Smoke Research Articles

Повышение экологической безопасности коптильного производства в соответствии с принципами устойчивого развития

The work is devoted to the study of the physico-chemical characteristics of wood smoke used in the production of hot and cold smoked fish. The dispersion composition of wood smoke is determined depending on the temperature in the smoke formation zone and the excess air coefficient. The content of the main smoky components and polyaromatic hydrocarbons (PAHs) in the particles of the dispersed phase of wood smoke of various sizes has been established. A model of changing the dispersed composition of smoky smoke in the process of hot smoking is proposed. Theoretical calculations based on the proposed models of changes in the dispersed composition have been experimentally confirmed.
 Physico-chemical and statistical research methods were used in the work.

Formation of secondary organic material from gaseous precursors in wood smoke

ABSTRACT The apportionment of the contribution of wood smoke emitted particles to the total concentration of particulate matter in a region has been greatly aided by the development of new analytical methods. These analytical methods quantitatively determine organic marker compounds unique to wood combustion such as levoglucosan and dehydroabietic acid. These markers have generally been determined in 24-hour averaged samples. We have developed an instrument based on the collection of particles on an inert filter, desorption of the organic material in an inert atmosphere with subsequent GC separation and MS detection of the desorbed compounds. The GC-MS Organic Aerosol Monitor (OAM) instrument has been used in three field studies. An unexpected finding from these studies was the quantification of the contribution of secondary organic aerosols from gases present in wood smoke in addition to primary wood smoke emitted particles. The identification of this secondary material was made possible by the collection of hourly averaged data that allowed for the time patterns of black carbon, organic material, and wood smoke marker compounds to be included and compared in a Positive Matrix Factorization (PMF) analysis. Most of the organic markers associated with wood smoke (levoglucosan, stearic acid and dehydroabietic acid) are associated with primary wood smoke emissions, but a fraction of the levoglucosan and stearic acid are also associated with secondary organic material formed from gaseous precursors in wood smoke. Additionally, this secondary material was shown to be present in each in of the three urban area where wood smoke burning occurs. There is a need for additional studies to better understand the contribution of secondary particulate formation from both urban and wildfires. Implications: This paper presents results from three field studies which show that in addition to the formation of primary particulate matter from the combustion of wood smoke and secondary particulate matter is also formed from the gaseous compounds emitted with the wood smoke. This material is identified in the studies of wood combustion reported here by the identification and quantification of specific organic marker compounds related to wood combustion and is shown to and represents a contributor nearly as large as the primary emitted material and better quantifying the impact of wood combustion on airborne fine particulate matter.

Wildfire Smoke Exposure during Pregnancy: A Review of Potential Mechanisms of Placental Toxicity, Impact on Obstetric Outcomes, and Strategies to Reduce Exposure.

Climate change is accelerating the intensity and frequency of wildfires globally. Understanding how wildfire smoke (WS) may lead to adverse pregnancy outcomes and alterations in placental function via biological mechanisms is critical to mitigate the harms of exposure. We aim to review the literature surrounding WS, placental biology, biological mechanisms underlying adverse pregnancy outcomes as well as interventions and strategies to avoid WS exposure in pregnancy. This review includes epidemiologic and experimental laboratory-based studies of WS, air pollution, particulate matter (PM), and other chemicals related to combustion in relation to obstetric outcomes and placental biology. We summarized the available clinical, animal, and placental studies with WS and other combustion products such as tobacco, diesel, and wood smoke. Additionally, we reviewed current recommendations for prevention of WS exposure. We found that there is limited data specific to WS; however, studies on air pollution and other combustion sources suggest a link to inflammation, oxidative stress, endocrine disruption, DNA damage, telomere shortening, epigenetic changes, as well as metabolic, vascular, and endothelial dysregulation in the maternal-fetal unit. These alterations in placental biology contribute to adverse obstetric outcomes that disproportionally affect the most vulnerable. Limiting time outdoors, wearing N95 respirator face masks and using high quality indoor air filters during wildfire events reduces exposure to related environmental exposures and may mitigate morbidities attributable to WS.

