Air Pollution Now Strongly Linked to Mental Problems

Worldwide, 93% of children live in areas with air pollution at levels above World Health Organization (WHO) guidelines.¹ Further, more than 1 in 4 deaths among children under 5 years is related to environmental risks, including air pollution.

When most people think about health risks linked to polluted air, respiratory issues come to mind and, indeed, in 2016 ambient (outside) and household air pollution contributed to respiratory tract infections that led to 543,000 deaths in children under 5.² However, air pollution takes a toll on the whole body, contributing not only to physical risks but also mental health problems.

A set of studies by researchers at Cincinnati Children’s Hospital, in collaboration with researchers at the University of Cincinnati, has highlighted the risks to children, in particular, who may see their mental health suffer as a result of polluted air.

Three Studies Link Air Pollution to Mental Health Risks

In the first study, published in Environmental Health Perspectives, researchers looked at the association between emergency room visits and exposure to fine particulate matter (PM 2.5), which refers to dust, dirt, soot and smoke particles smaller than 2.5 micrometers in diameter.³

The WHO report revealed that in low- and middle-income countries, 98% of children under 5 years are exposed to fine particulate matter at levels higher than the WHO air quality guidelines.

The Environmental Health Perspectives study revealed that short-term exposure to air pollution was linked to increased utilization of the Cincinnati Children’s emergency department for psychiatric issues, particularly for adjustment disorder and suicidality.

Further, mental health of children living in high-poverty neighborhoods was most affected by air pollution. Lead study author Cole Brokamp, Ph.D., with Cincinnati Children’s Hospital, said in a news release:⁴

“This study is the first to show an association between daily outdoor air pollution levels and increased symptoms of psychiatric disorders, like anxiety and suicidality, in children. More research is needed to confirm these findings, but it could lead to new prevention strategies for children experiencing symptoms related to a psychiatric disorder.”

Air Pollution May Cause Brain Inflammation, Anxiety Symptoms

The second study, published in the August 2019 issue of Environmental Research, looked into exposure to traffic-related air pollution (TRAP) on brain metabolism and symptoms of generalized anxiety in 12-year-olds.⁵ Recent exposure to TRAP was associated with generalized anxiety symptoms and increased myo-inositol, a marker of inflammation in the brain.

“This is the first study of children to utilize neuroimaging to link TRAP exposure, metabolite dysregulation in the brain, and generalized anxiety symptoms among otherwise healthy children,” the researchers concluded. “TRAP may elicit atypical excitatory neurotransmission and glial inflammatory responses leading to increased metabolite levels and subsequent anxiety symptoms.”⁶

The third study, also published in Environmental Research, found that early-life exposure to TRAP, as well as exposure during childhood, was significantly associated with depression and anxiety symptoms in 12-year-olds.⁷ A similar association between air pollution and mental health was previously reported among adults, but this study suggests the effects may also occur in children exposed to air pollution.

“Collectively, these studies contribute to the growing body of evidence that exposure to air pollution during early life and childhood may contribute to depression, anxiety, and other mental health problems in adolescence,” Patrick Ryan, Ph.D., a lead author of the Environmental Health Perspectives study, said in a news release. “More research is needed to replicate these findings and uncover underlying mechanisms for these associations.”⁸

Past research has also found that living in an area with higher levels of air pollution is associated with decreased cognitive function and sleep disturbances.⁹

“Evidence that exposure to air pollution affects brain structure was found by magnetic resonance imaging (MRI) of participants in the Framingham Offspring Study, indicating that higher exposure to PM2.5 is associated with a reduction in total brain volume,” according to a Royal College of Physicians report.¹⁰

Why Children Are Especially Vulnerable to Air Pollution

When children are exposed to pollutants, they’re even more vulnerable than adults, in part because their bodies (including their lungs and brains) are still developing, putting them at risk from inflammation and other health damage. They also have a longer life expectancy, giving more time for diseases to emerge.

According to WHO, a combination of “behavioral, environmental and physiological factors” makes children particularly susceptible to air pollution, adding:¹¹

“[Children] breathe faster than adults, taking in more air and, with it, more pollutants. Children live closer to the ground, where some pollutants reach peak concentrations. They may spend much time outside, playing and engaging in physical activity in potentially polluted air.

Newborn and infant children, meanwhile, spend most of their time indoors, where they are more susceptible to household air pollution, as they are near their mothers while the latter cook with polluting fuels and devices … In the womb, they are vulnerable to their mothers’ exposure to pollutants. Exposure before conception can also impose latent risks on the fetus.”

