Introduction. Forest and landscape fires are among the most terrible and dangerous natural disasters that are widespread in the modern world and in the Russian Federation. Every year, people and animals die from uncontrolled fire, forests are destroyed, the oxygen and heat balance of the Earth is disrupted, the atmosphere, soil, water resources are polluted, there is toxic poisoning by combustion products and destabilization of the habitual lifestyle of the population, as well as air, river communications, rail and automobile traffic [1, 2]. Forest fires cause significant disturbances in aerodynamics and the state of the environment. The resulting convective flows spread gaseous combustion products and aerosols over considerable distances and cause significant harm to human health, the environment, and affect weather conditions [3, 4].

The constantly increasing number of fires and their size determine the relevance of the study  of hazardous factors — the direct and indirect effects of the consequences of forest fires on ecosystems and human health [5, 6]. The forecast assessment of the impact of bulk emissions of combustion products of forest fires is currently not sufficiently developed. It is required to apply a systematic approach that allows taking into account the hazardous factors of fires, including the likelihood of risks to human health. Of undoubted scientific interest is the development of an integrated approach to assessing damage from forest fires, including a comparison of environmental losses at the level of specially protected areas.

The work objective is to perform a comparative analysis of environmental risks for the population of three subjects of the Russian Federation from the Baikal region, and to rank the territories by the level of atmospheric air pollution during forest fire.

Materials and Methods. The initial data were statistical information on forest fires in the Irkutsk region, the Republic of Buryatia and the Trans-Baikal Territory in the period from 2013 to 2020, procedural documents of forest fires, including schemes and types of fires, areas and coordinates of fires, protocols of inspection of the fire site, acts of official investigation and other materials.

Results. The paper analyzes forest fires in the specially protected Baikal natural territory of the Baikal region, their environmental consequences. The emphasis is placed on the establishment of the average annual characteristics of forest fires (number, area, economic damage, specific emissions of combustion products into the atmosphere, risks to public health) in the Baikal natural area, which has a special status.

As you know, the Baikal region covers the territory of the Baikal watershed and includes three subjects of the Russian Federation (Irkutsk Region, Trans-Baikal Territory and the Republic of Buryatia), as well as Mongolia. In accordance with Federal Law No. 94-FZ "On the Protection of Lake Baikal" of May 1, 1999, we distinguish the Baikal Natural Territory — the territory that includes Lake Baikal, the water protection zone adjacent to Lake Baikal, its catchment area within the territory of the Russian Federation, specially protected natural territories adjacent to Lake Baikal, as well as the territory adjacent to Lake Baikal with a width of up to 200 kilometers to the west and northwest of it. This territory is divided into three ecological zones — the central, buffer and ecological zones of atmospheric influence, for each of which the nature management regime is defined (Fig. 1).

Fig. 1. Map of the Baikal natural territory[1]

The Baikal natural area, as well as the Baikal region as a whole, is characterized by high forest cover. For example, the territory of the Irkutsk region has the highest forest cover (78 %) among the subjects of the Russian Federation. There are 21.6 hectares of forested area per capita in the Irkutsk region, which is almost 5 times more than the average in the Russian Federation and 84 times more than in Western Europe. 11.1 % of the all-Russian reserve of mature wood is concentrated on the territory of the region, and the share of the region for coniferous species is 13.4 %. The total area of land occupied by forests in the Republic of Buryatia, as of 01.01.2018, was 29,805.9 thousand hectares or 84.8 % of the total area of the republic. Almost the entire territory of Buryatia is covered with forests, most of which consists of coniferous trees (89.4 % of the total stock of forest plantations). The Trans-Baikal Territory ranks eighth in Russia in terms of the size of the felling-area resources available for forest use. Total forest reserves are estimated at 2.71 billion m3 [7]. As of January 1, 2018, the total forest area of the Trans-Baikal Territory amounted to 34,065.8 thousand hectares. The probability of forest fires in the region is high.

The study is based on the analysis of statistical data of the Ministry of Forestry of the Irkutsk region, the Republican Forestry Agency of the Republic of Buryatia, the Chita Forest Protection Aviation Base, the Ministry of Emergency Situations for the period from 2013 to 2020 [8-10]. The authors carried out calculations using their own or involved methods [8-10]. At the first stage, the mass of substances released from forest fires was measured. The masses of substances were determined according to the method of the authors of the article, taking into account: the area of forest fires (ha), the combustion completeness coefficient, the emission coefficient, the stock of combustible material (kg/m2). The assessment of possible adverse effects on public health — environmental risks — was assessed by hazard coefficients (HQ) and indices (HI) in accordance with the "Guidelines for assessing the risk to public health when exposed to chemicals that pollute the environment" [11].

It is established that annually on the territory of the Baikal region for the period from 2013 to 2020, an average of 3158 forest, 472 steppe and 30 peat fires occurred, as a result of which about 1,128.2 thousand hectares of natural territory were destroyed. Table 1 shows the authors' calculations based on the average values of the numbers of forest fires and their areas in the Baikal region based on information from sources [8–10].

Table 1

Average annual number and area of forest fires, taking into account their types in the Baikal region (2013–2020)

During the studied period, there were mainly ground fires (98 % of the total number) in the Baikal natural territory, as a result of which 80.6 % of forest territories were destroyed.

