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Several recent studies have found that constant exposure to high levels of air pollution has negative effects on the brain. The last post described negative effects on the gray matter in brains (resulting in smaller brain volumes) of elderly women from air pollution, but this study found negative effects (lower grade point averages) in young children from high air pollution. From Environmental Health News:

Bad air means lower grade point averages in Texas

Fourth and fifth graders in El Paso, Texas, are more likely to have lower grade point averages if heavily exposed to contaminated air at home, according to a new study.It bolsters a growing body of evidence that air pollution can impair success in school.

They found that for all types of air pollution sources, more exposure corresponded with lower grade point averages. Only one type of pollution—point sources such as factories—was not significantly linked to lower grade point averages.University of Texas at El Paso researchers analyzed the grade point averages of 1,895 children and, using their home location, estimated their exposure to air toxics—such as benzene, arsenic, lead, mercury, hydrochloric acid, toluene, vinyl bromide, xylenes, and diesel particulate matter—using federal data.

“Effects appear to be insidious, since they are mild, unlikely to be perceived, and, hence, unlikely to be addressed in any way … seemingly trivial effects on children’s development may translate into substantial impacts throughout the life course in terms of physical and mental health and personal success,” the authors wrote.The researchers did control for some other things that can affect children’s grades such as poverty, mother’s age, education and ability to speak English, and the child’s race and sex.

Still, the study doesn’t prove that dirty air makes kids do worse in school. It does, however, suggest children’s developing bodies are more susceptible to air pollution, which can harm their respiratory systems and brain.Air pollution might hamper kids’ grades via two primary ways: Illnesses, mostly respiratory, that would make them miss school, and developmental problems resulting from long-term exposure, said Sara Grineski, an associate professor of sociology at The University of Texas at El Paso and co-author of the new study.

Others have found similar links between air pollution and academic performance. Three months ago Columbia University's Perera and colleagues reported that New York City children born to mothers in poverty and exposed to certain air toxics during pregnancy had lower IQs.  Perera, tracking the mothers and children since before birth, said the pollution exposure prior to birth is more strongly linked to learning and behavioral problems. 

In the current study it’s unclear if the children were exposed in their mothers’ womb—an exposure window that is critical to brain development, Perera said....Other studies support this—in February Calderón-Garcidueñas and colleagues reported Mexico City smog was linked to impaired short-term memory and IQ in children.

The city is more than 80 percent Hispanic....Previous studies have shown that El Paso’s minorities are disproportionately impacted by toxics, Grineski said. The city of 675,000 is one of the worst when it comes to particulate matter—a mix of substances emitted by combustion sources, including cars, trucks, industrial plants and wood burning—especially coarse particulates, PM10, those between 2.5 and 10 micrometers (from about 25 to 100 times thinner than a human hair, according to the EPA). El Paso’s 24-hour PM10 average is about 233 micrograms per cubic meter of air, according to the latest EPA data from 2013, which was eighth highest among more than 500 U.S. cities. El Paso, along with Laredo, has the highest carbon monoxide levels in Texas.

Two related stories that look at children, exercise, and academic performance. Boys, in general, have higher activity levels than girls, and they need exercise and recess to be able to get through the rest of the school day. Sitting quietly in class and doing classwork is hard when one has lots of excess energy. In fact, sitting still for hours on end is NOT healthy in any way for anyone! Fidget, fidget, fidget... From Science Daily:

High levels of physical activity linked to better academic performance in boys

Higher levels of physical activity are related to better academic achievement during the first three school years, particularly in boys, research shows. For instance, boys with higher levels of physical activity, and especially walking and bicycling to and from school, had better reading skills than less active boys....The findings of the present study highlight the potential of physical activity during recess and participation in organized sports in the improvement of academic achievement in children

 Instead of medicine, why aren't doctors prescibing exercise? From The Atlantic:

Exercise Is ADHD Medication

Physical movement improves mental focus, memory, and cognitive flexibility; new research shows just how critical it is to academic performance.

...More insipid but also more clearly critical to addressing what's being called the ADHD epidemic is plain old physical activity.

This morning the medical journal Pediatrics published research that found kids who took part in a regular physical activity program showed important enhancement of cognitive performance and brain function. The findings, according to University of Illinois professor Charles Hillman and colleagues, "demonstrate a causal effect of a physical program on executive control, and provide support for physical activity for improving childhood cognition and brain health." If it seems odd that this is something that still needs support, that's because it is odd, yes. Physical activity is clearly a high, high-yield investment for all kids, but especially those attentive or hyperactive. This brand of research is still published and written about as though it were a novel finding, in part because exercise programs for kids remain underfunded and underprioritized in many school curricula, even though exercise is clearly integral to maximizing the utility of time spent in class.

Earlier this month, another study found that a 12-week exercise program improved math and reading test scores in all kids, but especially in those with signs of ADHD.

Last year a very similar study in the Journal of Attention Disorders found that just 26 minutes of daily physical activity for eight weeks significantly allayed ADHD symptoms in grade-school kids. The modest conclusion of the study was that "physical activity shows promise for addressing ADHD symptoms in young children." 

"If physical activity is established as an effective intervention for ADHD," they continued, "it will also be important to address possible complementary effects of physical activity and existing treatment strategies ..." Which is a kind of phenomenal degree of reservation compared to the haste with which millions of kids have been introduced to amphetamines and other stimulants to address said ADHD. The number of prescriptions increased from 34.8 to 48.4 million between 2007 and 2011 alone. The pharmaceutical market around the disorder has grown to several billion dollars in recent years while school exercise initiatives have enjoyed no such spoils of entrepreneurialism. 

Over all, the pandemic of physical inactivity, as Hillman and colleagues put it in their Pediatrics journal article today, is "a serious threat to global health" responsible for around 10 percent of premature deaths from noncommincable diseases. 

John Ratey, an associate professor of psychiatry at Harvard, suggests that people think of exercise as medication for ADHD. Even very light physical activity improves mood and cognitive performance by triggering the brain to release dopamine and serotonin, similar to the way that stimulant medications like Adderall do