As wildfires scorched swaths of land in the wine country of Sonoma County in 2020, sending ash flying and choking the air with smoke, Maria Salinas harvested grapes.Video above: Therapists help people deal with climate anxietyHer saliva turned black from inhaling the toxins, until one day she had so much trouble breathing she was rushed to the emergency room. When she felt better, she went right back to work as the fires raged on."What forces us to work is necessity," Salinas said. "We always expose ourselves to danger out of necessity, whether by fire or disaster, when the weather changes, when it's hot or cold."As climate change increases the frequency and intensity of wildfires around the world, a new study shows that farmworkers are paying a heavy price by being exposed to high levels of air pollution. And in Sonoma County, the focus of the work, researchers found that a program aimed at determining when it was safe to work during wildfires did not adequately protect farmworkers.They recommended a series of steps to safeguard the workers' health, including air quality monitors at work sites, stricter requirements for employers, emergency plans and trainings in various languages, post-exposure health screenings and hazard pay.Farmworkers are "experiencing first and hardest what the rest of us are just starting to understand," Max Bell Alper, executive director of the labor coalition North Bay Jobs with Justice, said Wednesday during a webinar devoted to the research, published in July in the journal GeoHealth. "And I think in many ways that's analogous to what's happening all over the country. What we are experiencing in California is now happening everywhere."Farmworkers face immense pressure to work in dangerous conditions. Many are poor and don't get paid unless they work. Others who are in the country illegally are more vulnerable because of limited English proficiency, lack of benefits, discrimination and exploitation. These realities make it harder for them to advocate for better working conditions and basic rights.Researchers examined data from the 2020 Glass and LNU Lightning Complex fires in northern California's Sonoma County, a region famous for its wine. During those blazes, many farmworkers kept working, often in evacuation zones deemed unsafe for the general population. Because smoke and ash can contaminate grapes, growers were under increasing pressure to get workers into fields.The researchers looked at air quality data from a single AirNow monitor, operated by the Environmental Protection Agency and used to alert the public to unsafe levels, and 359 monitors from PurpleAir, which offers sensors that people can install in their homes or businesses.From July 31 to Nov. 6, 2020, the AirNow sensor recorded 21 days of air pollution the EPA considers unhealthy for sensitive groups and 13 days of poor air quality unhealthy for everyone. The PurpleAir monitors found 27 days of air the EPA deems unhealthy for sensitive groups and 16 days of air toxic to everyone.And on several occasions, the smoke was worse at night. That's an important detail because some employers asked farmworkers to work at night due in part to cooler temperatures and less concentrated smoke, said Michael Méndez, one of the researchers and an assistant professor at University of California-Irvine."Hundreds of farmworkers were exposed to the toxic air quality of wildfire smoke, and that could have detrimental impact to their health," he said. "There wasn't any post-exposure monitoring of these farmworkers."The researchers also examined the county's Agricultural Pass program, which allows farmworkers and others in agriculture into mandatory evacuation areas to conduct essential activities like water or harvest crops. They found that the approval process lacked clear standards or established protocols, and that requirements of the application were little enforced. In some cases, for example, applications did not include the number of workers in worksites and didn't have detailed worksite locations.Irva Hertz-Picciotto, a professor of public health sciences at the University of California-Davis who was not part of the study, said symptoms of inhaling wildfire smoke — eye irritation, coughing, sneezing and difficulty breathing — can start within just a few minutes of exposure to smoke with fine particulate matter.Exposure to those tiny particles, which can go deep into the lungs and bloodstream, has been shown to increase the risk of numerous health conditions such as heart and lung disease, asthma and low birth weight. Its effects are compounded when extreme heat is also present. Another recent study found that inhaling tiny particulates from wildfire smoke can increase the risk of dementia.Anayeli Guzmán, who like Salinas worked to harvest grapes during the Sonoma County fires, remembers feeling fatigue and burning in her eyes and throat from the smoke and ash. But she never went to the doctor for a post-exposure health check up."We don't have that option," Guzmán, who has no health coverage, said in an interview. "If I go get a checkup, I'd lose a day of work or would be left to pay a medical bill."In the webinar, Guzman said it was "sad that vineyard owners are only worried about the grapes" that may be tainted by smoke, and not about how smoke affects workers.A farmworker health survey report released in 2021 by the University of California-Merced and the National Agricultural Workers Survey found that fewer than 1 in 5 farmworkers have employer-based health coverage.Hertz-Picciotto said farmworkers are essential workers because the nation's food supply depends on them."From a moral point of view and a health point of view, it's really reprehensible that the situation has gotten bad and things have not been put in place to protect farmworkers, and this paper should be really important in trying to bring that to light with real recommendations," she said.