Huge plumes of smoke released into the atmosphere by uncontrolled wildfires may be affecting the health of people living hundreds of miles away.
Every year thousands of fires engulf forests, grasslands and moors across Europe. In 2018, more than 204,861 hectares of land were burned in Europe and other Mediterranean countries , while the previous year forest fires destroyed more than 1.2 million hectares. The flames in the Arctic in June set a new record for carbon emissions in 18 years of surveillance.
As trees, shrubs, grass, and peat are engulfed by these fires, huge amounts of smoke, soot, and other pollutants are released into the air . With large fires, smoke can rise many kilometers into the stratosphere and spread over entire regions, causing air pollution in areas far removed from where the flames were.
“In the eastern Mediterranean we get the smoke that comes from the forest fires in Russia and when this happens there is hazy smoke everywhere,” said Professor Athanasios Nenes, an atmospheric chemist at the Institute of Chemical Engineering Sciences in Patras, Greece. “It can be quite dramatic. It is affecting the air quality in entire regions or parts of the continents. “
Professor Nenes is the principal investigator of the PyroTRACH project, which tries to find out how emissions from forest fires (along with other types of biomass burning, such as domestic forest fires) change in the atmosphere and the impact this has on health. human and climate.
Globally, it is estimated that the smoke from wildfires causes more than 339,000 premature deaths a year , far more than those who lose their lives directly in these flames.
The team is regularly taking air samples at three locations in Greece: Crete, Athens and Patras. These are being combined with samples provided by collaborators around the world, including the US, the Arctic, India, Europe, Vietnam, and in the air over the South Atlantic Ocean.
“When you look at these samples, you can find a lot of particles in the air, but you can’t say for sure if they came from burning biomass,” Nenes said. “The idea behind PyroTRACH is to see if we can identify specific fire signatures and, in addition, to track what happens to smoke as it ages in the atmosphere ”.
Weather
To do this, the researchers use a special environmental chamber in the laboratory, which reproduces the conditions found in the atmosphere . They then generate fresh smoke samples by burning different types of plant material, which are then allowed to “age” in the chamber.
Over time, they are able to see how the chemistry of smoke particles changes when exposed to the atmosphere and daily patterns of sunlight and darkness. Portable cameras also allow them to age the smoke produced directly by real fires in the outdoor environment.
“We are trying to understand the lifetime of smoke in the atmosphere and how it evolves chemically,” said Professor Nenes. a greater warming effect on the climate than is currently thought? Or does it supply more nutrients to ecosystems when it falls back to the ground? “
One of the team’s main findings since the five-year project began in 2017 is that the particles released by burning vegetation in wildfires become more toxic over time.
Wildfire smoke can linger in the atmosphere for a couple of weeks as it spreads. In air, smoke particles react chemically with trace radicals (molecules with unpaired electrons) to undergo a process known as oxidation. This converts the compounds in the smoke particles into highly reactive compounds. When breathed in, these reactive compounds (known as free radicals) can damage cells and tissues in the body.
“We know that inhaling smoke when you are near a fire is not good, but we have seen that over time it worsens, it is up to four times more toxic ,” Nenes said, referring to some of the results of his experiment. These results showed that smoke samples taken from the air more than five hours after being released from a fire were twice as toxic as when they were first released, and as they aged in the laboratory, the toxicity increased up to four times the original levels.
“This means that even being away from a fire, if the smoke is directed towards you, it can have a significant impact on your health,” he said. “People may not be aware that they are breathing in the fumes of a distant forest fire, but this will affect your health.
Health
While the exact health effects of inhaling this smoke are not yet fully known, Professor Nenes and his team will pass on their results to another project called REMEDIA. This project focuses on how air pollution affects the lungs , as part of the Human Exposome Network, which focuses on what environmental exposures do to human health.
The reactive compounds in wildfire smoke are believed to have a number of short-term and long-term health effects. They can make people more prone to infections , they can cause breathing difficulties and make some more vulnerable to heart attacks , “Nenes said. At the same time, smoke particles also contain carcinogens (polyaromatic hydrocarbons) that also they rust and become more dangerous, increasing the risk of cancer. “
This increased toxicity is of particular concern as smoke from large wildfires is known to travel across entire continents and even oceans . For example, smoke from the Alberta (Canada) wildfires has been traced to spread along the east coast of the United States across the Atlantic and into Europe in 2019. Similarly, smoke from recent Devastating wildfires in Australia engulfed South America and contamination from Siberian wildfires has spread to western Canada and the United States.
“Smoke from wildfires can circulate around the world,” said Dr. Mike Flannigan, director of the Canadian Association for Wildfire Science at the University of Alberta. “Smoke from intense fires can be injected into the upper atmosphere where strong winds (typically westerly winds) can carry it rapidly around the world.
This means that large wildfires can have a dramatic impact on air quality and visibility in cities far from the source of smoke, which can worsen urban air pollution, increasing the risk of health problems and deaths among residents. inhabitants of those cities.
Smoke
In Europe there are an average of 65,000 forest fires each year , but the region is also engulfed by seasonal clouds of smoke from flames elsewhere.
During the colder winter months, domestic wood burning contributes to a significant fraction of the smoke in the atmosphere, especially in urban areas, according to Professor Nenes.
More work is needed to understand the many sources of air pollution . Unraveling these sources is the goal of the Aeromet project. It is developing new ways to better analyze aerosols and particles that pollute the air, particularly in urban areas in Europe. Currently it is difficult to distinguish between those that come from natural sources, such as the dust in the air and the salt that the wind extracts from the oceans, and those that come from fires, vehicles, industry and other human activities.
Improving the accuracy of the way they are measured and identified could not only help authorities better monitor air pollution, but could also “help identify crucial sources of particulate matter and propose appropriate countermeasures to improve air quality” on the basis for the conclusions, says Dr. Burkhard Beckhoff, coordinator of the Aeromet project and researcher at the Physikalisch-Technische Bundesanstalt of Germany in Berlin.
Prof Nenes hopes that scoring pollution from forest fires and wood burning in homes will help improve climate change models, as some of the soot released by fires, known as brown carbon , plays a role. considerable in absorbing heat from the sun, and increases global warming.
“The smaller brown carbon molecules tend to bleach fairly quickly, but the larger ones are more resistant, creating a low but persistent heating effect, ” he said.
Knowing how much of this brown carbon is produced in wildfires and domestic wood burning would allow climate scientists to make better climate predictions.
With climate models already predicting that wildfires are likely to become more common and intense as global temperatures rise and domestic wood burning increases, the smoke they produce could pose an even greater risk to human health. and the environment, says Nenes.
“I grew up being able to see the effect that fires had on our air, here in Greece,” Nenes said. “It is alarming to think about what we are doing to ourselves and the environment. But we hope that as we understand more this, we can contribute to the policies that must be developed to help mitigate the impact of these fires. “
Artículo original
This article was originally published in Horizon, the EU Research and Innovation Magazine
