The forest fire series in Europe and the world does not stop. The year 2022 is already the most devastating forest fire year for Spain since records began. In Italy alone, almost 33,000 operations were counted nationwide in mid-July, around 4,000 more than in the same period of the previous year. In Portugal, 35 percent more area was destroyed by forest fires last week than in the entire previous year, and the country declared a state of emergency last week. In parts of Germany, too, the risk of forest fires was recently at the highest level. And the fierce fires from the heat and drought continue; currently mainly on the Canary Island of Tenerife, the Greek island of Lesbos and in the Dadia National Park in north-eastern Greece and near the US National Park Yosemite in California.
A forest fire not only harms nature and the climate, but also humans. Exposure to wildfire smoke can cause coughing, wheezing, eye irritation and skin rashes, and other dermatological problems, but it can also have far more far-reaching health consequences.
Because the smoke produced by a forest fire is more toxic than that produced by another type of fire. In addition to plants and trees, cars, buildings and various objects that are in them often burn. The smoke released by the fire thus contains harmful gases, chemicals and particulate matter. It also often contains residues of metals, plastics and other synthetic materials, which pose a serious health risk. This is even more toxic than air pollution. And wildfire smoke can linger in the air for weeks and spread hundreds of miles.
According to the director of the Center for Health and the Environment at the University of California, Davis, Kent Pinkerton, the smoke released by a wildfire causes more inflammation and tissue damage in the human body than the same amount of air pollution.
Studies have found that inhaling wildfire smoke increases the rate of heart attacks, strokes and cardiac arrest. In addition, people who have inhaled the smoke are more likely to develop asthma and other respiratory diseases, as well as a weakened immune system. As a result, patients have to go to the emergency room more often.
Canadian researchers recently found that people who lived outside of urban areas and within 50 kilometers of a forest fire in the past 10 years had a nearly 5 percent higher risk of lung cancer and a 10 percent higher risk of developing a brain tumor than people not exposed to forest fires.
Keith Bein of the University of California, Davis Center for Health and Environment says, “Repeated exposure, summer after summer, is more likely to cause disease.” However, it is difficult to make predictions about the number and duration of forest fires and the components of the smoke.
The increased transmission of Covid-19 is also due to the spread of smoke from wildfires. And women’s pregnancy can be adversely affected: reduced infant weight, premature birth and even pregnancy loss are possible.
In the summer of 2008, forest fires broke out in Davis, California, causing smoke to spread throughout the area. The School of Veterinary Medicine started a long-term study with a few months old rhesus monkeys living in an outdoor enclosure at the California National Primate Research Center. Over the years, researcher Prof. Lisa Miller noticed effects on the immune system and lung functions of the young primates. These are similar to the human lung disease COPD. Those monkeys born the year after the forest fires did not show these symptoms.
A second experiment involving rhesus monkeys in the fall of 2018 showed that animals exposed to smoke from a fire 100 miles away early in pregnancy had an increased risk of miscarriage. For example, 82 percent of pregnancies resulted in successful live births, compared to 86 to 93 percent in the previous nine years.
The researchers made such statements not only in monkeys. After wildfires broke out in the California cities of Sonoma and Napa in 2017, public health science professor and director of the UC Davis Environmental Health Sciences Center Irva Hertz-Picciotto studied women who had smoked cigarettes in 2017 while pregnant or about to become pregnant were exposed to forest fires. Their babies were also examined. Finally, more than half of those surveyed said they had suffered from at least one symptom in the first three weeks after the fires broke out. More than one in five people reported asthma or wheezing. For many, the respiratory problems persisted months after the fires.
“There is still a perception that the effects of poor air quality are temporary, but what we are seeing suggests that the effects continue for many months after the fires — and then fire season begins again,” Hertz-Picciotto said . According to the researcher, symptoms from forest fire smoke can occur more easily with repeated exposure. She agrees with her colleague Keith Bein. “It may take fewer triggers to get symptoms.”
Forest fire smoke can also transport mold from the forest floor over long distances in the air and apparently transmit it to humans. In 2020, Naomi Hauser, an infectious disease specialist and associate clinical professor at UC Davis Health, and her colleagues noticed a rise in mold infections. Patients with burns were particularly affected. Because fire victims but also people with a weakened immune system are more susceptible. The researchers registered a doubling of mold infections and saw a connection to the fire season.
People who work outdoors and children are of increased concern. “Children are very active outdoors, take in more air relative to their lung mass than adults, and are particularly sensitive to wildfire smoke,” said Pinkerton of the University of California, Davis. He explains: “Your immune system is still maturing.” Although there is no detailed knowledge of the long-term effects of inhaling forest fire smoke, the results of corresponding studies are gradually appearing.
Sources: UC Davis Magazine, Reuters, with DPA.