The impact of wildfires in Ukraine on carbon flux and air quality changes by carbon-containing compounds

Author(s):  
Mykhailo Savenets ◽  
Larysa Pysarenko

<p>Wildfires remain among the most challenging problems in Ukraine. Each year numerous cases of open burning contribute to huge carbon emissions and turn into forest fires. Using the Global Fire Emissions Database (GFED4), there were studied an average burned fraction in Ukraine, which equals of about 0.2-0.3. 90% of wildfires appeared on agricultural lands. The total contribution to carbon emissions is 0.2-1.0 g·m<sup>2</sup>·month<sup>-1</sup> with the increasing trend of about 1-2 g·m<sup>2</sup>·month<sup>-1</sup> per decade. There are three periods with the highest carbon emissions: April, July-August and September-October. While a summer maximum is corresponding to unfavorable temperature and moisture regimes, the main reason of wildfires in spring and autumn is the agricultural open burning. Based on the Sentinel-5P data, it was found that wildfires significantly change the seasonality of carbon monoxide (CO) variations. If maximal CO content is mainly observed in winter at the end of the heating season, in Ukraine the highest CO values continue to exist in April until the open burning stops and the resulting forest fires are extinguished. Wildfires caused the CO content increase to 4.0–5.0 mol·m<sup>-2</sup> which is comparable to the most polluted Ukrainian industrial cities. As a result, air quality deterioration observed at the distances more than 200 km from the burned areas. Using the Enviro-HIRLAM simulations, there were estimated black carbon (BC) distribution, which showed elevated content within the lowest 3-km layer. BC content reaches 600 ppbm near the active fires, 150 ppbm at the distance up to 100 km and 30 ppbm at the distance of about 200-500 km.</p>

Introduction. Fires in ecosystems, mostly after open burning, affect Ukrainian territory each year causing flora and fauna damage, soil degradation, pollutants emission, which impact air quality and human health. Fires influence the atmosphere by adding burned products and its further direct and indirect effects. Despite majority of fires are open burning, research of forest fire emissions prevail among Ukrainian scientists. Therefore, the study aimed to analyze the influence of all-type fires in Ukrainian ecosystems on substances fluxes to the atmosphere and possible changes of meteorological processes. Data and methodology. The study uses GFED4 data and inventories for analyses of forest and agricultural burned fraction, carbon and dry matter emissions for the period of 1997–2016. Additional data includes absorbed aerosol index derived from OMI (Aura) instrument and ground-based meteorological measurements. Results. Burning fraction indicates the 10 to 30% of area influencing in case of active fires. More than 90% of fires in Ukrainian ecosystems happened on the agricultural lands. The highest trends of active fires appear on the western and northern part of Ukraine, whereas burned fraction on the central territories reached up to 60% decreasing per decade. Most fires happened during two periods: March – April and July – September. The most severe fires occurred in 1999, 2001, 2005, 2007, 2008 and 2012. Average emissions in Ukraine vary from 0.2 to 1.0 g·m2·month-1 for carbon and from 0.001 to 0.003 kg·m2·month-1 for dry matter. There are three localizations of huge burning products emissions, where maximal average values reach 1.8 g·m2·month-1 for carbon and 0.005 kg·m2·month-1 for dry matter. The biggest one occurred in the Polissia forest region. Despite the maximal emission from forest fires, open burning results the biggest coverage and air quality deteriorating. Absorbing aerosol index (AAI) could be good indicator of fires in Ukrainian ecosystems and burning products emissions. Overall, AAI with values more than 0.2 correspond to dry matter emissions of 0.005–0.01 kg·m2·month-1. If AAI exceed 0.4 usual dry matter emissions exceed 0.02 kg·m2·month-1. The study finds local scale changes of air temperature and days with precipitation due to huge burning products emissions. In case of monthly average AAI exceed 1.2 during fires events, positive air temperature anomaly at the ground decrease from 0.7 to 0.1°C. The main reason is absorption of solar radiation in the atmosphere. During the next month after intensive fires in ecosystems, days with precipitation have twofold decrease: from 13-14 to 7 days with precipitation more than 0 mm, and from 2-3 to 1 day with precipitation more than 5 mm. The reason might be changes of cloudiness formation due to elevated concentrations of carbonaceous aerosols. The results obtained for atmospheric changes is planned to be verified and compared using online integrated atmospheric modelling.


2020 ◽  
Vol 237 ◽  
pp. 03012
Author(s):  
Christoph Senff ◽  
Andrew Langford ◽  
Raul Alvarez ◽  
Tim Bonin ◽  
Alan Brewer ◽  
...  

