California Wildfires

‘You can’t just hold your breath.’ Toxic smoke, fueled by wildfires, chokes California

FRESNO, Calif. — A new analysis of air quality in the United States clears up just how far smoke from wildfires burning in the western part of the nation can travel, as the fires continue to pose significant health risks to nearby communities. 

Wildfire smoke produced in the west reached as far east as Washington, D.C., and Philadelphia, increasing the number of smoky days in the east by 40 percent, according to an analysis released in September by NPR’s California Newsroom and Stanford University’s Environmental Change and Human Outcomes Lab. Researchers analyzed more than 10 years of data from the National Oceanic and Atmospheric Administration. 

While the smoke was dispersed widely, California communities closest to the wildfires have experienced high amounts of air pollution lasting for days in the past two months. In some cases, pollution indexes reached levels unlike any seen before, according to health and education officials who spoke to the PBS NewsHour. 

On Monday, an entirely different phenomenon overtook the skies in the San Joaquin Valley. A large dust storm visible from space swooshed through the Valley with winds of up to 40 miles per hour, leaving downed trees and small wildland fires in its wake, and lowering visibility to as low as a mile in some places.

The wind was part of a cold system that developed over the Pacific Northwest and brought some rain earlier on Oct. 8 but later weakened to a dry system. While it helped push out the smoke, winds picked up dust from fields and dry areas in the Valley from as far north as Sacramento down to Bakersfield — areas experts say are historically dry this year. 

The smoke and dust that has battered California in recent weeks comes after one of the hottest summers recorded, and as the state experiences extreme drought conditions. Before the dust storm, the National Weather Service’s Storm Prediction Center had raised the wildfire threat to “critical” in most of the Central Valley region of California due to the dry conditions. 


Orange skies fade the sun as smoke from nearby wildfires creates high levels of pollution in California’s San Joaquin Valley. Photo by Cresencio Rodriguez-Delgado/PBS NewsHour

“As long as we remain with no wetting rain that comes into the Valley, we’ll continue to see those dust storms with any dry system that comes through,” said Modesto Vasquez, meteorologist with the National Weather Service in Hanford, California.

Recent rain storms in the Sierra Nevada have helped slow the growth of the burning wildfires. For almost a month as the KNP Complex and Windy fires have raged in the Sierra Nevada, air pollution has fluctuated from dangerous particulate matter on some days, and clean blue skies on other days. Together, the fires have burned 185,000 acres as of this week. 

‘The worst I’ve seen it’

On a clean air day, the Sierra is visible to the east from any city or town in the Valley. But the smoke creates a wall that obscures the view of the mountains, turns the sky brown and gives the sun a locally infamous reddish hue. Flurries of ash fall like snowflakes onto the Valley, and within days will dust vehicles and street curbs. 

At first it’s just the sight of another wildfire nearby. But shortly after, patients begin to come in to see doctors. 

“The pollution is really so bad that you can literally feel like you are eating pollution,” said Dr. Malik Baz, an allergist and immunologist at the Baz Allergy, Asthma and Sinus Center in Fresno. “This is the worst that I’ve seen it.” 

Regular patients and new patients have come in through the start of the month with a litany of complaints: a cough, headache or burning sensations in their chest, eyes or nasal passages.

Baz, who has lived and worked in the Central Valley for 40 years, said there has been a roughly 20 to 30 percent uptick in patients in recent weeks, since smoke from wildfires began setting in. Across the Valley, the 14 Baz Allergy offices between Modesto and Visalia sometimes aren’t enough to help all the patients. Baz said there isn’t enough staff. 

“We are trying to see our own existing patients, and some other patients, but a lot of the time we either have to turn away the patient, or we can give them an appointment for the next two or three weeks, which is not the best thing to do, but there is nothing much we can do about it,” Baz said. 


