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.

Spatiotemporal Characteristics and Driving Factors of Black Carbon in Augsburg, Germany: Combination of Mobile Monitoring and Street View Images.

The study investigates the spatial pattern of black carbon (BC) at a high spatial resolution in Augsburg, Germany. Sixty two walks were performed to assess the concentrations of equivalent black carbon (eBC), ultraviolet particulate matter (UVPM), and equivalent brown carbon (eBrC) in different seasons and at different times of the day with a mobile platform (i.e., trolley). Along with BC measurements, images of street microenvironments were recorded. Meteorological parameters, including temperature, relative humidity, and wind speed, were monitored. The BC concentrations showed significant spatial heterogeneity and diurnal variations peaking in the morning and at night. The highest BC concentrations were observed near dense traffic. The correlations between BC and street views (buildings, roads, cars, and vegetation) were weak but highly significant. Moreover, meteorological factors also influenced the BC concentration. A model based on street view images and meteorological data was developed to examine the driving factors of the spatial variability of BC concentrations at a higher spatial resolution as different microenvironments based on traffic density. The best results were obtained for UVPM and eBC (71 and 70% explained variability). eBrC (53%), to which other sources besides road traffic can also make significant contributions, is modeled less well.

Air quality intervention during the Nanjing youth olympic games altered PM sources, chemical composition, and toxicological responses.

Ambient particulate matter (PM) is a leading global environmental health risk. Current air quality regulations are based on airborne mass concentration. However, PM from different sources have distinct chemical compositions and varied toxicity. Connections between emission control measures, air quality, PM composition, and toxicity remain insufficiently elucidated. The current study assessed the composition and toxicity of PM collected in Nanjing, China before, during, and after an air quality intervention for the 2014 Youth Olympic Games. A co-culture model that mimics the alveolar epithelium with the associated macrophages was created using A549 and THP-1 cells. These cells were exposed to size-segregated inhalable PM samples. The composition and toxicity of the PM samples were influenced by several factors including seasonal variation, emission sources, and the air quality intervention. For example, we observed a size-dependent shift in particle mass concentrations during the air quality intervention with an emphasized proportion of smaller particles (PM2.5) present in the air. The roles of industrial and fuel combustion and traffic emissions were magnified during the emission control period. Our analyses revealed that the PM samples demonstrated differential cytotoxic potencies at equal mass concentrations between sampling periods, locations, and time of day, influenced by variations in the predominant emission sources. Coal combustion and industrial emissions were the most important sources affecting the toxicological responses and displayed the least variation in emission contributions between the sampling periods. In conclusion, emission control mitigated cytotoxicity and oxidative stress for particles larger than 0.2 µm, but there was inadequate evidence to determine if it was the key factor reducing the harmful effects of PM0.2.

Influence of wood species on toxicity of log-wood stove combustion aerosols: a parallel animal and air-liquid interface cell exposure study on spruce and pine smoke.