Based on the information on the species composition of forests in the studied territories, the mass of burned forest-forming species was estimated. It was established that 972.7 thousand tons of pine, 825.1 thousand tons of larch and 664.0 thousand tons of cedar were destroyed per year (based on the information from sources [8–10]) (Table 2).

Table 2

Number of burnt forest-forming species in the Baikal region (average for 2013–2020)

Table 3

Average annual economic damage from the loss of wood destroyed in the Baikal region during forest fires (authors' calculations according to [8–10])

It is established that the annual economic damage from the destruction of forest-forming species, calculated as the product of wood destroyed in a fire by the cost of 1 solid m3, is: in the Irkutsk region — 36.46 million rubles, in the Republic of Buryatia — 31.85 million rubles, in the Trans-Baikal Territory — 13.91 million rubles. The total economic damage in the Baikal region is about 82.22 million rubles (Table 3).

The mass of the i-th type of toxicant released into the atmosphere during wildfires was determined by formula:

where Gi — mass of the i-th type of toxic substance released into the atmosphere; – emission coefficient of the i-th toxicant during the combustion of forest fuel, т/т;  mLGM— mass of burnt forest fuel, t;  — emission coefficient of the i-th toxicant during the combustion of wood, t/t;  — mass of burnt wood (stand, crown), t;  — emission coefficient of the i-th toxicant during the combustion of peat, peat soils, t/t;  — mTmass of burnt peat, peat soils, t.

The calculations have established that the average mass of eco-toxicants entering the atmosphere during fires in the Baikal region reaches 1,465 thousand tons, of which extremely dangerous substances — 0.2 thousand tons, highly dangerous — 4.34 thousand tons, moderately dangerous — 425.1 thousand tons, low-hazard — 517.28 thousand tons, other pollutants — 517.57 thousand tons (Table 4).

Table 4

Annual emission of combustion products by hazard classes as a result of wildfires and fires in 2013–2018 on the territory of the Baikal region

The mass of uncontrolled emissions of toxic substances from forest fires depends on the season of the year (Table 5). The maximum emission of toxicants is observed in the spring (43.6%) and summer (48.4%) periods, in the autumn the emission of toxicants is insignificant (8%).

Table 5

Average annual mass of emissions of toxic combustion products into the atmosphere of the Baikal region, taking into account the time of year

The analysis of the population's treatment in hospitals in the region during the study period showed reliable signs of deterioration in the health of people in the smoke-filled zone. This fact is confirmed by the quantitative growth of the following indicators:

The calculations have established that the average area of smoke in the Baikal region was 6.7 % (Table 6), and the specific load of the atmosphere with toxic combustion products in the Baikal region is 2.95 t/km2∙year-1 (Table 7). The average annual mass of emissions from wildfires is 37.84 % of the average annual mass of emissions from stationary sources of pollution.

Table 6

Average annual area of smoke on the territory of the Baikal region  as a result of wildfires in 2013–2020

Table 7

Average annual specific load on the atmosphere by toxic combustion products in the Baikal region (2013–2018)

The work assessed violations of living conditions and health risk (RN забол) , according to formula:

where  Sзаг. — the area of territory contamination, km2; 0.9 — coefficient that takes into account the proximity of the fire to the populated area;  — population density in the region, people/km2.

The number of potential victims who could get sick from poisoning as a result of wildfires, based on the authors' calculations, is presented in Table 8.

Table 8

Assessment of violations of living conditions and the risk to human health in the Baikal region (average for 2013–2018)

Discussion and Conclusion. The methodology proposed by the authors for ranking territories by environmental risks can be used for predictive assessment of the consequences of fires for public health. The results of the forecast serve to take organizational and administrative measures, including decisions on the involvement of additional forces and equipment, on the evacuation of the population. According to the results of the forecast of the consequences of fires for the health of the population, a fire extinguishing plan is being developed, which determines the methods and tactics of fire elimination, the distribution of forces and means, the decisive direction of hostilities, etc. According to the greatest contribution to the deterioration of living conditions and the risk of poisoning by combustion products, the studied territories are ranked in the following order: Irkutsk region – Republic of Buryatia – Trans-Baikal Territory.

Thus, the authors have carried out a comparative analysis of the levels of atmospheric air pollution from forest fires in the Baikal region and found that:

Received 15.08.2022.

Revised 13.09.2022.

Accepted 13.09.2022.

About the Authors:

Timofeeva, Svetlana S., Head, Department of Industrial Ecology and Life Safety, Irkutsk National Research Technical University (83, Lermontov str., Irkutsk, 664074, RF), Dr. Sci. (Eng.), Professor, ScopusID, ORCID, sstimofeeva@mail.ru

Garmyshev, Vladimir V., Associate professor, Department of Industrial Ecology and Life Safety, Irkutsk National Research Technical University (83, Lermontov str., Irkutsk, 664074, RF), Cand.Sci. (Eng.), ScopusID, ORCID, diamant1959@mail.ru

Astrakhantseva, Aleksandra Yu., Postgraduate student, Department of Industrial Ecology and Life Safety, Irkutsk National Research Technical University (83, Lermontov str., Irkutsk, 664074, RF), ORCID, aleksandraastra@yandex.ru

Claimed contributorship:

Conflict of interest statement

The authors do not have any conflict of interest.

All authors have read and approved the final manuscript.

[1] Baikal Natural Territory.  Protected Baikal Region. Available from: https://baikal-1.ru/tourism/baikal-natural-territory (accessed  02.08.2022). (In Russ.).