(ORDO NEWS) — This is five to six times more than previously thought. Moreover, the vast majority of people do not die from the flame itself.
In the United States, the statistics of deaths from natural fires have been kept for a long time. During the counting period, the number of casualties dropped noticeably.
For example, in 1978 there were officially (we will show why this word is important) 7395 people. In 2003 – 3925 people, and in 2018 – only 3655.
As a rule, the total area of ​​natural fires in the United States per year does not exceed 25 thousand square kilometers, although a hundred years ago it exceeded 100 thousand square kilometers.
At the same time, formally much fewer people die from natural fires, since fires occur mainly in the sparsely populated Asian part of the country.
In the new work of American researchers in Environmental Research Letters , an attempt was made to calculate the victims of wildfires in the United States more fully, taking into account the number of victims from powerful air pollution, an indispensable companion of wildfires.
As is known, when burned, wood produces significantly more microparticles with a diameter of 2.5 micrometers and less than even coal (the record holder for emissions of microparticles for standard fossil fuels).
Microparticles of such small sizes freely enter the blood through the lungs, where they become centers of thrombosis, seriously increasing the frequency of heart attacks and strokes.
The authors of a new study examined the impact of microparticles from wildfires in the United States (excluding Alaska and overseas territories) for 2003-2018.
They found that, depending on the number of fires in a given year, such fires produce from 5 to 10% of microparticles (from 2.5 micrometers or less) that generally enter the air of this country.
These are very high figures, since not much wood pulp burns in forest fires, and more than a billion tons of fossil fuels are burned in the States per year (over three tons per capita).
However, high specific particulate emissions from the combustion of wood and plant biomass have allowed it to make a disproportionately large contribution to total air pollution.
In the zones of active fires, as noted in the work, the concentration of microparticles of 2.5 micrometers or less reached 5000 micrograms per cubic meter of air.
The so-called safe level (many scientists consider it only conditionally safe) concentrations of microparticles in the US is 35 micrograms per cubic meter.
The number of victims from these microparticles for the year with weak fires (2003) was 7.3 thousand people, and for the year with serious fires – 20.0 thousand.
For calculations, the authors of the work used a comparison of mortality in areas close to natural fires with mortality in the same age groups, but in areas more distant from fires.
It turns out that for 2003 the real number of victims from wildfires is three times higher than the official one, and for 2018 it is about half a dozen times higher than the official one.
It should be noted that the authors of the press release on the new study and representatives of the Western scientific community misunderstood the conclusions of the work.
In particular, they claim that 80% of all microparticle victims in the United States died precisely from microparticles brought by wildfires.
In fact, the work says something completely different: 80% of the 20,000 fire victims in 2018 died from those natural fires that were caused by a person.
Another 20% died from microparticles formed in fires from lightning strikes and other natural causes.
The real number of victims of microparticles in the United States is much higher than hundreds of thousands of people a year – most of them are victims of thermal power plants and cars.
The American work is interesting in that it shows a significant underestimation of the harm of natural fires for society.
It turns out that in our country the number of victims of microparticles from such fires can be radically higher than the number of those who died in their flames.
The same conclusion holds true for the world as a whole.
It is worth noting that on the planet as a whole, the area of ​​natural fires is seriously decreasing.
According to satellite images, in the first 18 years of the 21st century, their area in the world has fallen by a quarter. (mainly due to changes in agricultural practices in Africa and some other parts of the third world)
In theory, in the distant future, the situation will change: according to paleobotanical data, with a serious warming, the larches of the northern taiga are replaced by broad-leaved trees (oaks and others), which blocks frequent forest fires.
But in practice, it will take centuries for Siberian broadleaf trees to colonize, and until then, periodic fires will inevitably be a serious problem for the health of local residents.
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