Lung Cancer and Women

Lung cancer is a current public health problem, as its incidence continues to rise, especially in women. The aim of the study was to evaluate epidemiological, clinical and histological profile of women’s lung cancer. A retrospective study including women patients with a confirmed lung cancer followed at the Pneumology Department of University Hospital Center Mohammed VI of Marrakesh in Morocco between January 2016 and june 2021. 34 cases were included in the study. The average age of patients was 58 years. Active smoking was present in 15.4% and passive smoking in 40% of patients. Wood smoke exposure was found in 57.7% of patients. Intraparenchymal opacities were the most frequent radiological feature in 58% of cases. Chest CT scans, performed in all women, showed an intraparenchymal mass in 78% of cases. Histological confirmation was obtained by bronchial fibroscopy (56%), trans-parietal biopsy (28%), and pleural biopsy (16%). The most frequent histological type was adenocarcinoma (56.1%), followed by squamous cell carcinoma (36.3%) and small cell carcinoma (7.6%). The stage of the disease is metastatic in 51% of cases. The most frequent metastatic locations were pleura (38.5%), bone (23%), brain (15%), and liver (7.6%).

Matrix Metalloproteinases and Stress Hormones in Lung Cancer Progression.

Several matrix metalloproteinases (MMPs) and psychological stress are associated with poor cancer prognosis. The current work goal was to determine MMPs' and stress hormones' blood concentrations from lung adenocarcinoma (LAC) patients. Patients were divided into the following groups: tobacco smokers (TS), wood smoke-exposed (W), passive smokers (PS), TS exposed to wood smoke (TW), and patients with no recognizable risk factor (N). MMPs, tissue inhibitors of metalloproteinases (TIMPs), adrenaline, noradrenaline, and cortisol blood concentrations were measured by ELISA. Zymography and Western blot assays were performed to determine MMP-2 and MMP-9 active and latent forms. MMP-2, MMP-3, MMP-9, and TIMP-1 blood concentrations, and MMP-9 gelatinase activity were augmented, while MMP-12, MMP-14, and TIMP-2 were diminished in LAC patients. Cortisol was increased in LAC samples. Adrenaline concentrations were higher in W, TS, and TW, and noradrenaline was increased in W and N groups. Positive correlations were observed among cortisol and TIMP-1 (rs = 0.392) and TIMP-2 (rs = 0.409) in the W group and between noradrenaline and MMP-2 (rs = 0.391) in the N group. MMPs' blood concentration increments can be considered as lung cancer progression markers. Although stress hormones were also augmented, only weak correlations were observed between them and MMPs and TIMPs.

Mapping the mechanistic evidence of wood smoke and wildfire studies in humans

Background and Aim Wood smoke is a complex mixture of gases, chemicals, and fine particles generated by wood-burning and wildfires. We are conducting a cancer hazard evaluation of wood smoke for possible listing in the U.S. Report on Carcinogens. The database of cancer epidemiology studies for exposure to wood smoke, but not wildfire, is adequate to conduct an evaluation. As mechanistic evidence may inform the overall hazard evaluation, especially for wildfires, we mapped the published evidence by biomarkers for the key characteristic of carcinogens (KCC), focusing here on studies in exposed humans. Methods We systematically searched three bibliographic databases for relevant biomarker studies on wildfire and wood smoke exposure. For selected studies reporting on the three most common KCCs (genotoxicity, oxidative stress, immune biomarkers), we extracted information including specific KCC biomarkers (e.g., mutations), results, study design, and population, and presented the data in an interactive evidence map. Results Wood smoke: Most human studies (26) found positive associations with KCCs, consistent with the >70 non-human studies (in vitro and in vivo). Inflammation, inflammatory cytokines, and lipid peroxidation were the most common KCCs in humans. The studies were primarily intervention or cross-sectional in populations cooking or heating with wood or randomized studies of controlled exposure. Wildfires: Human studies (15) were largely positive for immune biomarkers but inconsistent for genotoxicity and oxidative stress, whereas non-human studies (17) were generally positive for all endpoints. Most studies measured KCCs in firefighters (13) before or after exposure (e.g., work shift or natural wildfire event). Conclusions Wildfires are increasing in frequency and intensity due to climate change, and exposure to wood smoke remains a worldwide concern. This mechanistic evidence will help inform the cancer hazard evaluations of these exposures. Ongoing risk-of-bias evaluations may explain heterogeneity in human wildfire studies. Keywords Wood smoke, wildfires, biomarkers, exposed humans

