Burning Markers Research Articles

Residential Wood Burning and Vehicle Emissions as Major Sources of Environmentally Persistent Free Radicals in Fairbanks, Alaska.

Environmentally persistent free radicals (EPFRs) play an important role in aerosol effects on air quality and public health, but their atmospheric abundance and sources are poorly understood. We measured EPFRs contained in PM2.5 collected in Fairbanks, Alaska, in winter 2022. We find that EPFR concentrations were enhanced during surface-based inversion and correlate strongly with incomplete combustion markers, including carbon monoxide and elemental carbon (R2 > 0.75). EPFRs exhibit moderately good correlations with PAHs, biomass burning organic aerosols, and potassium (R2 > 0.4). We also observe strong correlations of EPFRs with hydrocarbon-like organic aerosols, Fe and Ti (R2 > 0.6), and single-particle mass spectrometry measurements reveal internal mixing of PAHs, with potassium and iron. These results suggest that residential wood burning and vehicle tailpipes are major sources of EPFRs and nontailpipe emissions, such as brake wear and road dust, may contribute to the stabilization of EPFRs. Exposure to the observed EPFR concentrations (18 ± 12 pmol m-3) would be equivalent to smoking ∼0.4-1 cigarette daily. Very strong correlations (R2 > 0.8) of EPFR with hydroxyl radical formation in surrogate lung fluid indicate that exposure to EPFRs may induce oxidative stress in the human respiratory tract.

Specific biomass burning tracers in air pollution in Zagreb, Croatia

Biomass burning is considered a renewable energy source whose household usage is rapidly increasing throughout Europe, largely encouraged by the rising cost of other energy sources. With all the advantages that characterize such an energy source, there are several disadvantages mostly from the air quality standpoint, and consequently with regard to the influence it may have on human health and climate change. Considering the side effects of air pollution, it is important to identify the composition and sources of air pollutants precisely. This study investigated the presence of biomass combustion-specific tracers in the air of Zagreb, Croatia, a city affected by increased air pollution mostly during wintertime. Biomass burning markers in terms of anhydrosugars, namely levoglucosan, mannosan, and galactosan were monitored in particulate matter PM10. A sampling of PM10 particulate matter was conducted in parallel at measuring stations in the northern and southern part of the city during 30 days in each season in 2020. The results showed a significant seasonal difference in PM10 and anhydrosugar levels at both measuring stations with the same seasonal trend decreasing as follows: winter, autumn, spring, summer. Both PM10 and anhydrosugar concentrations were higher in the southern compared to the northern station. Average winter PM10 levels were 58 μg m−3 at the southern and 51 μg m−3 at the northern station, while average levoglucosan levels were 3.68 and 1.64 μg m−3 at the southern and northern stations, respectively. An average levoglucosan/PM10 contribution of 6.3 % was determined at the southern, and 3.2 % at the northern measuring station. The differences in contribution can be explained by areas more populated by households using biomass for residential heating, the dominant wind direction in the area, and influences from other districts, including long- or close-range transport. Linear regression indicated a weak correlation (R2 = 0.32) of anhydrosugars between the stations.

