Tear Gas, Pollution, Wildfire Smoke: A Triple Threat to Your Lungs

Teron McGrew stayed home during the past two weeks while others in her hometown of Oakland were protesting systemic racism and police killings of black people. Like many of her neighbors, McGrew has asthma and, because of her breathing difficulties, she feared being exposed to COVID-19 and to tear gas used by police. She also feared police brutality.

The new coronavirus is taking a particularly cruel toll in minority communities, with black Americans far more likely to die from COVID-19 than white Americans. One of the inequities driving the high numbers of deaths is damage and disease to lungs caused by years spent breathing polluted air.

Lung health is a critical weapon in the fight to reduce deaths during the pandemic. Yet police have been firing chemicals at protesters that can damage lung cells. American soldiers exposed to tear gas in sealed chambers during annual combat training were shown in a 2014 study to be substantially more likely to contract acute respiratory infections afterward, prompting the Army to issue new rules that limit their exposure.

The respiratory onslaught precedes a wildfire season that further threatens to weaken immune protections against respiratory diseases such as COVID-19 and influenza.

“I’m an African American and I need to be in the protests against systemic racism, but I made a choice for my life,” said McGrew, a resident of North Oakland who works on issues of community and housing development. “I made a choice but people who are dying from COVID-19 and asthma and pollution, they don’t have a choice. They’re dying because of the inequalities and the systemic racism.”

Pollution from fossil fuels is also warming the planet and the region, leading to larger wildfires and more of their harmful smoke. As the coronavirus infects new victims, California is heading into a hot, dry wildfire season. Wildfire smoke can blanket forest and foothill communities and choke far-away cities with particles that penetrate lungs and weaken immune responses to infections.

The one-two punch of tear gas and wildfire smoke, coupled with ever-present air pollution from fossil fuels, is set to worsen suffering related to the coronavirus this year, with people of color living in polluted areas continuing to feel the worst effects.

Epidemiologists, geographers and other researchers have been learning in recent years that wildfire smoke poses a greater public health risk than previously realized. A new study from Montana shows exposure to “smoke waves” — multiple-day bouts of heavy smoke — led to a substantial increase in influenza cases the following winter.

“The literature shows that people who are exposed to air pollution during wildfires are more likely to get respiratory infections, and I would classify COVID-19 as a respiratory infection,” said Colleen Reid, a geographer at the University of Colorado, Boulder, whose research interests include health impacts from wildfire smoke. “It could lead to more severe cases or even more cases that are noticed.”

First Wildfire Smoke, Then Flu

To test the relationship between wildfire smoke and influenza, Erin Landguth, an associate professor at the University of Montana, led a study that examined health and smoke wave data over a decade from Montana. The study was published this month in the scientific journal Environment International.

Landguth’s team looked for impacts on flu cases within one to four weeks of a smoke wave, and they didn’t find a significant effect during that period. What has stunned experts were impacts on influenza cases detected months later, during the following winter.

“We thought there would be no way we’d see this long of a delay,” Landguth said.

Based on their analysis, the researchers concluded the epic 2017 wildfire season in Big Sky Country caused influenza cases that winter to at least double and possibly rise as much as fivefold.

Influenza kills tens of thousands of Americans every year, and the findings also have worrying implications for COVID-19 and other respiratory infections. Landguth is now gathering data from all Western states to expand the influenza research, and is also starting to investigate relationships between smoke waves and COVID-19 infections.

Michael Jerrett, a professor at UCLA’s Fielding School of Public Health, is among the scientists racing to understand relationships between various types of air pollution and COVID-19 as the disease continues to spread.

“You have to be cautious in interpreting what we’re finding, but I think what we’re seeing in a series of very rapidly developing studies is evidence that air pollution does make people more susceptible to COVID,” Jerret said. “The wildfires are likely to exacerbate the existing symptoms.”

More Smoke in California’s Future

The hazards are intensifying as warming temperatures, worsening droughts, overgrown forest understories, urban development and other changes intensify wildfire seasons, putting more smoke into the air and more smoke particles into lungs.

Led by scientists at Yale and Harvard, researchers several years ago used models of fire and winds to project smokier futures for Western counties as temperatures rise. Across the Bay Area, the density of smoke particles suspended in the air during an average smoke wave is projected to nearly double by 2050, compared with levels during the late aughts.