Exposure to indoor wood-burning stoves and fireplaces and risk of lung cancer among Sister Study participants

Background and Aim: Epidemiological evidence from case-control studies has identified exposure to household combustion of biomass fuel (primarily wood) as a probable lung carcinogen. However, few studies have been conducted in the United States, where indoor wood-burning and usage patterns differ. We examined the association of exposure to indoor wood smoke from fireplaces and stoves with incident lung cancer in U.S. women. Methods: 50,399 women were studied in the U.S.-based prospective Sister Study cohort (recruited 2003-2009) who answered baseline exposure information and did not have lung cancer before enrollment. At baseline, women reported their frequency of use of wood-burning stoves and/or fireplaces in their longest-lived adult residence. Cox regression was used to estimate adjusted hazard ratios (HRadj) and 95% confidence intervals (CI) for the association between indoor wood-burning fireplace/stove use and incident lung cancer. Results: During an average of 11.3 years of follow-up, 520 lung cancer cases were diagnosed. Overall, 62.2% of the study population reported the presence of an indoor wood-burning fireplace/stove at their longest-lived adult residence. Compared to those without a wood-burning fireplace/stove, an elevated risk of lung cancer was observed in women who used their wood-burning fireplace/stove ≥30 days/year (HRadj = 1.20; 95% CI = 0.94, 1.52; p-for-trend=0.09). Associations were more pronounced in never smokers, with elevated HRs observed in women reporting use both 1-29 days/year (HRadj = 1.87; 95% CI = 1.07, 3.28) and ≥30 days/year (HRadj = 1.69; 95% CI = 0.92, 3.11). Findings were stronger among women who were younger, had less educational attainment and lived in urban settings. Conclusions: Our prospective analysis of a cohort of U.S. women found that frequent use of wood-burning indoor fireplaces/stoves was associated with incident lung cancer, consistent with earlier findings. Keywords: Wood Smoke; Lung Cancer; Women; Respiratory Diseases

Application of co-created citizen science in environmental epidemiology

Background and aim: Scientists and scientific institutions are adopting more extensive participatory models, hoping to bridge the gap between institutionalized science and society. Though citizen science has become more common in environmental monitoring, it is seldom utilized in environmental epidemiology. In the Cities-Health study, we co-created epidemiological studies with citizens in five European cities. The aim of this paper is to provide methodological insight into the application of co-created citizen science strategies in environmental epidemiology. Methods: We applied the CitieS-Health framework for citizen science, which is a framework that allows citizens to be involved throughout all the phases of the research projects, in five environmental epidemiology studies. Studies covered diverse environmental issues (e.g. urban air pollution, wood smoke, noise) in Spain, Italy, the Netherlands, Slovenia and Lithuania. Among other aspects this included co-identifying the research question, co-designing and submitting the research protocol for ethical clearance, co-collecting data, co-analyzing data, co-authoring scientific articles and further communication of results to diverse audiences. Results: Together with citizens, we were able to design and conduct environmental epidemiology studies reflecting their concerns and knowledge. Involvement of citizens occurred in all of the research phases with different levels of participation depending on the needs and characteristics of each pilot. Examples of citizens’ impact on research done in the Dutch pilot study was the inclusion of an additional health outcome, exposure period analysis and interpretation of exposure settings. Online communication was a major component, affecting the number of citizens involved, but also study quality. Citizens remained interested and invested time throughout the duration of the projects, some even becoming pilot "community champions”. Conclusions: Integration of citizen science in environmental epidemiology is feasible and has the potential to improve the quality of research and civic trust in research and results. Keywords: Co- creation, citizen science, Participatory Epidemiology

Systematic review and meta-analysis of studies of exposure to wood smoke from cooking or heating and lung cancer

Systematic review and meta-analysis of studies of exposure to wood smoke from cooking or heating and lung cancer