Sources of personal PM2.5 exposure during pregnancy in the MADRES cohort

BackgroundPersonal exposure to fine particulate matter (PM2.5) is impacted by different sources each with different chemical composition. Determining these sources is important for reducing personal exposure and its health risks especially during pregnancy.ObjectiveIdentify main sources and their contributions to the personal PM2.5 exposure in 213 women in the 3rd trimester of pregnancy in Los Angeles, CA.MethodsWe measured 48-hr integrated personal PM2.5 exposure and analyzed filters for PM2.5 mass, elemental composition, and optical carbon fractions. We used the EPA Positive Matrix Factorization (PMF) model to resolve and quantify the major sources of personal PM2.5 exposure. We then investigated bivariate relationships between sources, time-activity patterns, and environmental exposures in activity spaces and residential neighborhoods to further understand sources.ResultsMean personal PM2.5 mass concentration was 22.3 (SD = 16.6) μg/m3. Twenty-five species and PM2.5 mass were used in PMF with a final R2 of 0.48. We identified six sources (with major species in profiles and % contribution to PM2.5 mass) as follows: secondhand smoking (SHS) (brown carbon, environmental tobacco smoke; 65.3%), fuel oil (nickel, vanadium; 11.7%), crustal (aluminum, calcium, silicon; 11.5%), fresh sea salt (sodium, chlorine; 4.7%), aged sea salt (sodium, magnesium, sulfur; 4.3%), and traffic (black carbon, zinc; 2.6%). SHS was significantly greater in apartments compared to houses. Crustal source was correlated with more occupants in the household. Aged sea salt increased with temperature and outdoor ozone, while fresh sea salt was highest on days with westerly winds from the Pacific Ocean. Traffic was positively correlated with ambient NO2 and traffic-related NOx at residence. Overall, 76.8% of personal PM2.5 mass came from indoor or personal compared to outdoor sources.ImpactWe conducted source apportionment of personal PM2.5 samples in pregnancy in Los Angeles, CA. Among identified sources, secondhand smoking contributed the most to the personal exposure. In addition, traffic, crustal, fuel oil, fresh and aged sea salt sources were also identified as main sources. Traffic sources contained markers of combustion and non-exhaust wear emissions. Crustal source was correlated with more occupants in the household. Aged sea salt source increased with temperature and outdoor ozone and fresh sea salt source was highest on days with westerly winds from the Pacific Ocean.

Mass spectrometric analysis of unprecedented high levels of carbonaceous aerosol particles long-range transported from wildfires in the Siberian Arctic

Abstract. Wildfires in Siberia generate large amounts of aerosols, which may be transported over long distances and pose a threat to the sensitive ecosystem of the Arctic. Particulate matter (PM) of aged wildfire plumes originating from Yakutia in August 2021 was collected in Nadym and on Bely Island (both in northwestern Siberia). An advanced analysis of the chemical composition of aerosol particles was conducted through a multi-wavelength thermal–optical carbon analyzer (TOCA) coupled to resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS) as well as through ultra-high-resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). In Nadym, concentrations of organic carbon (OC) and elemental carbon (EC) peaked at 100 and 40 µg m−3, respectively, associated with Angström absorption exponents for 405 and 808 nm (AAE405/808) between 1.5 and 3.3. The weekly average on Bely Island peaked at 8.9 µg m−3 of OC and 0.3 µg m−3 of EC and AAE405/808 close to unity. In particular, ambient aerosol in Nadym had a distinct biomass burning profile with pyrolysis products from carbohydrates, such as cellulose and hemicellulose, as well as lignin and resinoic acids. However, temporarily higher concentrations of five- and six-ring polycyclic aromatic hydrocarbons (PAHs), different from the PAH signature of biomass burning, suggest a contribution of regional gas flaring. FT-ICR MS with electrospray ionization (ESI) revealed a complex mixture of highly functionalized compounds, containing up to 20 oxygen atoms, as well as nitrogen- and sulfur-containing moieties. Concentrations of biomass burning markers on Bely Island were substantially lower than in Nadym, flanked by the appearance of unique compounds with higher oxygen content, higher molecular weight, and lower aromaticity. Back-trajectory analysis and satellite-derived aerosol optical depth suggested long-range transport of aerosol from the center of a Yakutian wildfire plume to Nadym and from the plume periphery to Bely Island. Owing to lower aerosol concentrations in the plume periphery than in its center, it is demonstrated how dilution affects the chemical plume composition during atmospheric aging.