BACKGROUND: Wood combustion emissions have been studied previously either by in vitro or in vivo models using collected particles, yet most studies have neglected gaseous compounds. Furthermore, a more accurate and holistic view of the toxicity of aerosols can be gained with parallel in vitro and in vivo studies using direct exposure methods. Moreover, modern exposure techniques such as air-liquid interface (ALI) exposures enable better assessment of the toxicity of the applied aerosols than, for example, the previous state-of-the-art submerged cell exposure techniques. METHODS: We used three different ALI exposure systems in parallel to study the toxicological effects of spruce and pine combustion emissions in human alveolar epithelial (A549) and murine macrophage (RAW264.7) cell lines. A whole-body mouse inhalation system was also used to expose C57BL/6 J mice to aerosol emissions. Moreover, gaseous and particulate fractions were studied separately in one of the cell exposure systems. After exposure, the cells and animals were measured for various parameters of cytotoxicity, inflammation, genotoxicity, transcriptome and proteome. RESULTS: We found that diluted (1:15) exposure pine combustion emissions (PM1 mass 7.7 ± 6.5 mg m- 3, 41 mg MJ- 1) contained, on average, more PM and polycyclic aromatic hydrocarbons (PAHs) than spruce (PM1 mass 4.3 ± 5.1 mg m- 3, 26 mg MJ- 1) emissions, which instead showed a higher concentration of inorganic metals in the emission aerosol. Both A549 cells and mice exposed to these emissions showed low levels of inflammation but significantly increased genotoxicity. Gaseous emission compounds produced similar genotoxicity and a higher inflammatory response than the corresponding complete combustion emission in A549 cells. Systems biology approaches supported the findings, but we detected differing responses between in vivo and in vitro experiments. CONCLUSIONS: Comprehensive in vitro and in vivo exposure studies with emission characterization and systems biology approaches revealed further information on the effects of combustion aerosol toxicity than could be achieved with either method alone. Interestingly, in vitro and in vivo exposures showed the opposite order of the highest DNA damage. In vitro measurements also indicated that the gaseous fraction of emission aerosols may be more important in causing adverse toxicological effects. Combustion aerosols of different wood species result in mild but aerosol specific in vitro and in vivo effects.

Volatile Organic Compounds from Logwood Combustion: Emissions and Transformation under Dark and Photochemical Aging Conditions in a Smog Chamber.

Residential wood combustion (RWC) emits high amounts of volatile organic compounds (VOCs) into ambient air, leading to formation of secondary organic aerosol (SOA), and various health and climate effects. In this study, the emission factors of VOCs from a logwood-fired modern masonry heater were measured using a Proton-Transfer-Reactor Time-of-Flight Mass Spectrometer. Next, the VOCs were aged in a 29 m3 Teflon chamber equipped with UV black lights, where dark and photochemical atmospheric conditions were simulated. The main constituents of the VOC emissions were carbonyls and aromatic compounds, which accounted for 50%-52% and 30%-46% of the detected VOC emission, respectively. Emissions were highly susceptible to different combustion conditions, which caused a 2.4-fold variation in emission factors. The overall VOC concentrations declined considerably during both dark and photochemical aging, with simultaneous increase in particulate organic aerosol mass. Especially furanoic and phenolic compounds decreased, and they are suggested to be the major precursors of RWC-originated SOA in all aging conditions. On the other hand, dark aging produced relatively high amounts of nitrogen-containing organic compounds in both gas and particulate phase, while photochemical aging increased especially the concentrations of certain gaseous carbonyls, particularly acid anhydrides.

Particulate emissions from the combustion of birch, beech, and spruce logs cause different cytotoxic responses in A549 cells.

According to the World Health Organization particulate emissions from the combustion of solid fuels caused more than 110,000 premature deaths worldwide in 2010. Log wood combustion is the most prevalent form of residential biomass heating in developed countries, but it is unknown how the type of wood logs used in furnaces influences the chemical composition of the particulate emissions and their toxicological potential. We burned logs of birch, beech and spruce, which are used commonly as firewood in Central and Northern Europe in a modern masonry heater, and compared them to the particulate emissions from an automated pellet boiler fired with softwood pellets. We determined the chemical composition (elements, ions, and carbonaceous compounds) of the particulate emissions with a diameter of less than 1 µm and tested their cytotoxicity, genotoxicity, inflammatory potential, and ability to induce oxidative stress in a human lung epithelial cell line. The chemical composition of the samples differed significantly, especially with regard to the carbonaceous and metal contents. Also the toxic effects in our tested endpoints varied considerably between each of the three log wood combustion samples, as well as between the log wood combustion samples and the pellet combustion sample. The difference in the toxicological potential of the samples in the various endpoints indicates the involvement of different pathways of toxicity depending on the chemical composition. All three emission samples from the log wood combustions were considerably more toxic in all endpoints than the emissions from the pellet combustion. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1487-1499, 2017.

Untargeted Identification of Wood Type-Specific Markers in Particulate Matter from Wood Combustion.