Association between woodsmoke and respiratory health: A Dutch panel study

Background and aim: In the Netherlands household fireplaces are responsible for burning about 1 billion kilograms of wood per year, emitting a significant amount of woodsmoke. Little is known about the respiratory health effects associated with the level of woodsmoke exposure present in the Netherlands. Thus, our aim was to investigate the short-term changes in lung function, respiratory symptoms and medication use associated with short-term changes in woodsmoke exposures in citizens with and without COPD/asthma. The study was co-created with citizens. Methods: We conducted a panel study with repeated observations in 46 adults (11 asthma/COPD) between February and May 2021 in four Dutch cities. Participants were asked to document symptoms and medication use in a daily diary and conduct daily home spirometry measurements in the morning and evening. Woodsmoke exposure was characterized by measuring various exposures at central sites in each study location set-up specifically for the study, and individual woodsmoke perception (smell) recorded in the daily diaries. The association between woodsmoke and health was analyzed using linear and logistic regression, adjusting for time-varying confounders and repeated observations. Results: We found significant positive associations between the specific wood smoke marker levoglucosan and shortness of breath during rest (OR 1.15 (95%CI 1.01, 1.32) per IQR increment for previous day exposure) and extra medication use (OR 1.19 (95%CI 1.07, 1.33) per IQR increment for current day exposure). We found weak associations between woodsmoke and nasal symptoms, and no consistent association with either morning or evening lung function measurements. The associations with levoglucosan remained after the inclusion of generic PM2.5 as a co-pollutant in the statistical models. Conclusion: People experienced more shortness of breath at rest, nasal symptoms and used more medication on days with higher levels of outdoor woodsmoke exposure. Keywords: Woodsmoke, Levoglucosan, Respiratory health, Panel study.

Enfermedad pulmonar intersticial difusa y su relación con el humo de leña estimado por un índice de exposición anual IEAHL

Introduction: lung diseases that affect the interstice have multicausal etiology where exposure to biomass using firewood as a fuel source in food preparation continues to be rooted in our communities. Objective: to describe an index that quantifies the risk of developing diffuse interstitial lung disease, ILD, in relation to the degree of exposure to wood smoke, according to the number of main meals cooked with said method, multiplied by the number of years exposed, IEAHL. Material and Method: study of cases and controls. We analyzed 37 cases of ILD patients and their relationship to wood smoke based on our own proposal for an annual exposure index and 33 controls admitted for surgical treatment in general surgery, with ethnic characteristics, age and sociocultural status similar to the cases studied. For IEAHL, the range 50 to 99 was chosen for moderate degree exposure and more than 100 severe degree. Results: severe (OR=26 95%CI 2.63 – 270) and moderate (OR=9.6795%CI 1.32 – 70.97) IEAHL are associated with ILD type non-specific interstitial pneumonitis (NSIP), while usual interstitial pneumonitis (UIP) only to a severe degree (OR=20 95%CI 2.04 – 196.03). Conclusion: the index of annual exposure to wood smoke IEAHL is presented as an objective and simple alternative to determine the risk of suffering from diffuse interstitial lung diseases and was found to be associated with NSIP and UIP, thus establishing a relationship between severity of exposure and ILD development.

Influence of Smoking on the Volatiles Profile of Arius parkii, Cyprinus carpio and Three Selected Sciaenidae Family Fish Species

ABSTRACT The impact of smoking on the volatile components of five fish species via a two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOF-MS) was studied. Among these, C. carpio was found to be the most susceptible to deterioration. The experimental results affirmed that: fresh fish flavors are delicate, aroma/odor production via smoking depends on the fish specie involved and that industrial processes with heat application may affect fresh fish odor-active components. It further indicated the possibility of smoking to bring about the contribution of volatile compounds from wood smoke, production of off-flavors and/or increase the levels of some harmful compounds in fish.