Particulate matter from a tropical city in southeast Brazil: Impact of biomass burning on polycyclic aromatic compounds levels, health risks, and in vitro toxicity

In the context of a rising global temperature, biomass burning represents an increasing risk to human health, due to emissions of highly toxic substances such as polycyclic aromatic hydrocarbon (PAHs). Size-segregated particulate matter (PM) was collected in a region within the sugarcane belt of São Paulo state (Brazil), where biomass burning is still frequent, despite the phasing out of manual harvesting preceded by fire. The median of the total concentration of the 15 PAHs determined was 2.3 ± 1.8 ng m−3 (n = 19), where 63% of this content was in PM1.0. Concentrations of OPAHs and NPAHs were about an order of magnitude lower. PM2.5 collected in the dry season, when most of the fires occur, presented PAHs and OPAHs total concentrations three times higher than in the wet season, showing positive correlations with fire foci number and levoglucosan (a biomass burning marker). These results, added to the fact that biomass burning explained 65% of the data variance (PCA analysis), evidenced the importance of this practice as a source of PAHs and OPAHs to the regional atmosphere. Conversely, NPAHs appeared to be mainly derived from diesel-powered vehicles. The B[a]P equivalent concentration was estimated to be 4 times higher in the dry season than in the wet season, and was greatly increased during a local fire event. Cytotoxicity and genotoxicity of PM1.0 organic extracts were assessed using in vitro tests with human liver HepG2 cells. For both types of tests, significant toxicity was only observed for samples collected during the dry season. Persistent DNA damage that may have impaired the DNA repair system was also observed. The results indicated that there was a health risk associated with the air particulate mixture, mainly related to biomass burning, demonstrating the urgent need for better remediation actions to prevent the occurrence of burning events.

Gas–particle partitioning of semivolatile organic compounds when wildfire smoke comes to town

Abstract. Wildfires have become an increasingly important source of organic gases and particulate matter in the western USA. A large fraction of organic particulate matter emitted in wildfires is semivolatile, and the oxidation of organic gases in smoke can form lower-volatility products that then condense on smoke particulates. In this research, we measured the gas- and particle-phase concentrations of semivolatile organic compounds (SVOCs) during the 2017 northern California wildfires in a downwind urban area, using semivolatile thermal desorption aerosol gas chromatography (SV-TAG), and measured SVOCs in a rural site affected by biomass burning using cTAG (comprehensive thermal desorption aerosol gas chromatography mass spectrometry) in Idaho in 2018. Commonly used biomass burning markers such as levoglucosan, mannosan, and nitrocatechols were found to stay predominantly in the particle phase, even when the ambient organic aerosol (OA) was relatively low. The phase partitioning of SVOCs is observed to be dependent on their saturation vapor pressure, while the equilibrium absorption model underpredicts the particle-phase fraction of most of the compounds measured. Wildfire organic aerosol enhanced the condensation of polar compounds into the particle phase but not some nonpolar compounds, such as polycyclic aromatic hydrocarbons.

Aged polycyclic aromatic hydrocarbons as stratigraphic marker in the Anthropocene: Evidence from Tibetan Lake sediments

Polycyclic aromatic hydrocarbons (PAHs) were supposed to serve as combustion marker reflecting the past energy use, but it was unclear whether their sediment records in the Anthropocene were “weathered” due to aging-induced formation of bound residues. In this study, the total concentration of PAHs (the sum of rapid desorption, slow desorption, and bound residue fractions) were determined in four dated sediment cores from eastern to central Tibet using multi-step sequential extraction method. The total 16 PAH concentrations were 11.8, 13.5, 18.9, and 29.4 ng/g dw (in average) in the Co Ngoin, Pung Co, Ahung Co, and Putok lakes, respectively. The stratigraphic records and estimated source contributions of PAHs in different areas of Tibet exhibited a coherent change in the mid-20th century in response to the Holocene-Anthropocene transition. The sediment PAHs also displayed a comparable pattern when the bound residue fraction was not accounted for, suggesting their effective retainability under natural aging conditions. This may be elucidated by the enduring forward and back conversions between slow desorption and bound residue fractions, which manifested similar time-dependent variations across PAH congeners. The distinct conversion tendencies of different congeners were predicted by the binding affinity of congeners to surface/inner regions of organic matter using molecular docking simulations. Our findings demonstrate the persistence of sediment PAH records under natural aging and validate the use of PAH documentary evidence for investigating the Anthropocene.

