Could air pollution cause strokes?

Research suggests a link between the two
Published: Nov. 18, 2022 at 10:56 PM CST
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NEW ORLEANS (WVUE) - Everyday conveniences people rely on like driving, taking a bus or airplane, and even cooking contribute to air pollution. And now research suggests there is a link between air pollutants and stroke.

Professor Charles Miller, Ph.D., is a toxicologist at Tulane University’s School of Public Health. He spoke to FOX 8 about modern life and pollution.

“Right, our life that we live makes us more prone to pollution, we need energy and things like that and as a side effect that’s pollution,” said Miller.

Under the federal Clean Act, the EPA sets air quality standards for six common pollutants: carbon monoxide, lead, nitrogen dioxide, sulfur dioxide, ozone, and particle pollution which is also called particulate matter.

Humans are not impervious to pollution.

“The air pollution that’s studied most, it largely is a diffusion process, so particles or the chemicals come in and they simply spread out in the body, so air pollution from a bus or things like that can eventually wind up in all the tissues of your body,” said Miller.

And studies show a link between pollution and stroke.

Dr. Sheryl Martin-Schild is a vascular neurologist at LCMC Health and medical director at the certified stroke centers at Touro Infirmary and New Orleans East Hospital.

She explained what a stroke involves.

“A stroke is when there’s part of the brain that is injured because of disruption in blood flow,” said Schild. “It can happen because a clot travels to the brain, obstructs an artery, and blocks the flow to some part of the brain or it can happen when there is a narrowing such that the amount of flow eventually becomes compromised or it can be from when there is a broken blood vessel with bleeding into the brain.”

And research published in the Journal of Stroke says, “Evidence from epidemiological studies have demonstrated a strong association between air pollution and cardiovascular diseases including stroke.”

There are other studies suggesting the same.

Research published in 2021 in the Journal Lancet states that “The risk for ischaemic stroke is increased after short-term or long-term exposure to air pollution.”

That is a stroke that occurs when blood clots or other particles block blood vessels in the brain, according to the CDC.

Dr. Schild was asked about the notion of pollution contributing to the onset of a stroke.

“There are studies that support that the air we breathe can impact our risk of having [a] stroke but these are epidemiological studies which are limited in their ability to demonstrate causality,” she said.

Still, is it feasible that the body could be impacted in such a way due to air pollution?

“Yes, so the smallest particle that we breathe, too small for us to see with our eyes, and the oxygen and the gasses that we breathe that we can’t possibly see make it into the deep parts of our lung where oxygen exchange happens,” said Schild. “So these toxic particles can cross into our bloodstream and then trigger the cascade of inflammation and platelets becoming activated and sticking together which is the first part of most clots.”

Miller was also asked about the plausibility of a pollution-stroke connection,

“Oh certainly, yes, it’s clear. It happens. In this country, it’s not as prevalent as in lots of other countries though because like I was saying we’ve done a lot to reduce our emissions that were really bad in the seventies,” he said.

Still, the CDC and the National Center for Environmental Health wrote, “Particle pollution has been linked to heart attacks and strokes, and even death in people with heart disease.”

Miller was asked about that conclusion.

“People who are more susceptible, who have existing health problems are the most sensitive to these types of air pollutants,” he said.

Helen Balser lives in St. Bernard Parish and thinks the pollution-stroke connection is possible.

“It’s not impossible I would say because you know there’s, look at the plants around here with all that smoke and everything coming out,” she said.

Mary Hampton, a St. John Parish resident, lives near an industrial plant and believes there is a correlation between pollution and health problems, including stroke.

“We have all of this going on, we have a lot of cancer in this area especially this street right here, we have a lot of cancer, but we’ve had strokes,” said Hampton.

Louisiana is part of the so-called “Stroke Belt”, eleven states that have excess stroke mortality. Around Louisiana, there are air monitoring stations.

Jason Meyers is the administrator of air planning and assessment for the La. Department of Environmental Quality.

He was asked if Louisiana has an air pollution problem sufficient to pose risks to humans.

“We monitor for toxic air pollution, toxic, air toxics as well and we, we do not see anything that approaches a standard,” Meyers said.

But sometimes communities can slip out of EPA compliance related to certain emissions.

“We have two areas of the state that are not in attainment. One is St. Bernard Parish,” said Meyers. The other is just a portion of Evangeline Parish.”

Attainment means an area meets National Ambient Air Quality Standards.

“Both of those areas are non-attainment for SO2,” said Meyers. “However, we’re working with the facilities in those areas to bring those areas back into attainment.”

SO2 is sulfur dioxide, a colorless gas with a pungent odor.

He said the agency wants to reduce problematic emissions wherever they occur.

“LDEQ’S goal is always to minimize emissions and keep them as low as possible,” said Meyers.

Recently, the EPA announced grants funded by the Inflation Reduction Act and the American Rescue Plan for Louisiana totaling nearly $3 million. DEQ’s share is over $900, 000 from those grants.

DEQ welcomes the funding.

“Obviously, we could use more resources, more resources would always be good, however, as part of the American Rescue Plan we did receive two grants recently to do additional monitoring,” said Meyers.

Many communities sit near interstate systems and vehicles emit pollution.

Schild suggests people living near busy highways take that into consideration when planning outdoor activities.

“When it comes to air pollution try to minimize your time around peak emissions like during traffic time and try to take your nice exercise and walks during the evening after the peak traffic time has died down,” she said.

Miller said, “If I spent an hour in that environment, you know, the air pollution would be greater there.”

But, in terms of pollution, it is not limited to just outside air.

“There’s mold that’s in our home, there’s things like dust mites, there’s all kinds of chemicals that are in the household dust,” said Miller.

He held a portable air sampling meter as he participates in a Tulane study on indoor pollution.

We’re trying to get a better idea about what that exposure is in your home because everybody’s home is different,” said Miller.

Of course, there are many long-known risk factors for stroke that have nothing to do with pollution.

“Like having high blood pressure, diabetes, smoking, obesity, heart rhythm problems, and then there are the organs that become injured that ultimately lead to the stroke, for example, the heart. The structure or function of the heart can be compromised, the rhythm of the heart can be compromised, or you can have obstruction to the blood vessels due to the development of atherosclerosis,” Schild stated.

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