By Matt Sloane
WebMD Health News
Reviewed by Brunilda Nazario, MD
Nov. 10, 2014 -- On a bright, hot summer day in just about any major city in the world, there's a slightly yellowish haze that hangs in the air. It's the thing that makes sunsets appear fiery red, but it can be a dangerous health hazard for people living underneath. It's air pollution.
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Several recent studies link air pollution to all kinds of medical conditions, from autism to obesity. While we know pollution is bad for our lungs, research suggests that might be just the tip of the iceberg.
"In the area of air pollution, the maxim is 'the more you look, the more you find,'" says Norman H. Edelman, MD. He's the senior consultant for scientific affairs at the American Lung Association. "The more careful studies we do, the more [harmful] deleterious effects we find."
There are two types of air pollution: particulates and smog. Both can cause serious health effects.
"Particulates are the very fine particles, not the ones you can see," Edelman says, "and when particulate pollution goes up, there's a significant increase in hospital visits for people with heart and lung disease."
Particulate pollution largely comes from things like diesel exhaust, and wood-burning and coal-burning power plants, whereas smog or ozone is produced by smaller vehicle emissions.
The most recent study on the bad effects of pollution found that pregnant moms who were exposed to a type of pollutant called polycyclic aromatic hydrocarbons, or PAHs, were five times more likely to have children who developed ADHD.
Researchers think these toxins might change the wiring in an unborn baby's brain and increase their chances of having the behavior problems linked to ADHD.
A different study published just last month looked at the effects of two chemicals found in the air near some large factories and power plants: chromium and styrene. The researchers found that exposure seems to raise the risk of unborn babies getting autism in early childhood.
While those researchers also couldn't say exactly why this effect seemed to be present, they hope future research might shed some light.
Another pollution study in Spain followed 620 children through the age of 4. It found that those who'd been exposed in-utero to higher levels of two chemicals found in air pollution -- nitrogen dioxide and benzene -- had a 22% to 30% higher risk of poorer lung function in early childhood.
And in yet another highly concerning study, American researchers looked at more than 100,000 women over 25 years, and found that those who lived closest to major roadways were more likely to die suddenly from heart problems. They even suggested that living near a major road could be statistically as big of a contributing factor in sudden cardiac death as smoking or obesity.
"Air pollution is a very big deal," Edelman says. "Even though pollution levels are less than they were 20 years ago, it is still a very important contributor to poor health."
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"Those days when you can't see the downtown buildings, people with respiratory issues might need to use their inhaler more, might not sleep as well at night, depending on how much time they spent outside," Sheerin says.
"It's not necessarily making people run to the emergency room -- I think it just is aggravating baseline symptoms, so your control [of those symptoms] won't be as good."
Luckily, pollution numbers are on their way down. According to the Environmental Protection Agency, pollution levels have come down 62% since 1980 in the United States, despite the number of miles traveled by car increasing nearly 95%.
Worldwide, though, the picture is still somewhat grim, with more than 7 million deaths attributed to pollution in 2012, according to the World Health Organization. Edelman and the EPA agree more needs to be done.
Despite the risks, Edelman says, you can take steps to protect your health.
"In the summertime, when you get your local weather report, you usually also get a pollution report," he says. "If it's a high smog day, then you ought to stay indoors."
He also suggests you skip outdoor exercise on high-pollution days. If you have to go outside for extended periods of time, try to do it before traffic -- and pollution -- get bad.
Also, he says, eat right, exercise indoors if necessary, and if you have medication, take it as your doctor prescribed.
Sheerin says she warns her patients about cigarette smoke – something she considers to be an air pollutant.
"I think it's a disgusting habit, and I applaud places like The University of Georgia for banning it from campus."
High-Tech Project Show Promise
Some communities are getting creative with their pollution. A group of architects commissioned to build a garden in Geneva, Switzerland, installed their project in an unusual place: above a highway overpass.
The high-tech series of tubes, pumps, and solar panels traps carbon dioxide emissions from passing vehicles and, combined with sunlight, feeds an algae farm.
The resulting mass of algae can then be used to filter the air, for food products, cosmetics, or as fuel.
"The functioning and the placement of this bioreactor signals practices of the future: food production in an urban environment, the conservation of green space, and the reinterpretation of existing infrastructures," according a statement on the Cloud Collective's project web site.
While this system may work on a small scale, Edelman suggests that larger-scale support of pollution regulation will be the thing that helps us keep lowering pollution levels.
"We ought to support all of those regulations that increase required gasoline mileage in automobiles," he says, "and the less modern coal-fired power plants that are spewing out all of this particulate should be required to modernize. There are methods to substantially reduce the pollution from these plants."
Those two things, he says, could help reduce emissions, factory pollution, and the resulting health problems.
SOURCES: Norman H. Edelman, MD, pulmonologist; senior consultant for scientific affairs, American Lung Association. Kathleen Sheerin, MD, allergist, Atlanta Asthma and Allergy. Perera, F. PLOS One, November 2014. WebMD Health News from HealthDay: "Could Air Pollutants Raise a Child's Autism Risk?" Morales, E. Thorax, October 2014. Hart, J. Circulation, October 2014. Environmental Protection Agency Air Quality Trends. WebMD Health News: " Air Pollution Claimed 7 Million Lives in 2012: WHO." The Cloud Collective.
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