Residential wood combustion emissions are one of the major global sources of particulate and gaseous organic pollutants. However, the detailed chemical compositions of these emissions are poorly characterized due to their highly complex molecular compositions, nonideal combustion conditions, and sample preparation steps. In this study, the particulate organic emissions from a masonry heater using three types of wood logs, namely, beech, birch, and spruce, were chemically characterized using thermal desorption in situ derivatization coupled to a GCxGC-ToF/MS system. Untargeted data analyses were performed using the comprehensive measurements. Univariate and multivariate chemometric tools, such as analysis of variance (ANOVA), principal component analysis (PCA), and ANOVA simultaneous component analysis (ASCA), were used to reduce the data to highly significant and wood type-specific features. This study reveals substances not previously considered in the literature as meaningful markers for differentiation among wood types.

Toxicity of wood smoke particles in human A549 lung epithelial cells: the role of PAHs, soot and zinc.

Indoor air pollution is associated with increased morbidity and mortality. Specifically, the health impact of emissions from domestic burning of biomass and coal is most relevant and is estimated to contribute to over 4 million premature deaths per year worldwide. Wood is the main fuel source for biomass combustion and the shift towards renewable energy sources will further increase emissions from wood combustion even in developed countries. However, little is known about the constituents of wood smoke and biological mechanisms that are responsible for adverse health effects. We exposed A549 lung epithelial cells to collected wood smoke particles and found an increase in cellular reactive oxygen species as well as a response to bioavailable polycyclic aromatic hydrocarbons. In contrast, cell vitality and regulation of the pro-inflammatory cytokine interleukin-8 were not affected. Using a candidate approach, we could recapitulate WSP toxicity by the combined actions of its constituents soot, metals and PAHs. The soot fraction and metals were found to be the most important factors for ROS formation, whereas the PAH response can be mimicked by the model PAH benzo[a]pyrene. Strikingly, PAHs adsorbed to WSPs were even more potent in activating target gene expression than B[a]P individually applied in suspension. As PAHs initiate multiple adverse outcome pathways and are prominent carcinogens, their role as key pollutants in wood smoke and its health effects warrants further investigation. The presented results suggest that each of the investigated constituents soot, metals and PAHs are major contributors to WSP toxicity. Mitigation strategies to prevent adverse health effects of wood combustion should therefore not only aim at reducing the emitted soot and PAHs but also the metal content, through the use of more efficient combustion appliances, and particle precipitation techniques, respectively.

Differential proteomic analysis of mouse macrophages exposed to adsorbate-loaded heavy fuel oil derived combustion particles using an automated sample-preparation workflow.

Ship diesel combustion particles are known to cause broad cytotoxic effects and thereby strongly impact human health. Particles from heavy fuel oil (HFO) operated ships are considered as particularly dangerous. However, little is known about the relevant components of the ship emission particles. In particular, it is interesting to know if the particle cores, consisting of soot and metal oxides, or the adsorbate layers, consisting of semi- and low-volatile organic compounds and salts, are more relevant. We therefore sought to relate the adsorbates and the core composition of HFO combustion particles to the early cellular responses, allowing for the development of measures that counteract their detrimental effects. Hence, the semi-volatile coating of HFO-operated ship diesel engine particles was removed by stepwise thermal stripping using different temperatures. RAW 264.7 macrophages were exposed to native and thermally stripped particles in submersed culture. Proteomic changes were monitored by two different quantitative mass spectrometry approaches, stable isotope labeling by amino acids in cell culture (SILAC) and dimethyl labeling. Our data revealed that cells reacted differently to native or stripped HFO combustion particles. Cells exposed to thermally stripped particles showed a very differential reaction with respect to the composition of the individual chemical load of the particle. The cellular reactions of the HFO particles included reaction to oxidative stress, reorganization of the cytoskeleton and changes in endocytosis. Cells exposed to the 280 °C treated particles showed an induction of RNA-related processes, a number of mitochondria-associated processes as well as DNA damage response, while the exposure to 580 °C treated HFO particles mainly induced the regulation of intracellular transport. In summary, our analysis based on a highly reproducible automated proteomic sample-preparation procedure shows a diverse cellular response, depending on the soot particle composition. In particular, it was shown that both the molecules of the adsorbate layer as well as particle cores induced strong but different effects in the exposed cells.