Recently, two air quality campaigns were conducted in the southwestern United States to study the impact of transported ozone, stratospheric intrusions, and fire emissions on ground-level ozone concentrations. The California Baseline Ozone Transport Study (CABOTS) took place in May – August 2016 covering the central California coast and San Joaquin Valley, and the Fires, Asian, and Stratospheric Transport Las Vegas Ozone Study (FAST-LVOS) was conducted in the greater Las Vegas, Nevada area in May – June 2017. During these studies, nearly 1000 hours of ozone and aerosol profile data were collected with the NOAA TOPAZ lidar. A Doppler wind lidar and a radar wind profiler provided continuous observations of atmospheric turbulence, horizontal winds, and mixed layer height. These measurements allowed us to directly observe the degree to which ozone transport layers aloft were entrained into the boundary layer and to quantify the resulting impact on surface ozone levels. Mixed layer heights in the San Joaquin Valley during CABOTS were generally below 1 km above ground level (AGL), while boundary layer heights in Las Vegas during FAST-LVOS routinely exceeded 3 km AGL and occasionally reached up to 4.5 km AGL. Consequently, boundary layer entrainment was more often observed during FAST-LVOS, while most elevated ozone layers passed untapped over the San Joaquin Valley during CABOTS.


2016 ◽  
Vol 16 (5) ◽  
pp. 3485-3497 ◽  
Author(s):  
Marcella Busilacchio ◽  
Piero Di Carlo ◽  
Eleonora Aruffo ◽  
Fabio Biancofiore ◽  
Cesare Dari Salisburgo ◽  
...  

Abstract. The observations collected during the BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) campaign in summer 2011 over Canada are analysed to study the impact of forest fire emissions on the formation of ozone (O3) and total peroxy nitrates ∑PNs, ∑ROONO2). The suite of measurements on board the BAe-146 aircraft, deployed in this campaign, allows us to calculate the production of O3 and of  ∑PNs, a long-lived NOx reservoir whose concentration is supposed to be impacted by biomass burning emissions. In fire plumes, profiles of carbon monoxide (CO), which is a well-established tracer of pyrogenic emission, show concentration enhancements that are in strong correspondence with a significant increase of concentrations of ∑PNs, whereas minimal increase of the concentrations of O3 and NO2 is observed. The ∑PN and O3 productions have been calculated using the rate constants of the first- and second-order reactions of volatile organic compound (VOC) oxidation. The ∑PN and O3 productions have also been quantified by 0-D model simulation based on the Master Chemical Mechanism. Both methods show that in fire plumes the average production of ∑PNs and O3 are greater than in the background plumes, but the increase of ∑PN production is more pronounced than the O3 production. The average ∑PN production in fire plumes is from 7 to 12 times greater than in the background, whereas the average O3 production in fire plumes is from 2 to 5 times greater than in the background. These results suggest that, at least for boreal forest fires and for the measurements recorded during the BORTAS campaign, fire emissions impact both the oxidized NOy and O3,  but (1 ∑PN production is amplified significantly more than O3 production and (2) in the forest fire plumes the ratio between the O3 production and the ∑PN production is lower than the ratio evaluated in the background air masses, thus confirming that the role played by the ∑PNs produced during biomass burning is significant in the O3 budget. The implication of these observations is that fire emissions in some cases, for example boreal forest fires and in the conditions reported here, may influence more long-lived precursors of O3 than short-lived pollutants, which in turn can be transported and eventually diluted in a wide area.


2004 ◽  
Vol 13 (2) ◽  
pp. 217 ◽  
Author(s):  
A. I. Miranda

Forest fires are an important source of various gases and particles emitted into the atmosphere that may affect the air quality on a local and/or larger scale. Currently, there is a growing awareness that smoke from wildland fires exposes individuals and populations to hazardous air pollutants. In order to understand and to simulate forest fire effects on air quality, several issues should be analysed and integrated: fire progression, fire emissions, atmospheric flow, smoke dispersion and chemical reactions. In spite of the available models to simulate smoke dispersion and the existence of some systems already covering the main questions, there still remains a lack of integration concerning fire progression. Photochemical pollution is also not included in these modelling systems. AIRFIRE is a numerical system, developed to estimate the effects of forest fires on air quality, integrating several components of the problem through the inclusion of different modules, namely the mesoscale meteorological model MEMO, the photochemical model MARS, and the Rothermel fire spread model. The system was applied to simulate plume dispersion from a wildfire that occurred in a coastal area, close to Lisbon city, at the end of September 1991. Results, namely the obtained pollutants concentration fields, point to a significant impact on the local air quality. Obtained wind fields and concentration patterns revealed the presence of sea breezes and also the influence of the fire in the atmospheric flow. Estimated carbon monoxide concentration levels were very high, exceeding the recommended hourly limit value of the World Health Organization, and ozone concentration values pointed to photochemical production.