Local and regional sources of urban ambient PM2.5 exposures in Calgary, Canada

Ambient fine size fraction particulate matter (PM2.5) sources in the western Canada city of Calgary, Alberta were identified and their contributions quantified for 2015–2019 based on elemental and ion composition data from sampling at a central monitoring site and the US Environmental Protection Agency Positive Matrix Factorization (v5.0) receptor model. Meaningful source apportionment results were obtained by using reconstructed PM2.5 mass and an estimated unmeasured mass in absence of carbonaceous component measurements. Auxiliary analyses identified source regions. Identified source types and average contribution to PM2.5 were secondary organic aerosol (24%), wood smoke (16%), soil/crustal matter (15%), traffic/rail (14%), particulate sulfate (13%), particulate nitrate (10%), and road salt/aged road salt (9% combined). Calgary PM2.5 contributions of secondary organic aerosol, particulate sulfate, and traffic/rail sources were similar to the next-nearest western city of Edmonton while particulate nitrate contributions were lower, wood smoke impacts greater and other factors showed greater inter-city differences. Secondary PM2.5 contributions in Calgary were consistent with estimates for medium and large cities in central Canada for SOA and particulate nitrate but lower for particulate sulfate. Primary wood smoke PM2.5 contributions were consistent with other Canadian cities and confirmed strong influence of winter season biomass burning. Combined on-road vehicle and rail transportation activity were found to contribute comparably more to ambient PM2.5 in Calgary than in central Canadian cities. Soil/crustal re-suspension/transport and intensive winter-time use of road salts were also important local PM2.5 sources. Several factors were characterized by local sources (traffic/rail, soil/crustal matter, road salt, aged road salt, wood smoke) with episodic regional source contributions (wood smoke, soil/crustal matter) and secondary aerosol factors (SOA, particulate sulfate, particulate nitrate) also demonstrated influence from local sources alongside regional source contributions, indicating that Calgary ambient PM2.5 concentrations are likely strongly influenced by local source emissions. These findings present positive opportunities for multiple air quality management and source mitigation strategies, including at the local/municipal level.

Genetic polymorphism impact superoxide dismutase and glutathione peroxidase activity in charcoal workers.

Incomplete combustion of wood releases toxic chemicals. Exposure to these chemicals during charcoal production can modulate redox status of cellular system which may further lead to genomic instability and of antioxidant enzymes. Genetic polymorphism may alter the functioning properties of these enzymes and modulate the response to oxidative stress. In this study, we analyzed the link between genetic polymorphism and enzyme activity for antioxidant enzymes: MnSOD and GPx-1 in charcoal workers and control population. This study included 77 charcoal workers and 79 demographically matched healthy control subjects. This association was studied using multiple linear regression, adjusted for confounding factors viz. age, consumption habits and exposure duration. SOD activity was lower for TT genotype (3.47 ± 0.66; 5.92 ± 1.08) versus CC genotype (3.47 ± 0.66; 6.67 ± 1.60) in control and charcoal workers respectively. Significant lower GPx-1 activity was found in leu/leu genotype (7.25 ± 0.38; 3.59 ± 0.57) when compared to pro/pro genotype (7.78 ± 0.59; 4.28 ± 0.71) and pro/leu genotype (8.48 ± 0.34; 4.30 ± 0.76) in control population and charcoal workers respectively. A significant difference in the levels of 1-Hydroxypyrene (biomarker of exposure) and SOD and GPx-1 activity (biomarkers of oxidative stress) was evident in exposed group in comparison to the control one. Collectively, our findings suggested that PAH influenced the mode of action of SOD and GPx-1 which were impacted by polymorphism in SOD and GPx-1 gene. Hence, polymorphism of MnSOD and GPx-1 genes were found to play a modulatory role in human susceptibility to oxidative damage induced by wood smoke in charcoal workers.

Development of an Integrated Platform to Assess the Physicochemical and Toxicological Properties of Wood Combustion Particulate Matter.

Wood burning contributes to indoor and ambient particulate matter (PM) pollution and has been associated with increased morbidity and mortality. Here, we present an integrated methodology that allows to generate, sample, and characterize wood smoke derived from different moisture contents and representative combustion conditions using pine wood as a model. Flaming, smoldering, and incomplete combustion were assessed for low-moisture pine, whereas both low-moisture pine and high-moisture pine were investigated under flaming conditions. Real-time monitoring of carbon monoxide, volatile organic compounds, and aerosol number concentration/size in wood smoke was performed. The PM was size-fractionated, sampled, and characterized for elemental/organic carbon, organic functional groups, and inorganic elements. Bioactivity of PM was assessed by measuring the sterile alpha motif (SAM) pointed domain containing ETS (E-twenty-six) transcription factor (SPDEF) gene promoter activity in human embryonic kidney 293 (HEK-293T) cells, a biomarker for mucin gene expression. Findings showed that moisture content and combustion condition significantly affected the organic and inorganic elemental composition of PM0.1 as well as its bioactivity. Also, for a given moisture and combustion scenario, PM chemistry and bioactivity differed considerably with PM size. Importantly, PM0.1 from flaming combustion of low-moisture pine contained the highest abundance of the oxygenated saturated aliphatic functional group [H-C-O] and was also biologically most potent in stimulating SPDEF promoter activity, suggesting the role of organic compounds such as carbohydrates and sugar alcohols (that contain [H-C-O]) in driving mucus-related respiratory outcomes. Our platform enables further well-controlled parametric studies using a combination of in vitro and in vivo approaches to link wood burning parameters with acute and chronic inhalation health effects of wood smoke.