The composition of cigarette smoke determines inflammatory cell recruitment to the lung in COPD mouse models.

COPD (chronic obstructive pulmonary disease) is caused by exposure to toxic gases and particles, most often CS (cigarette smoke), leading to emphysema, chronic bronchitis, mucus production and a subsequent decline in lung function. The disease pathogenesis is related to an abnormal CS-induced inflammatory response of the lungs. Similar to active (mainstream) smoking, second hand (sidestream) smoke exposure severely affects respiratory health. These processes can be studied in vivo in models of CS exposure of mice. We compared the acute inflammatory response of female C57BL/6 mice exposed to two concentrations [250 and 500 mg/m3 TPM (total particulate matter)] of sidestream and mainstream CS for 3 days and interpreted the biological effects based on physico-chemical differences in the gas and particulate phase composition of CS. BAL (bronchoalveolar lavage fluid) was obtained to perform differential cell counts and to measure cytokine release. Lung tissue was used to determine mRNA and protein expression of proinflammatory genes and to assess tissue inflammation. A strong acute inflammatory response characterized by neutrophilic influx, increased cytokine secretion [KC (keratinocyte chemoattractant), TNF-α (tumour necrosis factor α), MIP-2 (macrophage inflammatory protein 2), MIP-1α and MCP-1 (monocyte chemoattractant protein-1)], pro-inflammatory gene expression [KC, MIP-2 and MMP12 (matrix metalloproteinase 12)] and up-regulated GM-CSF (granulocyte macrophage colony-stimulating factor) production was observed in the mainstream model. After sidestream exposure there was a dampened inflammatory reaction consisting only of macrophages and diminished GM-CSF levels, most likely caused by elevated CO concentrations. These results demonstrate that the composition of CS determines the dynamics of inflammatory cell recruitment in COPD mouse models. Different initial inflammatory processes might contribute to COPD pathogenesis in significantly varying ways, thereby determining the outcome of the studies.

[Allergies in the light of global environmental changes]. / Allergien im Lichte globaler Umweltveränderungen.

BACKGROUND: The increase in allergies began worldwide with the onset of the Great Acceleration. Environmental pollution and climate change now threaten to cancel out decades of success in health research. OBJECTIVE: A summary of environmental influences is provided, which not only shows the significant increase in the prevalence of allergies worldwide but also that of noncommunicable diseases. The effects of the climate crisis on allergies and the multifactorial and interfunctional relationships with other environmental changes are described in detail. MATERIAL AND METHODS: In order to obtain an overview of the possible effects of global environmental changes on allergies, a wide range of literature was evaluated and the study results were prepared and summarized. RESULTS: A large number of allergens are influencing the human exposome on a daily basis. These allergens are triggered by environmental changes, such as air pollution in the ambient air and indoors, chemicals in everyday objects or residues in food. People are sensitized by the interaction of allergens and pollutants. CONCLUSION: The prevalence of allergies is stagnating in industrialized countries. This is probably just the calm before the storm. The accelerating effects of global warming could make pollen and air pollutants even more aggressive in the future. Urgent action is therefore needed to minimize environmental pollution and mitigate climate change.

Molecular composition of fresh and aged aerosols from residential wood combustion and gasoline car with modern emission mitigation technology.