A wildfire outlook published by federal agencies on June 1 shows above normal potential for blazes across most of Northern California through September. Snowpacks are melting early in the warm spring temperatures, and hot and dry conditions are expected to persist.

The ingredient of greatest concern in smoke is PM2.5, the name given to the finest of particulate matter — particles so small they can lodge deep in lungs, and are sometimes so small they can enter the bloodstream. Smoke also affects levels of ozone pollution and it can contain toxic byproducts from incinerated plastics and paint.

Once inhaled, PM2.5 particles operate at a microscopic level to inflame and injure lung cells, providing the coronavirus and other pathogens with a boost as they work to overcome their victim’s immune system. The smoke also adds to risks of heart attack and a long list of other common and sometimes deadly maladies.

Tiny particulate matter isn’t just produced during wildfires — it’s present in pollution released by vehicle exhausts, power plants, refineries, farms and wood stoves.

Research is underway at Harvard and elsewhere examining whether exposure to tiny particulate matter from fossil fuel pollution increases the risk of death from COVID-19. If so, this would raise the already elevated coronavirus threats faced by communities of color, which are frequently located in less costly areas that are heavily polluted, including those along highways.

“Poor black and brown communities, especially, are at higher risk of dying from COVID, and they’re at higher risk because of a lot of things — one related to chronic inflammation from having faced chronic trauma and exposure, chronic air pollution, et cetera,” said Madhavi Dandu, a professor of medicine at UCSF.

“Many people in that setting are essential workers who don’t really have as much choice about whether they get to go to work,” Dandu said. “And a lot of people might live in closer housing settings or multigenerational households.”

Solutions, but Not Easy Ones

When smoke waves blot the skies, local governments and agencies often cancel classes and sporting and community events and recommend sheltering in place. For some in aging and inexpensively maintained housing, including rentals, however, the air in the home also becomes unsafe.

When Oakland fills with smoke from wildfires burning in the region, McGrew, the resident of North Oakland who suffers from asthma, says she’s forced indoors. “When the smoke was really heavy, that’s when I had to get my inhaler.”

During the 2016 and 2017 wildfire seasons, Shelly Miller, a professor of mechanical engineering at the University of Colorado, Boulder, led research that monitored indoor air quality in 28 homes of low-income residents in Denver.

“We were responding to an announcement we kept hearing on the news, which is, ‘It’s wildfire season, shelter in your home,'” Miller said. “And we kept thinking, ‘I don’t know if that’s always such a good idea,’ because many homes are not well protected from the outdoor environment, meaning lots of air can come inside from outside.”

Most of the occupants in the homes studied kept their windows open for cooling, and Miller’s team found PM2.5 levels could be much higher inside those homes during smoke waves than outside.

Running an air cleaner, also called an air purifier, has been found to be highly effective in reducing indoor pollution from wildfire smoke — particularly when it’s operated with windows closed.

The factors preventing many residents from buying air cleaners are the same as those forcing them to live in drafty homes in polluted areas — the impoverishing consequences of skyrocketing economic disparity and underinvestments in health and some urban areas.

In West Oakland, where air pollution from ships, trains and trucks at the port mixes with pollution from freeways and other sources, leading to high rates of asthma and other diseases, health care can be unaffordable, and the housing stock provides limited protection from pollution or smoke waves.

“Obamacare has helped, but people need to understand that most of our folks that don’t have resources don’t have health coverage,” said Ken Chambers, the pastor of the West Side Missionary Baptist Church in West Oakland, just a few blocks from the port’s fence line. “People who are poor and broke don’t have the availability to eat high quality foods, they’re eating fast foods. They don’t go to the doctor for regular routine checkups.”

McGrew, of North Oakland, has been trained to discuss climate change by the Climate Reality Project, a global nonprofit founded by Al Gore. She is also involved in Bay Area committees and efforts to tackle climate change.

She sees strong connections between racism, racial disparities and climate change, and she wants African Americans participating in decision-making that affects everything from how communities are policed to how to grow green jobs and slow warming by reducing fossil fuel use. Shifting from fossil fuels to cleaner economies also boosts air quality, improving lung health.

“For 400 years, African Americans have been left out of the equation,” she said. “We’ve got to be at the tables when policies are being drafted.”

Editor’s Note: KQED Science reporter Danielle Venton contributed to this story.

This story was produced through a partnership between KQED and Climate Central, a non-advocacy science and news group.