2018 ◽  
Author(s):  
Marwa Majdi ◽  
Solene Turquety ◽  
Karine Sartelet ◽  
Carole Legorgeu ◽  
Laurent Menut ◽  
...  

Abstract. This study examines the uncertainties on air quality modeling associated with the integration of wildfire emissions in chemistry-transport models (CTMs). To do so, aerosol concentrations during the summer 2007, which was marked by severe fire episodes in the Euro-Mediterranean region especially in Balkan (20–31 July 2007, 24–30 August 2007) and Greece (24–30 August 2007), are analysed. Through comparisons to observations from surface networks and satellite remote sensing, we evaluate the abilities of two CTMs, Polyphemus/Polair3D and CHIMERE, to simulate the impact of fires on the regional particulate matter (PM) concentrations and optical properties. During the two main fire events, fire emissions may contribute up to 90 % of surface PM2.5 concentrations, with a significant regional impact associated with long-range transport. Good general performances of the models and a clear improvement of PM2.5 and aerosol optical depth (AOD) are shown when fires are taken into account in the models with high correlation coefficients. Two sources of uncertainties are specifically analysed in terms of surface PM concentrations and AOD using sensitivity simulations: secondary organic aerosol (SOA) formation from intermediate and semi-volatile organic compounds (I/S-VOCs) and emissions' injection heights. The analysis highlights that surface PM2.5 concentrations are highly sensitive to injection heights (with a sensitivity that can be as high as 50 % compared to the sensitivity for I/S-VOCs emissions which is lower than 30 %). However, AOD which is vertically integrated is less sensitive to the injection heights (mostly below 20 %), but highly sensitive to I/S-VOCs emissions (with sensitivity that can be as high as 40 %). The maximum dispersion, which quantifies uncertainties related to fire emissions modeling, is up to 75 % for PM2.5 in Balkan and Greece, and varies between 36 and 45 % for AOD above fire regions. The simulated number of daily exceedance of World Health Organization (WHO) recommendations for PM2.5 over the considered region reaches 30 days in regions affected by fires and ∼ 10 days in fire plumes which is slightly underestimated compared to available observations. The maximum dispersion (σ) on this indicator is also large (with σ reaching 15 days), showing the need for better understanding of the transport and evolution of fire plumes in addition to fire emissions.


2013 ◽  
Vol 13 (2) ◽  
pp. 4491-4533 ◽  
Author(s):  
M. D. Gibson ◽  
J. R. Pierce ◽  
D. Waugh ◽  
J. S. Kuchta ◽  
L. Chisholm ◽  
...  

Abstract. The source attribution of observed variability of total PM2.5 concentrations over Halifax, Nova Scotia was investigated between 11 July–26 August 2011 using measurements of PM2.5 mass and PM2.5 chemical composition (black carbon, organic matter, anions, cations and 33 elements). This was part of the BORTAS-B (quantifying the impact of BOReal forest fires on Tropospheric oxidants using aircraft and satellites) experiment, which investigated the atmospheric chemistry and transport of seasonal boreal wild fire emissions over eastern Canada in 2011. The US EPA Positive Matrix Factorization (PMF) receptor model was used to determine the average mass (percentage) source contribution over the 45 days, which was estimated to be: Long-Range Transport (LRT) Pollution 1.75 μg m−3 (47%), LRT Pollution Marine Mixture 1.0 μg m−3 (27.9%), Vehicles 0.49 μg m−3 (13.2%), Fugitive Dust 0.23 μg m−3 (6.3%), Ship Emissions 0.13 μg m−3 (3.4%) and Refinery 0.081 μg m−3 (2.2%). The PMF model describes 87% of the observed variability in total PM2.5 mass (bias = 0.17 and RSME = 1.5 μg m−3). The factor identifications are based on chemical markers, and they are supported by air mass back trajectory analysis and local wind direction. Biomass burning plumes, found by other surface and aircraft measurements, were not significant enough to be identified in this analysis. This paper presents the results of the PMF receptor modelling, providing valuable insight into the local and upwind sources impacting surface PM2.5 in Halifax during the BORTAS-B mission.


2016 ◽  
Vol 9 (12) ◽  
pp. 4461-4474 ◽  
Author(s):  
Wei Min Hao ◽  
Alexander Petkov ◽  
Bryce L. Nordgren ◽  
Rachel E. Corley ◽  
Robin P. Silverstein ◽  
...  