Emissions from road traffic and residential heating contribute to urban air pollution. Advances in emission reduction technologies may alter the composition of emissions and affect their fate during atmospheric processing. Here, emissions of a gasoline car and a wood stove, both equipped with modern emission mitigation technology, were photochemically aged in an oxidation flow reactor to the equivalent of one to five days of photochemical aging. Fresh and aged exhausts were analyzed by ultrahigh resolution mass spectrometry. The gasoline car equipped with a three-way catalyst and a gasoline particle filter emitted minor primary fine particulate matter (PM2.5), but aging led to formation of particulate low-volatile, oxygenated and highly nitrogen-containing compounds, formed from volatile organic compounds (VOCs) and gases incl. NOx, SO2, and NH3. Reduction of the particle concentration was also observed for the application of an electrostatic precipitator with residential wood combustion but with no significant effect on the chemical composition of PM2.5. Comparing the effect of short and medium photochemical exposures on PM2.5 of both emission sources indicates a similar trend for formation of new organic compounds with increased carbon oxidation state and nitrogen content. The overall bulk compositions of the studied emission exhausts became more similar by aging, with many newly formed elemental compositions being shared. However, the presence of particulate matter in wood combustion results in differences in the molecular properties of secondary particles, as some compounds were preserved during aging.

Chemical Fingerprinting of Biomass Burning Organic Aerosols from Sugar Cane Combustion: Complementary Findings from Field and Laboratory Studies.

Agricultural fires are a major source of biomass-burning organic aerosols (BBOAs) with impacts on health, the environment, and climate. In this study, globally relevant BBOA emissions from the combustion of sugar cane in both field and laboratory experiments were analyzed using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. The derived chemical fingerprints of fresh emissions were evaluated using targeted and nontargeted evaluation approaches. The open-field sugar cane burning experiments revealed the high chemical complexity of combustion emissions, including compounds derived from the pyrolysis of (hemi)cellulose, lignin, and further biomass, such as pyridine and oxime derivatives, methoxyphenols, and methoxybenzenes, as well as triterpenoids. In comparison, laboratory experiments could only partially model the complexity of real combustion events. Our results showed high variability between the conducted field and laboratory experiments, which we, among others, discuss in terms of differences in combustion conditions, fuel composition, and atmospheric processing. We conclude that both field and laboratory studies have their merits and should be applied complementarily. While field studies under real-world conditions are essential to assess the general impact on air quality, climate, and environment, laboratory studies are better suited to investigate specific emissions of different biomass types under controlled conditions.

Processing of carbon-reinforced construction materials releases PM2.5 inducing inflammation and (secondary) genotoxicity in human lung epithelial cells and fibroblasts.

Building demolition following domestic fires or abrasive processing after thermal recycling can release particles harmful for the environment and human health. To mimic such situations, particles release during dry-cutting of construction materials was investigated. A reinforcement material consisting of carbon rods (CR), carbon concrete composite (C³) and thermally treated C³ (ttC³) were physicochemically and toxicologically analyzed in monocultured lung epithelial cells, and co-cultured lung epithelial cells and fibroblasts at the air-liquid interface. C³ particles reduced their diameter to WHO fibre dimensions during thermal treatment. Caused by physical properties or by polycyclic aromatic hydrocarbons and bisphenol A found in the materials, especially the released particles of CR and ttC³ induced an acute inflammatory response and (secondary) DNA damage. Transcriptome analysis indicated that CR and ttC³ particles carried out their toxicity via different mechanisms. While ttC³ affected pro-fibrotic pathways, CR was mostly involved in DNA damage response and in pro-oncogenic signaling.

Systems toxicology of complex wood combustion aerosol reveals gaseous carbonyl compounds as critical constituents.

Epidemiological studies identified air pollution as one of the prime causes for human morbidity and mortality, due to harmful effects mainly on the cardiovascular and respiratory systems. Damage to the lung leads to several severe diseases such as fibrosis, chronic obstructive pulmonary disease and cancer. Noxious environmental aerosols are comprised of a gas and particulate phase representing highly complex chemical mixtures composed of myriads of compounds. Although some critical pollutants, foremost particulate matter (PM), could be linked to adverse health effects, a comprehensive understanding of relevant biological mechanisms and detrimental aerosol constituents is still lacking. Here, we employed a systems toxicology approach focusing on wood combustion, an important source for air pollution, and demonstrate a key role of the gas phase, specifically carbonyls, in driving adverse effects. Transcriptional profiling and biochemical analysis of human lung cells exposed at the air-liquid-interface determined DNA damage and stress response, as well as perturbation of cellular metabolism, as major key events. Connectivity mapping revealed a high similarity of gene expression signatures induced by wood smoke and agents prompting DNA-protein crosslinks (DPCs). Indeed, various gaseous aldehydes were detected in wood smoke, which promote DPCs, initiate similar genomic responses and are responsible for DNA damage provoked by wood smoke. Hence, systems toxicology enables the discovery of critical constituents of complex mixtures i.e. aerosols and highlights the role of carbonyls on top of particulate matter as an important health hazard.

