function or executive control network, this system of neurons manages, resolves, and reconciles the simultaneous presence of two or more stimuli, concepts, or ideas that are incompatible, at variance, or clash with one another. We’re not talking about social skills, here – that’s interpersonal conflict resolution. Instead, we’re talking about the ability of the brain to identify and choose the best of several opposing options. The conflict network detects errors and eliminates cognitive obstacles that impede the successful completion of a given task. Additionally, it plays a role in the regulation of daily thoughts and feelings. Any impairment in the conflict network can negatively impact the ability to resolve ambiguities, maintain concentration, and complete mental or physical tasks.

Perhaps now you understand why we got ahead of ourselves, above. The data begs us to pose questions about the relationship between air pollution and mental health. If exposure to air pollution has a negative impact on the brain systems responsible for advanced learning and higher-order thinking, then there may be additional downstream consequences researchers have yet to identify.

Air Quality, Environment, and Behavioral Health

The BREATH Project focused solely on foundational neurodevelopmental milestones related to working memory, attention, and the conflict network. Their study was unique in that it tracked children from birth and analyzed the effect of exposure to air pollution – at key developmental stages – on their performance on computer-designed, skills-based cognitive tests. They concluded that:

“Exposure to air pollutants during childhood jeopardizes the achievement of full neurodevelopmental potential and diminishes mental capital at the population level.”

This conclusion and supporting data invites health scientists around the world to explore the connection between air pollution and a range of neurological, developmental, and behavioral disorders. It also reinforces the need to maintain an environment that supports the healthy development of our children and enables them to reach their full potential. The study makes it clear: clean air helps us maintain optimal population-level mental capital, while polluted air reduces the cognitive abilities essential for optimal mental functioning. This information is critical to consider as we move forward and expand our understanding of how our environment affects our physical, psychological, and emotional health.