Chemical evolution of primary and secondary biomass burning aerosols during daytime and nighttime

Abstract. Primary emissions from wood and pellet stoves were aged in an atmospheric simulation chamber under daytime and nighttime conditions. The aerosol was analyzed with online aerosol mass spectrometry and offline Fourier transform infrared spectroscopy (FTIR). Measurements using the two techniques agreed reasonably well in terms of the organic aerosol (OA) mass concentration, OA:OC trends, and concentrations of biomass burning markers – lignin-like compounds and anhydrosugars. Based on aerosol mass spectrometry, around 15 % of the primary organic aerosol (POA) mass underwent some form of transformation during daytime oxidation conditions after 6–10 h of atmospheric exposure. A lesser extent of transformation was observed during the nighttime oxidation. The decay of certain semi-volatile (e.g., levoglucosan) and less volatile (e.g., lignin-like) POA components was substantial during aging, highlighting the role of heterogeneous reactions and gas–particle partitioning. Lignin-like compounds were observed to degrade under both daytime and nighttime conditions, whereas anhydrosugars degraded only under daytime conditions. Among the marker mass fragments of primary biomass burning OA (bbPOA), heavy ones (higher m/z) were relatively more stable during aging. The biomass burning secondary OA (bbSOA) became more oxidized with continued aging and resembled that of aged atmospheric organic aerosols. The bbSOA formed during daytime oxidation was dominated by acids. Organonitrates were an important product of nighttime reactions in both humid and dry conditions. Our results underline the importance of changes to both the primary and secondary biomass burning aerosols during their atmospheric aging. Heavier fragments from aerosol mass spectrometry seldom used in atmospheric chemistry can be used as more stable tracers of bbPOA and, in combination with the established levoglucosan marker, can provide an indication of the extent of bbPOA aging.

Residual impacts of a wildland urban interface fire on urban particulate matter and dust: a study from the Marshall Fire

The impacts of wildfires along the wildland urban interface (WUI) on atmospheric particulate concentrations and composition are an understudied source of air pollution exposure. To assess the residual impacts of the 2021 Marshall Fire (Colorado), a wildfire that predominantly burned homes and other human-made materials, on homes within the fire perimeter that escaped the fire, we performed a combination of fine particulate matter (PM2.5) filter sampling and chemical analysis, indoor dust collection and chemical analysis, community scale PurpleAir PM2.5 analysis, and indoor particle number concentration measurements. Following the fire, the chemical speciation of dust collected in smoke-affected homes in the burned zone showed elevated concentrations of the biomass burning marker levoglucosan (medianlevo = 4147 ng g−1), EPA priority toxic polycyclic aromatic hydrocarbons (median Σ16PAH = 1859.3 ng g−1), and metals (median Σ20Metals = 34.6 mg g−1) when compared to samples collected in homes outside of the burn zone 6 months after the fire. As indoor dust particles are often resuspended and can become airborne, the enhanced concentration of hazardous metals and organics within dust samples may pose a threat to human health. Indoor airborne particulate organic carbon (median = 1.91 μg m−3), particulate elemental carbon (median = .02 μg m−3), and quantified semi-volatile organic species in PM2.5 were found in concentrations comparable to ambient air in urban areas across the USA. Particle number and size distribution analysis at a heavily instrumented supersite home located immediately next to the burned area showed indoor particulates in low concentrations (below 10 μg m−3) across various sizes of PM (12 nm–20 μm), but were elevated by resuspension from human activity, including cleaning.Graphical

Brown Coal and Logwood Combustion in a Modern Heating Appliance: The Impact of Combustion Quality and Fuel on Organic Aerosol Composition.