Contribution of wood burning to exposures of PAHs and oxy-PAHs in Eastern Sweden

Abstract. A growing trend in developed countries is the use of wood as fuel for domestic heating due to measures taken to reduce the usage of fossil fuels. However, this imposed another issue with the environment and human health. That is, the emission from wood burning contributed to the increased level of atmospheric particulates and the wood smoke caused various respiratory diseases. The aim of this study was to investigate the impact of wood burning on the polycyclic aromatic hydrocarbons (PAHs) in air PM10 using known wood burning tracers, i.e. levoglucosan, mannosan and galactosan from the measurement at the urban background and residential areas in Sweden. A yearly measurement from three residential areas in Sweden showed a clear seasonal variation of PAHs during the cold season mainly from increased domestic heating and meteorology. Together, an increased sugar level assured the wood burning during the same period. The sugar ratio (levoglucosan/(mannosan+galactosan)) was a good marker for wood burning source such as the wood type used for domestic heating and garden waste burning. On the Walpurgis Night, the urban background measurement demonstrated a dramatic increase in levoglucosan, benzo[a]pyrene (B[a]P) and oxygenated PAHs (OPAHs) concentrations from the increased wood burning. A significant correlation between levoglucosan and OPAHs was observed suggesting OPAHs to be an indicator of wood burning together with levoglucosan. The levoglucosan tracer method and modelling used in predicting the B[a]P concentration could not fully explain the measured levels in the cold season. The model showed that the local wood source contributed to 98 % of B[a]P emissions in the Stockholm area and 2 % from the local traffic. However, non-local sources were dominating in the urban background (60 %). A further risk assessment estimated that the airborne particulate PAHs caused 13.4 cancer cases per 0.1 million inhabitants in Stockholm County.

Integrated genomics approaches identify transcriptional mediators and epigenetic responses to Afghan desert particulate matter in small airway epithelial cells.

Military Deployment to Southwest Asia and Afghanistan and exposure to toxic airborne particulates have been associated with an increased risk of developing respiratory disease, collectively termed deployment-related respiratory diseases (DRRDs). Our knowledge about how particulates mediate respiratory disease is limited, precluding the appropriate recognition or management. Central to this limitation is the lack of understanding of how exposures translate into dysregulated cell identity with dysregulated transcriptional programs. The small airway epithelium is involved in both the pathobiology of DRRD and fine particulate matter deposition. To characterize small airway epithelial cell epigenetic and transcriptional responses to Afghan desert particulate matter (APM) and investigate the functional interactions of transcription factors that mediate these responses, we applied two genomics assays, the assay for transposase accessible chromatin with sequencing (ATAC-seq) and Precision Run-on sequencing (PRO-seq). We identified activity changes in a series of transcriptional pathways as candidate regulators of susceptibility to subsequent insults, including signal-dependent pathways, such as loss of cytochrome P450 or P53/P63, and lineage-determining transcription factors, such as GRHL2 loss or TEAD3 activation. We further demonstrated that TEAD3 activation was unique to APM exposure despite similar inflammatory responses when compared with wood smoke particle exposure and that P53/P63 program loss was uniquely positioned at the intersection of signal-dependent and lineage-determining transcriptional programs. Our results establish the utility of an integrated genomics approach in characterizing responses to exposures and identifying genomic targets for the advanced investigation of the pathogenesis of DRRD.