Aerosol emissions from a marine diesel engine running on different fuels and effects of exhaust gas cleaning measures.

The emissions of marine diesel engines have gained both global and regional attentions because of their impact on human health and climate change. To reduce ship emissions, the International Maritime Organization capped the fuel sulfur content of marine fuels. Consequently, either low-sulfur fuels or additional exhaust gas cleaning devices for the reduction in sulfur dioxide (SO2) emissions became mandatory. Although a wet scrubber reduces the amount of SO2 significantly, there is still a need to consider the reduction in particle emissions directly. We present data on the particle removal efficiency of a scrubber regarding particle number and mass concentration with different marine fuel types, marine gas oil, and two heavy fuel oils (HFOs). An open-loop sulfur scrubber was installed in the exhaust line of a marine diesel test engine. Fine particulate matter was comprehensively characterized in terms of its physical and chemical properties. The wet scrubber led up to a 40% reduction in particle number, whereas a reduction in particle mass emissions was not generally determined. We observed a shift in the size distribution by the scrubber to larger particle diameters when the engine was operated on conventional HFOs. The reduction in particle number concentrations and shift in particle size were caused by the coagulation of soot particles and formation/growing of sulfur-containing particles. Combining the scrubber with a wet electrostatic precipitator as an additional abatement system showed a reduction in particle number and mass emission factors by >98%. Therefore, the application of a wet scrubber for the after-treatment of marine fuel oil combustion will reduce SO2 emissions, but it does not substantially affect the number and mass concentration of respirable particulate matters. To reduce particle emission, the scrubber should be combined with additional abatement systems.

A comparative study of persistent DNA oxidation and chromosomal instability induced in vitro by oxidizers and reference airborne particles.

Adverse health effects driven by airborne particulate matter (PM) are mainly associated with reactive oxygen species formation, pro-inflammatory effects, and genome instability. Therefore, a better understanding of the underlying mechanisms is needed to evaluate health risks caused by exposure to PM. The aim of this study was to compare the genotoxic effects of two oxidizing agents (menadione and 3-chloro-1,2-propanediol) with three different reference PM (fine dust ERM-CZ100, urban dust SRM1649, and diesel PM SRM2975) on monocytic THP-1 and alveolar epithelial A549 cells. We assessed DNA oxidation by measuring the oxidized derivative 8-hydroxy-2'-deoxyguanosine (8-OHdG) following short and long exposure times to evaluate the persistency of oxidative DNA damage. Cytokinesis-block micronucleus cytome assay was performed to assess chromosomal instability, cytostasis, and cytotoxicity. Particles were characterized by inductively coupled plasma mass spectrometry in terms of selected elemental content, the release of ions in cell medium and the cellular uptake of metals. PM deposition and cellular dose were investigated by a spectrophotometric method on adherent A549 cells. The level of lipid peroxidation was evaluated via malondialdehyde concentration measurement. Despite differences in the tested concentrations, deposition efficiency, and lipid peroxidation levels, all reference PM samples caused oxidative DNA damage to a similar extent as the two oxidizers in terms of magnitude but with different oxidative DNA damage persistence. Diesel SRM2975 were more effective in inducing chromosomal instability with respect to fine and urban dust highlighting the role of polycyclic aromatic hydrocarbons derivatives on chromosomal instability. The persistence of 8-OHdG lesions strongly correlated with different types of chromosomal damage and revealed distinguishing sensitivity of cell types as well as specific features of particles versus oxidizing agent effects. In conclusion, this study revealed that an interplay between DNA oxidation persistence and chromosomal damage is driving particulate matter-induced genome instability.