Residential heating with solid fuels is one of the major drivers for poor air quality in Central and Eastern Europe, and coal is still one of the major fuels in countries, such as Poland, the Czech Republic, and Hungary. In this work, emissions from a single-room heater fueled with brown coal briquettes (BCBs) and spruce logs (SLs) were analyzed for signatures of inorganic as well as semivolatile aromatic and low-volatile organic constituents. High variations in organic carbon (OC) emissions of BCB emissions, ranging from 5 to 22 mg MJ-1, were associated to variations in carbon monoxide (CO) emissions, ranging from 900 to 1900 mg MJ-1. Residential BCB combustion turned out to be an equally important source of levoglucosan, an established biomass burning marker, as spruce logwood combustion, but showed distinct higher ratios to manosan and galactosan. Signatures of polycyclic aromatic hydrocarbons emitted by BCB combustion exhibited defunctionalization and desubstitution with increasing combustion quality. Lastly, the concept of island and archipelago structural motifs adapted from petroleomics is used to describe the fraction low-volatile organic compounds in particulate emissions, where a transition from archipelago to island motifs in relation with decreasing CO emissions was observed in BCB emissions, while emissions from SL combustion exhibited the island motif.

Separation Method for Cross-Aliased Near-IR Absorption Lines of C2H4: A Coal Spontaneous Combustion Marker

Separation Method for Cross-Aliased Near-IR Absorption Lines of C2H4: A Coal Spontaneous Combustion Marker

Taiga fire on Bolshoy Ushkany Island as a model case of forest soil transformation and potential source of eutrophication in Lake Baikal coastal zone

Abstract. The soils of a model site in Severnaya Bay, affected by fire in June 2015, on Bolshoy Ushkany Island (Lake Baikal) were studied. About 70% of the Island taiga burned. The bloom of cyanoprokaryotes in the coastal zone and their massive wash-ups were observed in this bay a year later, in summer 2016. When studying the soils at two points of observation (a high and a low-intensity fire), we focused on geochemically congugated soil profiles. Wildfire strongly affected top soil horizons (4 5 cm), entailing changes in charred roots biomass, soot, charcoal and structural aggregate stability. Migration and accumulation of total organic carbon (30 35 mg/g), N-NH4 (40 mg/kg), phosphates (104 mg/kg) detected at the foot of the slope, were 1.5 3 times higher than the content of these elements in the unburned soil. The slope migration of pyrogenic carbon was traced studying polycyclic aromatic hydrocarbons (PAHs). Retene, a marker of wood combustion, comprised 80-90% of PAHs. In the upper part of the slope, PAH was 270 ng/g, in the transit position 47 ng/g. In the lower part, due to the accumulation of pyrogenic organic compounds, the content of PAH increased to 100 ng/g. Post-pyrogenic slope erosion was detected a year after the fire in Severnaya Bay. Biogenic migration and accumulation in the beach area (including interstitial water) can have consequences as a potential factor in the eutrophication of Lake Baikal coastal zone.

Source apportionment of VOCs, IVOCs and SVOCs by positive matrix factorization in suburban Livermore, California