The role of the peat seed bank in plant community dynamics of a fire‐prone New Zealand restiad bog

AbstractNew Zealand restiad bogs have histories of natural fire, which is reflected in the presence of plant species with adaptations such as serotiny and fire‐stimulated flowering. The possibility of fire‐cued germination has not been investigated in restiad bogs, despite its widespread occurrence in other fire‐prone environments, globally. We performed a glasshouse experiment to assess the role of peat seed banks in post‐fire regeneration at Kopuatai Bog in northern New Zealand. Peat samples collected were either (a) heated until they reached 70 °C, (b) exposed to wood smoke for 30 min, (c) heated and smoked consecutively, or (d) left untreated. The emergence of vascular plants was then monitored for 105 days in a glasshouse. Mean seedling density was highest in the control treatment (7228 ± SE 1040 m−2); it was lowest in the heated samples, suggesting that the heat treatment may have been excessive. Smoke did not significantly increase emergence. Epacris pauciflora accounted for 76.7% of total seedlings, consistent with our hypothesis based on vegetation surveys that this species relies on synchronous post‐fire seed bank germination. E. pauciflora was most abundant in the control, suggesting that emergence is in response to some disturbance‐related cue other than heat or smoke. The restiad Sporadanthus ferrugineus was abundant in the control and smoke treatments. Its emergence following heating was reduced, but still considerable enough to cast doubt on its classification as a fire‐sensitive species. In contrast, the dominant peat‐forming restiad Empodisma robustum showed low levels of emergence. Our overall findings demonstrate that substantial quantities of viable seed are stored in the upper peat layers of a restiad bog and are capable of germinating in response to disturbance‐related environmental changes. These findings contribute to our understanding of restiad peatland plant community dynamics, particularly explaining the mechanism behind increased E. pauciflora dominance post‐fire.

Lung Effects of Household Air Pollution

Biomass fuel smoke, secondhand smoke, and oxides of nitrogen are common causes of household air pollution (HAP). Almost 2.4 billion people worldwide use solid fuels for cooking and heating, mostly in low- and middle-income countries. Wood combustion for household heating is also common in many areas of high-income countries, and minorities are particularly vulnerable. HAP in low- and middle-income countries is associated with asthma, acute respiratory tract infections in adults and children, chronic obstructive pulmonary disease, lung cancer, tuberculosis, and respiratory mortality. Although wood smoke exposure levels in high-income countries are typically lower than in lower-income countries, it is similarly associated with accelerated lung function decline, higher prevalence of airflow obstruction and chronic bronchitis, and higher all-cause and respiratory cause-specific mortality. Household air cleaners with high-efficiency particle filters have mixed effects on asthma and chronic obstructive pulmonary disease outcomes. Biomass fuel interventions in low-income countries include adding chimneys to cookstoves, improving biomass fuel combustion stoves, and switching fuel to liquid petroleum gas. Still, the impact on health outcomes is inconsistent. In high-income countries, strategies for reducing biomass fuel-related HAP are centered on community-level woodstove changeout programs, although the results are again inconsistent. In addition, initiatives to encourage home smoking bans have mixed success in households with children. Environmental solutions to reduce HAP have varying success in reducing pollutants and health problems. Improved understanding of indoor air quality factors and actions that prevent degradation or improve pollutedindoor air may lead to enhanced environmental health policies, but health outcomes must be rigorously examined.

Physicochemical and toxicological properties of wood smoke particulate matter as a function of wood species and combustion condition

Wood burning is a major source of ambient particulate matter (PM) and has been epidemiologically linked to adverse pulmonary health effects, however the impact of fuel and burning conditions on PM properties has not been investigated systematically. Here, we employed our recently developed integrated methodology to characterize the physicochemical and biological properties of emitted PM as a function of three common hardwoods (oak, cherry, mesquite) and three representative combustion conditions (flaming, smoldering, incomplete). Differences in PM and off-gas emissions (aerosol number/mass concentrations; carbon monoxide; volatile organic compounds) as well as inorganic elemental composition and organic carbon functional content of PM0.1 were noted between wood types and combustion conditions, although the combustion scenario exerted a stronger influence on the emission profile. More importantly, flaming combustion PM0.1 from all hardwoods significantly stimulated the promoter activity of Sterile Alpha Motif (SAM) pointed domain containing ETS (E-twenty-six) Transcription Factor (SPDEF) in human embryonic kidney 293 (HEK-293 T) cells, a biomarker for mucin gene expression associated with mucus production in pulmonary diseases. However, no bioactivity was observed for smoldering and incomplete combustion, which was likely driven by differences in the organic composition of PM0.1. Detailed chemical speciation of organic components of wood smoke is warranted to identify the individual compounds that drive specific biological responses.