Growing impact of air pollution on health

In 2014, researchers from Queensland University in Australia said heathy individuals who commute by bike in car traffic don’t show initial signs of increased health risks due to air pollution, but they still recommended that bike commuters try to minimize exposure to exhaust.

Even as an eighth grader running along the frontage roads of Southfield Freeway in Detroit, I wondered about the air I was breathing and if exercising in it would do me harm.

Nearly 40 years later, as I run or bike along the eight lanes of traffic of the Cooper River bridge, I still have questions and concerns.

From a national perspective, it seems like we hear more about health studies on coffee, chocolate and red wine than we do air pollution, which seems to make headlines only in extreme situations, such as the blackened skies of Beijing.

Yet the World Health Organization estimates that 8 million people die prematurely each year from causes associated with both outdoor and indoor air pollution.

As I make weekly perusals of current studies posted by the U.S. National Library of Medicine and the National Institutes of Health, the ones on air pollution flag my attention. And there are certainly more studies on the subject than the ones than make national wires.

In the past two months, here are some highlights from what researchers have revealed.

The news can be a mixed bag, but last week one large, long-term study in Denmark’s largest cities, Copenhagen and Arhus, indicated that the health benefits of exercise outweigh the potential harm of air pollution. The risks posed by obesity and physical inactivity are worse than those from exposure to pollution.

But researchers added caution should be used.

The study included more than 52,000 adults between the ages of 50 and 65 years old. In 1993 and 1997, the participants reported on their outdoor physical activity levels. The researchers estimated the participants’ exposure to air pollution based on traffic levels at their home addresses.

By 2010, 5,500 of the participants had died. Among them, there were 20 percent fewer deaths among those who exercised than among those who were inactive.

“Even for those living in the most polluted areas of Copenhagen, it is healthier to go for a run, a walk or to cycle to work than it is to stay inactive,” says Zorana Jovanovic Andersen, an associate professor at the university’s Center for Epidemiology and Screening, in a university news release.

“However, we would still advise people to exercise and cycle in green areas, parks, woods, with low air pollution and away from busy roads, when possible.”

One caveat to the study is that this was Denmark. Andersen added the findings may not hold true in cities with significantly higher air pollution levels.

The study was published in the March issue of the journal Environmental Health Perspectives.

As spring allergies leave many of us sneezing and sniffling, it may not come as a surprise that certain air pollutants may boost the potency of tree pollen.

In laboratory tests and computer simulations, German researchers found that two pollutants — ozone and nitrogen dioxide — have a significant effect on birch pollen, called Bet v 1. Specifically, these pollutants appear to provoke chemical changes in the pollen that seem to raise its potency.

Levels of both ozone and nitrogen dioxide are also tied to climate change, according Ulrich Poschl of the Max Planck Institute in Germany. The finding, in combination with climate change, might help explain why airborne allergies are becoming more common.

The research is still in the early stages and was scheduled to be presented at an annual meeting of the American Chemical Society in Denver.

About 50 million people in the United States have nasal allergies and the number is increasing, according to the American College of Allergy, Asthma and Immunology.

Also in March, researchers published a study of cardiovascular screening tests of more than 300,000 people in New York, New Jersey and Connecticut.

The study, presented March 16 at the annual meeting of the American College of Cardiology and appearing in the Journal of the American College of Cardiology, indicates that high levels of small-particle air pollution can increase the risk for narrowing of the carotid arteries, located in the neck, and may raise your risk for stroke.

The carotid arteries deliver blood to the brain. Fine particulate matter — particles of pollution smaller than 2.5 micrometers in diameter — is the most common type of air pollution and comes from sources such as car exhaust and the burning of wood or coal.

Those who lived in areas with the highest levels of air pollution were 24 percent more likely to have narrowing of the carotid arteries than those in areas with the lowest levels of air pollution.

“Our study adds to the growing body of evidence that air pollution is a significant risk factor for cardiovascular disease,” said lead author Dr. Jonathan Newman, a cardiologist at New York University’s Langone Medical Center in New York City, in a release.

“It shows that a person’s cardiovascular risk is not only associated with their genes, health behaviors and lifestyle choices, it also depends to some extent on the world we live in and the air we breathe.”

Newman said those at greatest risk are the very young, very old and those with other medical problems. People in good health in most parts of the United States do not face a significant health risk.

He added that the results draw attention to the importance of reducing air pollution.

Ever wonder what you’re breathing when stuck in traffic or at stoplight?

In February, British researchers at University of Surrey found that drivers are exposed to very high levels of air pollution, specifically nanoparticles, when they stop at red lights.

The pollutants are tied to increased risk of lung and heart diseases.

The study found that at red lights, peak nanoparticle exposure was 29 times higher than when the cars were in free-flowing traffic.

“Our time spent traveling in cars has remained fairly constant during the past decade despite the efforts to reduce it,” says study author Prashant Kumar in a release. “With more cars than ever joining the roads, we are being exposed to increasing levels of air pollution as we undertake our daily commutes.”

Kumar said that drivers should be aware of the risks and limit exposure by keeping windows shut and fans off, as well as increasing the distance between cars as much as possible.

As for pedestrians, Kumar says they should consider paths less dependent on traffic light crossings.

Reach David Quick at 937-5516.