Abstract. Gas- and particle-phase molecular markers provide highly specific information about the sources and atmospheric processes that contribute to air pollution. In urban areas, major sources of pollution are changing as regulation selectively mitigates some pollution sources and climate change impacts the surrounding environment. In this study, a comprehensive thermal desorption aerosol gas chromatograph (cTAG) was used to measure volatile, intermediate-volatility and semivolatile molecular markers every other hour over a 10 d period from 11 to 21 April 2018 in suburban Livermore, California. Source apportionment via positive matrix factorization (PMF) was performed to identify major sources of pollution. The PMF analysis identified 13 components, including emissions from gasoline, consumer products, biomass burning, secondary oxidation, aged regional transport and several factors associated with single compounds or specific events with unique compositions. The gasoline factor had a distinct morning peak in concentration but lacked a corresponding evening peak, suggesting commute-related traffic emissions are dominated by cold starts in residential areas. More monoterpene and monoterpenoid mass was assigned to consumer product emissions than biogenic sources, underscoring the increasing importance of volatile chemical products to urban emissions. Daytime isoprene concentrations were controlled by biogenic sunlight- and temperature-dependent processes, mediated by strong midday mixing, but gasoline was found to be the dominant and likely only source of isoprene at night. Biomass burning markers indicated residential wood burning activity remained an important pollution source even in the springtime. This study demonstrates that specific high-time-resolution molecular marker measurements across a wide range of volatility enable more comprehensive pollution source profiles than a narrower volatility range would allow.

Indurated soil nodules: A vestige of ancient agricultural practices?

AbstractThe identification of controlled fires in ancient agricultural systems is important for understanding how past societies managed the landscape. Although the use of fire in agriculture is documented in recent historical records, and combustion markers can persist in soils over a long time scale, this is a complex issue because combustion traits in general are ubiquitous. Archaeopedological surveys undertaken in an ancient forest in Burgundy (France) have led to the recovery of several red indurated nodules scattered in the soils. Gallo‐Roman housing structures and parcels were recognized using light detection and ranging mapping, stimulating questions about the understanding of the nature of these nodules. Elemental and structural analyses by X‐ray fluorescence and X‐ray diffraction (XRD) confirmed the local origin of these features by comparing their composition with on‐site sediments, and thermoluminescence dating placed the samples in the Medieval period. The results cast light on the nature of the nodules and how they can be related to controlled fires used in agricultural practices. Even though questions remain about which processes lead to the formation of the nodules, the firing temperature estimated via XRD analysis seems to be in agreement with that used in the “paring‐and‐burning” technique. The present study provides new information about medieval agriculture practices from the 10th to the 12th centuries CE and shows how past societies managed the opening and maintenance of agricultural fields using natural resources and “archaeological” remains from the antique period.

Spatially calibrating polycyclic aromatic hydrocarbons (PAHs) as proxies of area burned by vegetation fires: Insights from comparisons of historical data and sedimentary PAH fluxes

Many regions worldwide have experienced increasing wildfire activity in recent years and climate changes are predicted to result in more frequent and severe fires. Reconstruction of past fire activity offers paleoenvironmental context for modern and future burning. Pyrogenic polycyclic aromatic hydrocarbons (PAHs) have been increasingly used as a molecular biomarker for fire occurrence in the paleorecord and offer opportunity for nuanced reconstructions of fire characteristics. A suite of PAHs is produced during combustion, and the emission amount and assemblage is influenced by many variables including fuel type, fire temperature, and oxygen availability. Despite recent advances in understanding the controls and taphonomy of these biomass burning markers, the spatial scale of this proxy is unknown. In this paper, measurements of PAH fluxes preserved in a lake sediment archive from the Sierra Nevada, California were compared with a historical geographic information system (GIS) dataset of area burned up to 150 km distance from the lake to determine the spatial scales for which these biomarkers are reliable proxies of biomass burning. The PAH fluxes in the Swamp Lake sediments record a change in the relative anthropogenic and pyrogenic sourcing of PAHs. Anthropogenic pollution sources could explain why some PAHs (fluoranthene (Fl), pyrene (Py), benz[a]anthracene (BaA), retene (Ret), benzo[a]pyrene (BaP), dibenzo[a,h]anthracene (DA) and ideno[1,2,3-cd]pyrene (IP)) did not correlate with area burned within 150 km. This indicates that individual PAHs may have different efficacies in recording area burned and be more susceptible to masking of fire signals by pollution sources. Despite these complications, we find that the PAHs naphthalene (Na), acenaphthene (Ace), fluorene (F), and anthracene (An) are reliable local proxies of area burned (within 40 km), whereas the PAHs phenanthrene (Phe), chrysene (Ch), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), and benzo[g,h,i]perylene (Bghi) are both reliable local (within 36 km) as well as more regional (as much as 75 km for phenanthrene (Phe), chrysene (Ch), and benzo[g,h,i]perylene (Bghi) or 150 km for benzo[b]fluoranthene (BbF) and benzo[k]fluoranthene (BkF)) area burned proxies. Comparisons of PAH fluxes with charcoal accumulation rates in the same sediments suggest that pyrogenic particulate transport modulates low to mid-molecular weight PAHs via adsorption. Overall, the results show that PAH records integrate a combination of spatial signals of area burned and measurement of individual PAHs may enable cross-scale paleofire reconstructions.