Abstract. Black carbon (BC) emitted from fires in northern Eurasia is transported and deposited on ice and snow in the Arctic and can accelerate its melting during certain times of the year. Thus, we developed a high spatial resolution (500 m  ×  500 m) dataset to examine daily BC emissions from fires in this region for 2002–2015. Black carbon emissions were estimated based on MODIS (Moderate Resolution Imaging Spectroradiometer) land cover maps and detected burned areas, the Forest Inventory Survey of the Russian Federation, the International Panel on Climate Change (IPCC) Tier-1 Global Biomass Carbon Map for the year 2000, and vegetation specific BC emission factors. Annual BC emissions from northern Eurasian fires varied greatly, ranging from 0.39 Tg in 2010 to 1.82 Tg in 2015, with an average of 0.71 ± 0.37 Tg from 2002 to 2015. During the 14-year period, BC emissions from forest fires accounted for about two-thirds of the emissions, followed by grassland fires (18 %). Russia dominated the BC emissions from forest fires (92 %) and central and western Asia was the major region for BC emissions from grassland fires (54 %). Overall, Russia contributed 80 % of the total BC emissions from fires in northern Eurasia. Black carbon emissions were the highest in the years 2003, 2008, and 2012. Approximately 58 % of the BC emissions from fires occurred in spring, 31 % in summer, and 10 % in fall. The high emissions in spring also coincide with the most intense period of ice and snow melting in the Arctic.


2001 ◽  
Vol 31 (3) ◽  
pp. 512-525 ◽  
Author(s):  
B D Amiro ◽  
J B Todd ◽  
B M Wotton ◽  
K A Logan ◽  
M D Flannigan ◽  
...  

Direct emissions of carbon from Canadian forest fires were estimated for all Canada and for each ecozone for the period 1959–1999. The estimates were based on a data base of large fires for the country and calculations of fuel consumption for each fire using the Canadian Forest Fire Behaviour Prediction System. This technique used the fire locations and start dates to estimate prevailing fire weather and fuel type for each of about 11 000 fires. An average of 2 × 106 ha·year–1 was burned in this period, varying from 0.3 × 106 ha in 1978 to 7.5 × 106 ha in 1989. Ecozones of the boreal and taiga areas experienced the greatest area burned, releasing most of the carbon (C). The mean area-weighted fuel consumption for all fires was 2.6 kg dry fuel·m–2 (1.3 kg C·m–2), but ecozones vary from 1.8 to 3.9 kg dry fuel·m–2. The mean annual estimate of direct carbon emissions was 27 ± 6 Tg C·year–1. Individual years ranged from 3 to 115 Tg C·year–1. These direct fire emissions represent about 18% of the current carbon dioxide emissions from the Canadian energy sector, on average, but vary from 2 to 75% among years. Post-fire effects cause an additional loss of carbon and changes to the forest sink condition.


2012 ◽  
Vol 12 (18) ◽  
pp. 8727-8750 ◽  
Author(s):  
Ø. Hodnebrog ◽  
S. Solberg ◽  
F. Stordal ◽  
T. M. Svendby ◽  
D. Simpson ◽  
...  

Abstract. The hot summer of 2007 in southeast Europe has been studied using two regional atmospheric chemistry models; WRF-Chem and EMEP MSC-W. The region was struck by three heat waves and a number of forest fire episodes, greatly affecting air pollution levels. We have focused on ozone and its precursors using state-of-the-art inventories for anthropogenic, biogenic and forest fire emissions. The models have been evaluated against measurement data, and processes leading to ozone formation have been quantified. Heat wave episodes are projected to occur more frequently in a future climate, and therefore this study also makes a contribution to climate change impact research. The plume from the Greek forest fires in August 2007 is clearly seen in satellite observations of CO and NO2 columns, showing extreme levels of CO in and downwind of the fires. Model simulations reflect the location and influence of the fires relatively well, but the modelled magnitude of CO in the plume core is too low. Most likely, this is caused by underestimation of CO in the emission inventories, suggesting that the CO/NOx ratios of fire emissions should be re-assessed. Moreover, higher maximum values are seen in WRF-Chem than in EMEP MSC-W, presumably due to differences in plume rise altitudes as the first model emits a larger fraction of the fire emissions in the lowermost model layer. The model results are also in fairly good agreement with surface ozone measurements. Biogenic VOC emissions reacting with anthropogenic NOx emissions are calculated to contribute significantly to the levels of ozone in the region, but the magnitude and geographical distribution depend strongly on the model and biogenic emission module used. During the July and August heat waves, ozone levels increased substantially due to a combination of forest fire emissions and the effect of high temperatures. We found that the largest temperature impact on ozone was through the temperature dependence of the biogenic emissions, closely followed by the effect of reduced dry deposition caused by closing of the plants' stomata at very high temperatures. The impact of high temperatures on the ozone chemistry was much lower. The results suggest that forest fire emissions, and the temperature effect on biogenic emissions and dry deposition, will potentially lead to substantial ozone increases in a warmer climate.


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