The Pacific Southwest Building in downtown Fresno fades in the distance from high levels of smoke. Air pollution reached dangerous levels in early October from wildfires burning in the Sierra Nevada. Photo by Cresencio Rodriguez-Delgado/PBS NewsHour

Last week, as smoke levels were high, monitors from the San Joaquin Valley Air Pollution Control District recorded pollution made up of microscopic particles — known as PM2.5 — reaching levels that are hazardous to all groups of people. The Environmental Protection Agency considers PM2.5 to be one of the most dangerous forms of pollution because the particles, which are fine particulate matter smaller than 2.5 millionths of a meter, are so tiny they can easily pass through the respiratory tract and reach the lungs and bloodstream. The particles that make up this pollution typically can come from smoke or dust during crop harvests. Monday’s dust storm also elevated the pollution levels for a few hours

Short-term health effects of exposure to PM 2.5 pollution includes eye irritation, sore throat, coughing, sneezing and runny nose, Baz said. Long-term effects include reduced lung function and an increase in deaths from heart disease. Researchers believe the longevity of residents in the San Joaquin Valley is lower because of chronic exposure to pollution.

Questioning health and exercise under pollution

The San Joaquin Valley Air Pollution Control District outlines the risks with each level of air hazard. The agency reports that the amount of PM 2.5 pollution that poses the need for limited time outdoors for people without underlying illnesses is usually below 75 micrograms per cubic meter. Also, sensitive individuals — a category that includes people with asthma, or other heart or lung conditions — are encouraged to exercise entirely indoors under these conditions. 

That wasn’t the case on Oct. 3, when Fresno recorded 104.6 micrograms per cubic meter of PM2.5 pollution — far above the most unhealthy level for all groups of people. That day, about 1,000 runners raced in the California Classic Half Marathon through downtown Fresno.

Kendra Lopez, 33, said she ran the half marathon as training for the Chicago Marathon that took place Oct. 10. Lopez said some of her friends decided at the last minute the air was too unsafe to run, but she decided to race because she had already practiced in early mornings and under the smoky air. 

“I wasn’t out there to run fast,” Lopez said a day after the event, which she finished in an hour and 58 minutes. 

Lopez grew up in Fresno but moved to Los Angeles before moving back to the Valley two years ago, where she has been active in the running community since. Reflecting on the race through the smoke, she said she has always had to make adjustments based on air quality to determine when she could run. 

She used to wonder why more people didn’t run in the city or around her east Fresno neighborhood, but she now believes year-round pollution along with the sharp rise of particulate matter from the wildfires may be a major deterrent.

“I think when it comes to health and wellness, people want to be outdoors. We’ve had a hard year, Lopez said. “How come we always have to be in these situations like, ‘Well, we want to do these things, but we can’t.’ And if we do these things, we’re obviously risking [our health].” 

Dr. Rais Vohra, interim health officer for Fresno County, has considered the region to be “always one disaster away” from a surge in hospitalizations. In COVID-19 briefings, he has addressed the impacts of lingering smoke, saying doctors are worried about the health of the runners or other large groups who may be exposed to the smoke long term.

Baz told the NewsHour that symptoms from PM2.5 exposure are similar to those of COVID-19, and that of a cold or flu, which he said makes it that much more difficult for residents to seek immediate care if they don’t know what is causing their symptoms. He called the situation a “triple whammy.” 

Protecting students from bad air

Preventing exposure to the smoke has become a challenge for officials at schools who now are tasked with making sure students don’t breathe in the toxic smoke. 

Bryan Wells, assistant superintendent for student engagement in the Fresno Unified School District, said the unusual and fast-changing conditions have made staff and teachers extra cautious during a school year when students are having to relearn how to be back in the classroom, and as teachers also try to protect against COVID-19 infections. 

On Oct. 1, the PM2.5 pollution level in Fresno reached 146 parts per billion, way above the most extreme level. 

“It was amazing to see how fast we went from a level three to a level five above in an hour,” Wells said. 