Emission Spectra of Hydrocarbon Flames Doped with Phosphorus-Containing Compounds

Phosphorus-containing compounds, including organophosphorus substances, are valuable laboratory flame additives for understanding the combustion behavior of sarin. Chemiluminescence features of excited intermediate species are useful markers of combustion, but an effective chemiluminescence-based combustion diagnostic for phosphorus-based compounds is yet to be developed. In this study, chemiluminescence spectra of atmospheric-pressure flames doped with three phosphorus-containing compounds, namely, dimethyl methylphosphonate, diisopropyl methylphosphonate, and phosphoric acid (), were obtained in two flame configurations, namely, spherically expanding flames and piloted liquid-spray flames. The spectra are compared with those obtained from undoped flames fueled by methane and methanol, respectively. Spectra were recorded for the wavelength range of 200–800 nm and for three equivalence ratios (, 1.0, 1.2) of spherical flames. For both flame configurations, the intensity of the doped flame emission increased relative to the neat flames by over an order of magnitude, but no clear spectral features besides a broad, featureless continuum emission could be identified. No significant difference was observed between the spectra of the spray flames doped with and with diisopropyl methylphosphonate. The observance of a continuum emission for all the doped flames is attributed to blackbody emission, likely resulting from high-temperature soot particles in the flame originating from condensed, phosphorus-containing combustion products. However, unique, narrow chemiluminescence features specific to phosphorus combustion could not be identified at this time.

Archaeometric evidence for the earliest exploitation of lignite from the bronze age Eastern Mediterranean

This paper presents the earliest evidence for the exploitation of lignite (brown coal) in Europe and sheds new light on the use of combustion fuel sources in the 2nd millennium BCE Eastern Mediterranean. We applied Thermal Desorption/Pyrolysis–Gas Chromatography-Mass Spectrometry and Polarizing Microscopy to the dental calculus of 67 individuals and we identified clear evidence for combustion markers embedded within this calculus. In contrast to the scant evidence for combustion markers within the calculus samples from Egypt, all other individuals show the inhalation of smoke from fires burning wood identified as Pinaceae, in addition to hardwood, such as oak and olive, and/or dung. Importantly, individuals from the Palatial Period at the Mycenaean citadel of Tiryns and the Cretan harbour site of Chania also show the inhalation of fire-smoke from lignite, consistent with the chemical signature of sources in the northwestern Peloponnese and Western Crete respectively. This first evidence for lignite exploitation was likely connected to and at the same time enabled Late Bronze Age Aegean metal and pottery production, significantly by both male and female individuals.