Genotoxic and inflammatory effects of spruce and brown coal briquettes combustion aerosols on lung cells at the air-liquid interface.

Solid fuel usage in residential heating and cooking is one of the largest sources of ambient and indoor air particulate matter, which causes adverse effects on the health of millions of peoples worldwide. Emissions from solid fuel combustion, such as biomass or coal, are detrimental to health, but toxicological responses are largely unknown. In the present study, we compared the toxicological responses regarding cytotoxicity, inflammation and genotoxicity of spruce (SPR) and brown coal briquette (BCB) combustion aerosols on human alveolar epithelial cells (A549) as well as a coculture of A549 and differentiated human monocytic cells (THP-1) into macrophages exposed at the air-liquid interface (ALI). We included both the high emissions from the first hour and moderate emissions from the third hour of the batch combustion experiment in one ALI system, whereas, in the second ALI system, we exposed the cells during the whole 4-hour combustion experiment, including all combustion phases. Physico-chemical properties of the combustion aerosol were analysed both online and offline. Both SPR and BCB combustion aerosols caused mild cytotoxic but notable genotoxic effects in co-cultured A549 cells after one-hour exposure. Inflammatory response analysis revealed BCB combustion aerosols to cause a mild increase in CXCL1 and CXCL8 levels, but in the case of SPR combustion aerosol, a decrease compared to control was observed.

Effect of Atmospheric Aging on Soot Particle Toxicity in Lung Cell Models at the Air-Liquid Interface: Differential Toxicological Impacts of Biogenic and Anthropogenic Secondary Organic Aerosols (SOAs).

BACKGROUND: Secondary organic aerosols (SOAs) formed from anthropogenic or biogenic gaseous precursors in the atmosphere substantially contribute to the ambient fine particulate matter [PM ≤2.5µm in aerodynamic diameter (PM2.5)] burden, which has been associated with adverse human health effects. However, there is only limited evidence on their differential toxicological impact. OBJECTIVES: We aimed to discriminate toxicological effects of aerosols generated by atmospheric aging on combustion soot particles (SPs) of gaseous biogenic (ß-pinene) or anthropogenic (naphthalene) precursors in two different lung cell models exposed at the air-liquid interface (ALI). METHODS: Mono- or cocultures of lung epithelial cells (A549) and endothelial cells (EA.hy926) were exposed at the ALI for 4 h to different aerosol concentrations of a photochemically aged mixture of primary combustion SP and ß-pinene (SOAßPIN-SP) or naphthalene (SOANAP-SP). The internally mixed soot/SOA particles were comprehensively characterized in terms of their physical and chemical properties. We conducted toxicity tests to determine cytotoxicity, intracellular oxidative stress, primary and secondary genotoxicity, as well as inflammatory and angiogenic effects. RESULTS: We observed considerable toxicity-related outcomes in cells treated with either SOA type. Greater adverse effects were measured for SOANAP-SP compared with SOAßPIN-SP in both cell models, whereas the nano-sized soot cores alone showed only minor effects. At the functional level, we found that SOANAP-SP augmented the secretion of malondialdehyde and interleukin-8 and may have induced the activation of endothelial cells in the coculture system. This activation was confirmed by comet assay, suggesting secondary genotoxicity and greater angiogenic potential. Chemical characterization of PM revealed distinct qualitative differences in the composition of the two secondary aerosol types. DISCUSSION: In this study using A549 and EA.hy926 cells exposed at ALI, SOA compounds had greater toxicity than primary SPs. Photochemical aging of naphthalene was associated with the formation of more oxidized, more aromatic SOAs with a higher oxidative potential and toxicity compared with ß-pinene. Thus, we conclude that the influence of atmospheric chemistry on the chemical PM composition plays a crucial role for the adverse health outcome of emissions. https://doi.org/10.1289/EHP9413.