The following week, California Gov. Gavin Newsom visited a Fresno elementary school to sign a $123 billion education bill. Wells said the event was supposed to be held outdoors, but the smoke still had not improved by the middle of the week and the governor spoke indoors. Earlier that day, Wells had gotten an email from a teacher at 6 a.m. local time already concerned about the air quality level. 

Within hours, Wells said, the district moved into a “smoke advisory” day which essentially works similar to a “rainy day schedule” for students. Outside activities were limited and students were kept in classrooms, gymnasiums or cafeterias during their breaks. The district has had to cancel nighttime football games because air pollution reached high levels even during the evening hours. 


Farm fields in California’s San Joaquin Valley are covered in smoke in late September from wildfires burning in the Sierra Nevada. Photo by Cresencio Rodriguez-Delgado/PBS NewsHour

“In my 35 years in education, it’s never been this bad,” Wells said. “Looking at what we need, we need rain, almost of biblical proportions, without flooding out our brothers and sisters that live in the foothills or up in the mountains because of the burn scars [from previous fires].” 

A storm system that moved into the region last Friday brought rain and some snow to the mountains in addition to the high winds that arrived this week and carried dust through the Valley. 

The San Joaquin Valley Air Pollution Control District issued an advisory Monday night for hazardous levels of PM10 pollution. PM10 is made up of slightly larger particles than PM2.5, and usually comes from dust or pollen. 

Dust can also increase the risk of valley fever. According to the Centers for Disease Control and Prevention, breathing microscopic fungal spores from dust can sicken people. The fungal lung infection is most common in the southwestern U.S. 

‘You can’t just hold your breath’

There hasn’t been measurable rainfall in Fresno for many months as the state experiences extreme drought. Last week’s showers on Oct. 8 brought only .40 inches of rain to the Fresno area. The last time the area recorded considerable rain was April 25. 

Pollution was a constant problem in the Valley, even before the wildfires started getting bigger and pushing smoke for longer periods of time, said Catherine Garoupa White, executive director of the Central Valley Air Quality Coalition and professor of geography at California State University, Stanislaus. The only difference is the “seasonality” of the pollution has been fading. 

“What we’re having now, with accelerating climate impacts on an extension of the fire season, is that we’re having particle pollution year round at this point during ozone season,” Garoupa White said. “So it can be really hot, ozone pollution can be getting really high, and now we have [particulate matter] from fires.”  

Ozone pollution is created when ground-level pollutants from sources such as cars, chemical plants or refineries mix with sunlight. While ozone pollution typically forms in hotter months, PM2.5 forms in colder months. 

Local efforts to bring air monitoring to the community level is meant to better inform people about what they’re breathing and when, she added. She said air pollution isn’t distributed equally across the Valley, and if people are able to understand the air quality impacts in their own neighborhood, fewer may end up in the hospital. 

A Stanford University study, released in August, looked at individual behaviors during periods of wildfire smoke and found that direct experiences and access to wildfire smoke information were helpful tools to form perceptions of the threat from smoke pollution. According to the study, “social norms and social support interact in complex, nonlinear ways to influence threat and efficacy perceptions, and directly affect protective health behavior.”

The weeks-long presence of pollution has led local organizations to distribute N95 masks for farmworkers. Air advocates have encouraged others to use air purifiers indoors, since pollution can also enter homes with poorly sealed windows and doors. 

Still, Garoupa White said many face pollution impacts even after visible smoke has cleared. She said the warehouse industry and presence of large heavy trucks in parts of south Fresno pose an air quality danger for communities even after the skies turn blue again.

For this reason, Garoupa White said she worries air pollution can become normalized in communities despite the presence of dense smoke from wildfires growing each year. She said information needs to be distributed on a wider scale for people, not just on how unsafe pollution can be, but ways and resources to protect from it. 

As director of CVAQ, “It’s incredibly depressing to go tell people, ‘Well, the air is unhealthy.’ Because you can’t just stop breathing, right?”

“You can’t just hold your breath until the air gets safe,” Garoupa White added. 

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