Evidence of Smoke From Wildland Fire in Surface Water of an Unburned Watershed

AbstractLarge wildland fires generate smoke that can compromise air quality over a wide area. Limited studies have suggested that smoke constituents may enter natural water bodies. In an 18‐year water monitoring study, we examined whether smoke from distant wildland fires had a detectable effect on ion content in a mountain river in an unburned watershed. Significant local smoke occurred in six years as traced by MODIS satellite data of fires, regional and local atmospheric fine particulate matter (PM2.5), and the amount of potassium (K+) in PM2.5 as a marker of vegetation combustion. Rainwater had elevated K+ and calcium (Ca2+, also associated with wildland fire smoke) in high‐smoke years compared to low‐smoke years, and was the primary route of atmospheric deposition. Similarly, river water in high‐smoke years had elevated concentrations of K+ and Ca2+, with a higher ratio of K+ to Ca2+ compared to low‐smoke years. River concentrations were generally unrelated to river discharge and observed K+ concentrations in high‐smoke and low‐smoke years could be accounted for by atmospheric deposition. Our study provides early evidence that wildland fires affect water quality far beyond the watersheds where they occur. Wildland fires distribute vast quantities of smoke containing nutrients, toxins and microbes and are increasing in North America. Potassium is a routinely‐measured water quality parameter that can act as an indicator of biomass smoke inputs. Further work is needed on the patterns and processes by which wildfire smoke enters water as well as on the consequences for ecosystems and human health.

Negligible Quantities of Particulate Low-Temperature Pyrogenic Carbon Reach the Atlantic Ocean via the Amazon River.

Particulate pyrogenic carbon (PyC) transported by rivers and aerosols, and deposited in marine sediments, is an important part of the carbon cycle. The chemical composition of PyC is temperature dependent and levoglucosan is a source‐specific burning marker used to trace low‐temperature PyC. Levoglucosan associated to particulate material has been shown to be preserved during riverine transport and marine deposition in high‐ and mid‐latitudes, but it is yet unknown if this is also the case for (sub)tropical areas, where 90% of global PyC is produced. Here, we investigate transport and deposition of levoglucosan in suspended and riverbed sediments from the Amazon River system and adjacent marine deposition areas. We show that the Amazon River exports negligible amounts of levoglucosan and that concentrations in sediments from the main Amazon tributaries are not related to long‐term mean catchment‐wide fire activity. Levoglucosan concentrations in marine sediments offshore the Amazon Estuary are positively correlated to total organic content regardless of terrestrial or marine origin, supporting the notion that association of suspended or dissolved PyC to biogenic particles is critical in the preservation of PyC. We estimate that 0.5–10 × 106 g yr−1 of levoglucosan is exported by the Amazon River. This represents only 0.5–10 ppm of the total exported PyC and thereby an insignificant fraction, indicating that riverine derived levoglucosan and low‐temperature PyC in the tropics are almost completely degraded before deposition. Hence, we suggest caution in using levoglucosan as tracer for past fire activity in tropical settings near rivers.

Comparison of Carbonaceous Compounds Emission from the Co-Combustion of Coal and Waste in Boilers Used in Residential Heating in Poland, Central Europe

In this study, the effect of the addition of waste on the emissions from coal co-combustion was investigated. Coal was co-combusted with different additions of medium-density fiberboard and polyethylene terephthalate plastic (10 and 50%), in a low-power boiler (18 W). Polycyclic aromatic hydrocarbons, phenols, alkylphenols, phthalates, and biomass burning markers emissions were determined. Gas chromatography, coupled with a mass spectrometry detector, was used to analyze these compounds in particulate matter and gas phase, after extraction and derivatization. The emissions of polycyclic aromatic hydrocarbons were the highest among all the compounds determined. The total emission of these compounds was 215.1 mg/kg for coal, and 637.7 and 948.3 mg/kg for a 10 and 50% additive of polyethylene terephthalate plastic, respectively. For the 10 and 50% additive of medium-density fiberboard, the total emission was 474.2 and 464.0 mg/kg, respectively. The 50% addition of PET also had the highest emissions of phenols (638.5 mg/kg), alkylphenols (246.5 mg/kg), and phthalates (18.1 mg/kg), except for biomass burning markers, where the emissions were the highest for the 50% addition of medium-density fiberboard (541.3 mg/kg). In our opinion, the obtained results are insufficient for the identification of source apportionment from household heating.