Exposure to air pollution has also been linked to problems with fetal brain growth.¹² The WHO report analyzed studies published within the past 10 years, and used input from dozens of experts, to reveal some of the top health risks air pollution poses to children. Among them:¹³

Air Pollution Interferes With Sleep

Research presented at the American Thoracic Society (ATS) 2017 International Conference suggested poor air quality may also disrupt your sleep.¹⁴

People in the top quarter of NO2 exposure (nitrogen dioxide, which is traffic-related air pollution) were 60% more likely to have low sleep efficiency over a five-year period compared to those in the lowest quarter. Among those exposed to the highest levels of fine particle pollution, there was a 50% increased likelihood of low sleep efficiency.

The researchers suggested the effect could be related to air pollution’s effects on the “central nervous system and brain areas associated with breathing control and sleep.”¹⁵

Sleep, in turn, is intricately linked to mental health, so one way air pollution may contribute to mental health symptoms could be by disturbing sleep. Meanwhile, previous research suggests that children with mood disorders or negative emotional symptoms may be more vulnerable to the harms of air pollution exposure.¹⁶

In other words, among people with poorer mental health, air pollution may lead to greater physical risks, including higher heart rate and blood pressure, and lower lung function, compared to those with better mental health.¹⁷ Mental illness could therefore potentially determine a population at increased risk of adverse health effects from air pollution.

Agriculture Is a Major Source of Air Pollution

The majority of global airborne particulate pollution — 85% — comes from fuel combustion, with coal being the “world’s most polluting fossil fuel.”¹⁸ Even in the U.S., an estimated 200,000 premature deaths are caused by combustion emissions, including that from vehicles and power generation.¹⁹

However, research published in the journal Geophysical Research Letters demonstrated that in certain densely populated areas, emissions from farming far outweigh other sources of particulate matter air pollution.²⁰ The study found that in Europe, the eastern U.S. and China, agriculture is a significant source of PM2.5.²¹ Further:²²

“In the past 70 years, global ammonia emissions have more than doubled, from 23 Tg/yr to 60 Tg/yr. This increase is entirely attributed to NH3 [ammonia] emissions from agriculture, with N fertilizer use contributing 33% and livestock production 66%. The emissions from livestock production come from animal houses and storage systems, animal manure, and grazing.”

Ammonia is one of the byproducts of fertilizer and animal waste. When the ammonia in the atmosphere reaches industrial areas, it combines with pollution from diesel and petroleum combustion, creating microparticles. Concentrated animal feeding operation (CAFO) workers and neighboring residents alike report higher incidence of asthma, headaches, eye irritation and nausea.

Research published in the American Journal of Respiratory and Critical Care Medicine also revealed that markers of lung function were related to how far they lived from CAFOs.²³

Protecting Yourself From Polluted Air

Air pollution poses a silent yet insidious threat to human health, one that can be difficult to get away from depending on where you live and work. WHO, in fact, reported that only 8% of people worldwide are breathing air that meets their standards.²⁴

One important step is to fortify your body with anti-inflammatory vegetables and fats, which may help to protect you from some of the damage air pollution causes. Notable standouts include:²⁵

• Omega-3 fats — They’re anti-inflammatory, and in a study of 29 middle-aged people, taking an animal-based omega-3 fat supplement reduced some of the adverse effects to heart health and lipid levels, including triglycerides, that occurred with exposure to air pollution (olive oil did not have the same effect).²⁶
• Broccoli sprouts — Broccoli-sprout extract was shown to prevent the allergic nasal response that occurs upon exposure to particles in diesel exhaust, such that the researchers suggested broccoli or broccoli sprouts could have a protective effect on air pollution’s role in allergic disease and asthma.²⁷ A broccoli-sprout beverage even enhanced the detoxification of some airborne pollutants among residents of a highly-polluted region of China.²⁸
• Vitamins C and E — Among children with asthma, antioxidant supplementation including vitamins C and E helped to buffer the impact of ozone exposure on their small airways.²⁹
• B vitamins — A small-scale human trial found high doses of vitamins B6, B9 and B12 in combination completely offset damage caused by very fine particulate matter in air pollution. Four weeks of high-dose supplementation reduced genetic damage in 10 gene locations by 28% to 76%, protected mitochondrial DNA from the harmful effects of pollution, and even helped repair some of the genetic damage.³⁰

Tending to the quality of your home’s indoor air is also important, since most people spend the majority of their time inside. In fact, not only do Americans spend about 90% of their time indoors, but some pollutants may be two to five times more concentrated indoors than out.³¹ One commonsense measure is to simply open your windows to let fresh air in.

Installing an attic fan can also help bring fresh air into your home while installing kitchen and bathroom fans that vent to the outside can help remove contaminants from these rooms. The following steps will further help to improve your indoor air quality: