How air quality affects asthma

ALana Yañez’s severe asthma had been completely under control for years. But when the 2020 wildfires began sending thick clouds of unsightly black smoke into the Southern California sky, the 41-year-old Los Angeles resident began to gasp.

She felt her chest tighten and then become painful. Yañez closed all the windows in his home, turned on the air conditioning and turned on an air filter. But these measures barely affected her symptoms.

“I sucked on my inhaler every two hours,” says Yañez, adding that regardless of the medications he was given, the chest pain persisted.

After several miserable days, Yañez remembered that he had always breathed better on the coast. When she checked local air quality maps, she saw that the air was much cleaner near the ocean. So she packed up her job and her son and headed to Redondo Beach.

“With every mile, my lungs got better,” she says. “When I went out to the beach, I was able to breathe without pain.”

While dirty air—whether from diesel exhaust, traffic fumes, industrial pollution, or wildfires—can make it difficult for anyone to breathe, it hits people with severe asthma much harder, with some ending up in the emergency room or even hospitalized.

During the spring and summer of 2023, when wildfires in Canada sent thick clouds of smoke into the air, emergency room visits associated with asthma in the US rose 17% above what would normally be expected.

The research linking air pollution exposure to asthma attacks “is very consistent,” says Dr. Akhgar Ghassabian, associate professor of pediatrics and population health at NYU Grossman School of Medicine. Even low levels of exposure can trigger an exacerbation, she says, and the groups most at risk are children and the elderly.

See more information: What to know about the latest advances in treating severe asthma

How does dirty air harm the respiratory system and worsen asthma?

For the past few decades, volunteers, one at a time, have entered a small chamber in a University of North Carolina laboratory and pedaled a stationary bike or sat calmly while components of diesel exhaust or burning wood smoke were pumped into the air. inside. the room.

Volunteers were carefully selected to avoid serious reactions. They were all relatively young, under 45, and generally healthy, although some had mild asthma. After a few hours in the chamber, study participants gave sputum samples, which helped researchers identify those who were sensitive to the vapors and exactly how their airways and lungs were being affected.

Early experiments by researchers at UNC and the U.S. Environmental Protection Agency (EPA) looked at the impact of exposure to diesel exhaust components, which included fine particles (PM2.5), ozone and other gases. In some volunteers, the vapors triggered increases in airway inflammation, says Dr. David Peden, senior associate dean for translational research and medical director of the Center for Environmental Medicine, Asthma and Lung Biology at the University of North Carolina School of Medicine. .

“Our studies are designed to get a sense of the underlying biology and to use that information and those methods to identify specific interventions,” says Peden. Inhalation of exhaust constituents caused neutrophilic and eosinophilic inflammation. “The most important thing we’ve found with most air pollution is that it irritates the airway epithelium.”

Most people will experience some degree of airway inflammation when they encounter air pollution or wildfire smoke, says Peden. “For many, it is simply a hassle and they may not worry about it,” she adds.

But for those with severe asthma, the impact can be much greater, says Peden. This is especially true for children: their respiratory rates tend to be higher than those of adults, so even a small amount of polluted air can have a big impact.

The center’s most recent research has focused on potential treatments for exposure to pollution and wildfire smoke in volunteers considered sensitive. It produced promising results. For example, people who produce excess mucus in response to dirty air may be helped by inhaling hypertonic saline. “When they inhale the solution, the mucus loosens,” explains Peden.

Research has also suggested a role for a certain type of vitamin D (gamma-tocopherol) that appears to calm eosinophils’ response to pollution. But, cautions Peden, “this is a very early phase study. It’s not definitive.”

Ongoing research is examining the genetics that impact sensitivity to wildfire smoke and air pollution, as well as ways to protect people with respiratory illnesses, such as studies to determine the effectiveness of N95 masks.

See more information: An N95 mask is your best outdoor defense against wildfire smoke

The impact of dirty air on people with severe asthma

Exposure to any type of dirty air can make asthma much worse, says Dr. Stokes Peebles, chief of the allergy and immunology section at Vanderbilt University Medical Center. “It can cause a feeling of tightness in the chest, coughing and shortness of breath,” he says. “The fine particles, PM2.5, can reach the lowest parts of the airways.”

These ultrafine particles can also penetrate deep into the lungs, says Dr. Barbara Mann, associate professor of medicine in the division of pulmonary, critical care and sleep medicine at the Icahn School of Medicine and Mount Sinai in New York City. “They can evade most of the body’s defenses and wreak havoc.”

Air pollution can cause two problems in the airways: constriction and inflammation. And it doesn’t stop there, says Mann. The smallest particles can penetrate the bloodstream and cause systemic inflammation. The more severe a person’s asthma was at the start of the study, the lower the dose of polluted air needed to trigger an exacerbation and the worse these flare-ups could be.

Wildfire Smoke: An Urgent Danger

Smoke from wildfires is an especially problematic type of air pollution. This “outperforms other types of air pollution,” says Mann. “It’s a toxic mixture of organic and inorganic materials that have been burned.”

As Peden points out, wildfires can significantly increase the amount of fine particles in the atmosphere. “In 2018, when the bonfire was burning, the amount of fine particles in San Francisco increased three to five times,” he says.

Unlike air pollution related to industry and traffic, wildfire smoke is also likely to contain fumes from the burning of man-made items such as homes and vehicles. This could be an ominous combination.

See more information: What wildfire smoke does to the human body

New asthma triggered by air pollution

Along with asthma exacerbation, air pollution can trigger new-onset airway disease in those who are exposed, says Matt Perzanowski, associate professor of environmental health sciences at Columbia University’s Mailman School of Public Health.

Additionally, studies conducted at Columbia have shown that when people are exposed to diesel smoke, they can develop allergies to proteins that they were not previously allergic to. “We studied kids in the South Bronx,” says Perzanowski. “When they are exposed to cockroaches and diesel exhaust, they are more likely to develop a cockroach allergy.”

Perzanowski recommends that parents limit their children’s exposure to pollution, especially smoke from wildfires.

How to protect yourself

If you have asthma, the most important step you can take to avoid an exacerbation due to wildfire smoke and pollution is to check your local air quality reports daily. “There is good data available in real time,” says Ghassabian. AirNow.govfor example, it’s an excellent resource.

On days with poor air quality, take precautions to protect yourself from exposure to dirty air. These are doctors’ favorite strategies: