Multi-scale characterization of lead-rich deposited particles originating from the fire of Notre-Dame de Paris

Fire is a major hazard for built heritage. The fire at Notre-Dame on April 15, 2019 completely destroyed the woodframe and the lead roof (about 285 tons) almost entirely melted due to high temperatures. A part of the molten lead escaped into the atmosphere in the form of aerosols while the majority remains within cathedral enclosure in the form of deposits, metallic remains, spatters etc. In particular unusual yellowish deposits of lead-rich particles were observed and collected inside the monument (in the nave, near the organ and in St-Eloi Chapel). These were then thoroughly characterized to identify the neoformed lead compounds. Both bulk and local analyses were carried out to obtain particle morphology and size distribution, chemistry and mineralogy of the deposits, from macro to nanoscale. We found that the fire-related deposits all contain high amount of lead (10 to 44 %) mainly in the form of monoxides (litharge and massicot) with other lead-bearing phases (Ca-plumbate, metallic lead, lead sulfates and carbonates, plattnerite) in smaller amount. These lead phases are concentrated in heterogeneous microspheres, at the periphery of terrigenous minerals (calcite, quartz, feldspars) or mixed with anhydrite minerals. The size distribution shows that the fire produced giant particles (> 100 μm in diameter) similar to those found near the fallout from industrial emissions. This study provides a better understanding of the lead contamination pathways following the Notre-Dame cathedral fire and new insights into the reactivity of lead during a fire.

A novel causative factor of injury: Severe burns related to fires and explosions of lithium-ion batteries of electric motorcycles

Severe burns related to fires and explosions of lithium-ion batteries of electric motorcycles have not been reported to date. We retrospectively studied 419 patients admitted to our burn intensive care unit from January 2016 to December 2021. Of these 419 patients, 26 (22 male, 4 female; median age, 42 years) had burns related to lithium-ion battery fires and explosions, and all of their injury characteristics were similar to those of traditional flame burns. Lithium-ion battery-related burns were the eighth most common cause of burn injuries among all hospitalized patients. The 26 patients comprised 10 unemployed and 16 employed individuals. Twenty-three patients were injured at home during the battery charging process, and three were injured outdoors (one by a fire while the electric motorcycle was stationary and the others two by a fire while riding the motorcycle). The burn sites were distributed over the whole body; the burn area ranged from 10 % to 100 % of the total body surface area, and the burn depth ranged from superficial second-degree burns to third-degree burns. Twenty-three patients had inhalation injuries, and ten underwent prophylactic tracheostomy and intubation. Multiple operations were required for wound repair. Although convenient, lithium-ion electric motorcycles can also cause severe burns. To prevent these injuries, we must increase public safety awareness and education, develop new battery energy storage systems and battery management systems, and ensure the safety of batteries. Consumers should be aware of the potential dangers of lithium-ion batteries and comply with related security measures.

Technical note: Temperature estimation accuracy based on colourimetry of embalmed human and fresh non-human burned bone

Estimation of the exposure temperature of skeletal remains can be done by means of colourimetry and a previously published decision model for the colourimetric data, resulting in clusters that represent a range of exposure temperature. The method was based on thermally altered freshly burned human skeletal remains. However, in practice the origin or pre-burning condition of (possibly fragmentary) burned remains can be unknown. Further, in order to use the colourimetric analysis, and accompanying decision model, it is important to have a reference or test set. Fresh human material is not available for this purpose in all countries. Hence, the classification accuracy of the decision model was tested for, in some countries more readily available substitutes for fresh bone; embalmed human bone and non-human bone. The model yielded high accuracies for these sample materials, making it possible to create a reference or test set from fresh non-human and embalmed human bone as substitute for human, and also to use the decision model for these deviating samples in practice.

Evaluating building stones: Physical-mechanical changes from high-temperature fire and water cooling

Heritage sites built with natural stone are at risk from fires, which can alter stone properties and compromise its structural integrity. Over 60 studies in the past three decades have examined fire impact on natural stone, providing insights for their prevention and restoration. The primary objectives are to develop effective strategies to mitigate fire risks, protect heritage structures, and ensure the preservation of our cultural legacy. Two noteworthy Portuguese limestones used as heritage building materials: Lioz (LL) and grey Ançã stone (GAS), were studied regarding the effect of high-temperature exposure for simulating fire at 200 °C, 400 °C and 600 °C, followed by cooling in water to reproduce fire extinguish in natural stone buildings. The findings provided insights into how the different temperatures impact the stone morphological, physical and mechanical properties. Color measurements (CIE L*a*b*) showed a color difference from 3 to 32 %; SEM-EDS confirmed microstructure modifications after fire exposure with cracks formation and intragranular porosity development. Among the diverse physical and mechanical properties of the stones, uniaxial compressive strength decreased from 1 to 33 %, Leeb D hardness decreased up to 12.2 %, lowering in open porosity was detected in the range 70-289 % and ultrasound speed propagation were significantly affected after thermal cycle at 600 °C with a negative variation reaching 49 %. Results from TGA show a loss of mass due to retained water (∼40 °C) and loss of hydration water at ∼ 120 °C in both limestones. The total mass loss (∼42-∼44 %) is associated with the loss of H2O, CO2. In conclusion, stones with higher toughness and compression strength exhibited reduced damage at high temperatures due to their enhanced resistance to fracturing under stress. As limestone's mechanical strength decreases under high temperatures, it's advisable to increase its thickness to ensure sufficient support for loads and intended conditions of use. The deficiency of analysis on limestone's mechanical decay from fire reveals a significant knowledge gap regarding the complete extent of damage and deterioration in stone heritage structures.

Pyric herbivory decreases soil denitrification despite increased nitrate availability in a temperate grassland

Pyric herbivory, the combination of controlled burning and targeted grazing, is an effective strategy for restoring abandoned, shrub-encroached rangelands to open ecosystems. This practice may impact soil nitrogen pools by altering soil nitrification and denitrification rates, and may lead to an increase of nitrogen losses through nitrate leaching and N-gas emissions. This research, located in the south-western Pyrenees, investigated the effects of pyric herbivory on soil nitrification and denitrification potentials and mineral nitrogen content in a gorse-encroached temperate rangeland six months after the burning was implemented. The study included three treatments: high-severity burning plus grazing, low-severity burning plus grazing, and unburned and ungrazed areas (control). We measured soil nitrification and denitrification potentials (net and gross), the limitation of denitrifiers by nitrogen or organic carbon, and the abundance of nitrite- and nitrous oxide-reducing bacteria. Additional soil and vegetation data complemented these measurements. Results showed that pyric herbivory did not significantly affect nitrification potential, which was low and highly variable. However, it decreased gross denitrification potential and nitrous oxide reduction to dinitrogen in high-severely burned areas compared to the control. Denitrification rates directly correlated with microbial biomass nitrogen, soil organic carbon, soil water content and abundance of nirS-harbouring bacteria. Contrary to the expected, soil nitrate availability did not directly influence denitrification despite being highest in burned areas. Overall, the study suggests that pyric herbivory does not significantly affect mid-term nitrification rates in temperate open ecosystems, but may decrease denitrification rates in intensely burned areas. These findings highlight the importance of assessing the potential impacts of land management practices, such as pyric herbivory, on soil nutrient cycling and ecosystem functioning.

Fire effects on soil CH4 and N2O fluxes across terrestrial ecosystems

Fire, as a natural disturbance, significantly shapes and influences the functions and services of terrestrial ecosystems via biotic and abiotic processes. Comprehending the influence of fire on soil greenhouse gas dynamics is crucial for understanding the feedback mechanisms between fire disturbances and climate change. Despite work on CO2 fluxes, there is a large uncertainty as to whether and how soil CH4 and N2O fluxes change in response to fire disturbance in terrestrial ecosystems. To narrow this knowledge gap, we performed a meta-analysis synthesizing 3615 paired observations from 116 global studies. Our findings revealed that fire increased global soil CH4 uptake in uplands by 23.2 %, soil CH4 emissions from peatlands by 74.7 %, and soil N2O emissions in terrestrial ecosystems (including upland and peatland) by 18.8 %. Fire increased soil CH4 uptake in boreal, temperate, and subtropical forests by 20.1 %, 38.8 %, and 30.2 %, respectively, and soil CH4 emissions in tropical forests by 193.3 %. Additionally, fire negatively affected soil total carbon (TC; -10.3 %), soil organic carbon (SOC; -15.6 %), microbial biomass carbon (MBC; -44.8 %), dissolved organic carbon (DOC; -27 %), microbial biomass nitrogen (MBN; -24.7 %), soil water content (SWC; -9.2 %), and water table depth (WTD; -68.2 %). Conversely, the fire increased soil bulk density (BD; +10.8 %), ammonium nitrogen (NH4+-N; +46 %), nitrate nitrogen (NO3--N; +54 %), pH (+4.4 %), and soil temperature (+15.4 %). Our meta-regression analysis showed that the positive effects of fire on soil CH4 and N2O emissions were significantly positively correlated with mean annual temperature (MAT) and mean annual precipitation (MAP), indicating that climate warming will amplify the positive effects of fire disturbance on soil CH4 and N2O emissions. Taken together, since higher future temperatures are likely to prolong the fire season and increase the potential of fires, this could lead to positive feedback between warming, fire events, CH4 and N2O emissions, and future climate change.

Polycyclic aromatic compounds in a northern freshwater ecosystem: Patterns, sources, and the influences of environmental factors

Polycyclic aromatic compounds (PACs) - a large group of organic chemicals naturally present in petroleum deposits (i.e., petrogenic) or released into the environment by incomplete combustion of organic materials (i.e., pyrogenic) - represent a potential risk to the health of aquatic ecosystems. In high latitude freshwater ecosystems, concentrations of PACs may be increasing, yet there are limited studies in such systems to assess change and to understand threats. Using 10 years of contemporary data from passive samplers deployed across five regions (n = 43 sites) in the Mackenzie River Basin, we (i) describe baseline levels of PACs, (ii) assess spatiotemporal patterns, and (iii) evaluate the extent to which environmental factors (fire, snowmelt, and proximity to oil infrastructure) influence concentrations in this system. Measured concentrations were low, relative to those in more southern systems, with mixtures primarily being dominated by non-alkylated, low molecular weight compounds. Concentrations were spatially consistent, except for two sites near Norman Wells (an area of active oil extraction) with increased levels. Similarly, observed annual variation was minimal, with 2014 having generally higher levels of PACs. We did not detect effects of fire, snowmelt, or oil infrastructure on concentrations. Taken together, our findings suggest that PACs in the Mackenzie River are currently at low levels and are primarily petrogenic in origin. They further indicate that ongoing monitoring and testing of environmental drivers (especially at finer spatial scales) are needed to better predict how ecosystem change will influence PAC levels in the basin and in other northern systems.

How will climate change and forest harvesting influence the habitat quality of two culturally salient species?

Boreal landscapes face increasing disturbances which can affect cultural keystone species, i.e. culturally salient species that shape in a major way the cultural identity of a people. Given their importance, the fate of such species should be assessed to be able to act to ensure their perennity. We assessed how climate change and forest harvesting will affect the habitat quality of Rhododendron groenlandicum and Vaccinium angustifolium, two cultural keystone species for many Indigenous peoples in eastern Canada. We used the forest landscape model LANDIS-II in combination with species distribution models to simulate the habitat quality of these two species on the territories of three Indigenous communities according to different climate change and forest harvesting scenarios. Climate-sensitive parameters included wildfire regimes as well as tree growth. Moderate climate change scenarios were associated with an increased proportion of R. groenlandicum and V. angustifolium in the landscape, the latter species also responding positively to severe climate change scenarios. Harvesting had a minimal effect, but slightly decreased the probability of presence of both species where it occurred. According to the modeling results, neither species is at risk under moderate climate change scenarios. However, under severe climate change, R. groenlandicum could decline as the proportion of deciduous trees would increase in the landscape. Climate change mitigation strategies, such as prescribed fires, may be necessary to limit this increase. This would prevent the decrease of R. groenlandicum, as well as contribute to preserve biodiversity and harvestable volumes.

Fire deaths in Cape Town, South Africa: A retrospective review of medico-legal and toxicological findings (2006 - 2018)

BACKGROUND

In South Africa, fire-related deaths are common, particularly within dense informal housing settlements. Published data on deaths from fire incidents in Cape Town is sparse. Additionally, little emphasis has been placed on the role of toxicological investigations in these deaths, despite the known risk of alcohol and drug impairment to burn injury.

METHODS

A retrospective, descriptive analysis of post-mortem case reports from Salt River Mortuary was conducted to investigate all deaths in which fires were involved in the west metropole of Cape Town, between 2006 to 2018. Demographic, circumstantial, and toxicological data were analyzed using R software.

RESULTS

In total 1370 fire deaths occurred over 13 years, with a mean of 106 (SD ± 18) cases per annum (≈3% of the annual caseload and a mortality rate of 5.5 per 100,000). Males (70.4%), adults (mean=30.7 years), and toddlers (1-4 years old) were notably at risk. Deaths typically occurred in the early morning (00h00 - 06h00) (45.7%), during winter (32.1%), and in lower socioeconomic areas with highly dense informal settlements (65.6%), with 29% of deaths occurring in multi-fatality incidents. Ethanol was detected (≥0.01 g/100 mL) in 55.1% of cases submitted for analysis (71.5%), with a mean of 0.18 g/100 mL, and with 93.8% of positive cases > 0.05 g/100 mL. Carboxyhaemoglobin (COHb) analysis was requested in 76.4% of cases, with 57% of cases having a %COHb of ≥ 20%. Toxicology results (for drugs other than ethanol) from the national laboratory were outstanding in 34.4% of the cases at the conclusion of the study. BAC and %COHb were significantly higher in deaths from burns and smoke inhalation (usually accidents) than deaths from combined trauma and burns (typically homicides). Fire deaths with high COHb levels were more likely to display cherry-red discoloration (OR=3.1) and soot in the airways (OR=2.7) at autopsy.

CONCLUSION

This article provides an updated description of fire deaths in the west metropole of Cape Town. The importance of BAC and COHb testing in these cases was noted, and the authors call for an investigation of the role of drug impairment (specifically frequently misused drugs methamphetamine and methaqualone) as a risk factor in these deaths. Areas of high-density informal settlements, where open flames are used to heat, light, and cook, were noted as high risk.

Siting of fuel stations within residential areas in Ghanaian cities: Perceptions of residents in Wa on fire disaster risks

This paper responds to the limited literature on perceptions of fire disaster risks associated with the siting of fuel stations in dense residential areas in African cities. We address three interrelated research objectives regarding fire disaster risk and safety behaviours. First, we explore residents' perception of the reasons for the siting of fuel stations in residential areas. Second, we examine their sociodemographic characteristics and perception of fire disaster risks associated with fuel stations; and third, we examine residents' fire safety behaviours around fuel stations. We address these objectives by engaging with risk perception theory and protection motivation theory as well as an empirical review of literature worldwide. We also draw evidence from Wa in Ghana using a mixed research approach involving 182 participants. Through a questionnaire, observation checklist, a camera, and an in-depth interview guide, we elicited data from residents and relevant stakeholders to address our research questions. The quantitative data were analysed using descriptive statistics and a chi-square test, while thematic analysis was used to analyse the responses obtained from the interviews. We found that ease of access and competition motivated the siting of fuel stations in residential areas. Although residents knew the risk of living near fuel stations, measures were not implemented to reduce their vulnerability to fire disasters. People living near fuel stations should be encouraged to invest in equipment and take measures to reduce their vulnerability to fire disasters.

Experimental study to compare the strength of concrete with different amounts of polypropylene fibers at high temperatures

It is widely known that adding fibers to concrete improves the properties of concrete, which has a brittle behavior. Although concrete has high compressive strength but poor tensile strength, this has led researchers to offer a variety of ways to deal with this weakness. The use of fibers is one of the methods used to enhance concrete behavior. Fire is one of the most important cases in structures; if the temperature is high or its duration is long, it will cause serious damage to the structure. The present study is an experimental study in which different concrete samples with different amounts of polypropylene fibers and different cement content are exposed once at a normal temperature of 25 °C and again at high temperatures, including 250 °C and 500 °C. The effect of temperature on the compressive and tensile strengths of concrete containing 0.5%, 1.5%, and 2% polypropylene fibres and with cement contents of 200 kg/m3, 260 kg/m3, and 320 kg/m3. The compressive and tensile strength was evaluated at curing 28 days of strength. The results showed a severe strength loss for all concretes after exposure to 500 °C. The relative compressive strengths of concretes containing PP fibers were higher than those of concretes without PP fibers. The tensile strength of concrete was more sensitive to high temperatures than the compressive strength. Based on the test results, it can be concluded that adding 2% PP fibers can significantly promote the residual mechanical properties of concrete during heating. The compressive strength at 25 °C with 2% PP fibres decreases by 43% with cement contents of 200 kg/m3 and 64% with cement contents of 260 kg/m3, and 37% with cement contents of 320 kg/m3, respectively. Also, the compressive strength at 500 °C with 2% PP fibres decreases by 61% with 200 kg/m3, 59% with 260 kg/m3, and 42% with cement contents of 320 kg/m3, respectively.

Pregnancy exposure to PM2.5 from wildland fire smoke and preterm birth in California

BACKGROUND

Wildfires in the Western United States are a growing and significant source of air pollution that is eroding decades of progress in air pollution reduction. The effects on preterm birth during critical periods of pregnancy are unknown.

METHODS

We assessed associations between prenatal exposure to wildland fire smoke and risk of preterm birth (gestational age < 37 weeks). We assigned smoke exposure to geocoded residence at birth for all live singleton births in California conceived 2007-2018, using weekly average concentrations of particulate matter ≤ 2.5 µm (PM2.5) attributable to wildland fires from United States Environmental Protection Agency's Community Multiscale Air Quality Model. Logistic regression yielded odds ratio (OR) for preterm birth in relation to increases in average exposure across the whole pregnancy, each trimester, and each week of pregnancy. Models adjusted for season, age, education, race/ethnicity, medical insurance, and smoking of the birthing parent.

RESULTS

For the 5,155,026 births, higher wildland fire PM2.5 exposure averaged across pregnancy, or any trimester, was associated with higher odds of preterm birth. The OR for an increase of 1 µg/m3 of average wildland fire PM2.5 during pregnancy was 1.013 (95 % CI:1.008,1.017). Wildland fire PM2.5 during most weeks of pregnancy was associated with higher odds. Strongest estimates were observed in weeks in the second and third trimesters. A 10 µg/m3 increase in average wildland fire PM2·5 in gestational week 23 was associated with OR = 1.034; 95 % CI: 1.019, 1.049 for preterm birth.

CONCLUSIONS

Preterm birth is sensitive to wildland fire PM2.5; therefore, we must reduce exposure during pregnancy.

A European-scale analysis reveals the complex roles of anthropogenic and climatic factors in driving the initiation of large wildfires

Analysing wildfire initiation patterns and identifying their primary drivers is essential for the development of more efficient fire prevention strategies. However, such analyses have traditionally been conducted at local or national scales, hindering cross-border comparisons and the formulation of broad-scale policy initiatives. In this study, we present an analysis of the spatial variability of wildfire initiations across Europe, focusing specifically on moderate to large fires (> 100 ha), and examining the influence of both human and climatic factors on initiation areas. We estimated drivers of fire initiation using machine learning algorithms, specifically Random Forest (RF), covering the majority of the European territory (referred to as the "ET scale"). The models were trained using data on fire initiations extracted from a satellite burned area product, comprising fires occurring from 2001 to 2019. We developed six RF models: three considering all fires larger than 100 ha, and three focused solely on the largest events (> 1000 ha). Models were developed using climatic and human predictors separately, as well as both types of predictors mixed together. We found that both climatic and mixed models demonstrated moderate predictive capacity, with AUC values ranging from 79 % to 81 %; while models based only on human variables have had poor predictive capacity (AUC of 60 %). Feature importance analysis, using Shapley Additive Explanations (SHAP), allowed us to assess the primary drivers of wildfire initiations across the European Territory. Aridity and evapotranspiration had the strongest effect on fire initiation. Among human variables, population density and aging had considerable effects on fire initiation, the former with a strong effect in mixed models estimating large fires, while the latter had a more important role in the prediction of very large fires. Distance to roads and forest-agriculture interfaces were also relevant in some initiation models. A better understanding of drivers of main fire events should help designing European forest fire management strategies, particularly in the light of growing importance of climate change, as it would affect both fire severity and areas at risk. Factors of fire initiation should also be part of a comprehensive approach for fire risk assessment, reduction and adaption, contributing to more effective wildfire management and mitigation across the continent.

An uncut copy of Scleromyceti Sueciae: lost and then found

BACKGROUND

A copy of Scleromyceti Sueciae, a work on which the nomenclature of many fungi is based was known to occur in Scotland's Glasgow University Botany Department but the buildings were devastated by fire in 2001 and the whereabouts of this important work, if it existed, was lost. Its re-finding is reported herein.

RESULTS

The Glasgow copy of Scleromyceti Sueciae, an uncut first edition of Fries' work, was located in the Glasgow Museums in its original cabinet being transferred there years before the fire and its specimens being now databased. It is one of the few existing uncut copies of this important scientific work and one of the best-preserved copies of the first edition.

CONCLUSION

The discovery of this first edition of Scleromyceti Sueciae emphasizes the significance to reserve special conservation for important collections by early mycologists. It also allows interested mycologists world-wide to know of the existence in Glasgow of an uncut, first edition copy.

The utility of blow fly (Diptera: Calliphoridae) evidence from burned human remains

Burning of human remains is a common method to conceal or destroy evidence associated with homicides and illegal activities. However, data regarding blow fly colonization of burned remains are scarce, with all previously published empirical studies focusing only on non-human animals. It is critically important to obtain basic data on blow fly colonization patterns of burned human remains as such evidence may represent the only feasible method for PMI estimation in cases of burning. In this study, we thermally altered six human donors to a Crow-Glassman Scale Level 3 (CGS-3) and placed them at the Anthropology Research Facility at the University of Tennessee in Summer 2021, Spring 2022, and Summer 2022. Six unburned human donors were used as controls. Observations for insect activity began within 24 h of placement and continued twice weekly through decomposition. Age estimations were performed with immature blow flies to estimate the time of colonization (TOC), and accuracy was assessed against the time of placement for each donor. All burned donors examined in this study were colonized by blow flies. No significant difference in species composition was determined between treatments, though TOC estimations from burned donors were slightly (but significantly) less accurate than TOC estimations from unburned donors (80% vs. 83% accuracy; χ2 = 0.041, df = 1, P = 0.840). These results indicate that blow flies can successfully colonize human remains burned to CGS-3 and that accurate TOC estimations can still be generated from larval specimens. Though several limitations to this study exist (e.g., inconsistent donor BMI, lack of donor temperature data), our results underscore the utility of entomological evidence in cases of burned human remains.

Exposure Assessment Study on Lithium-Ion Battery Fire in Explosion Test Room in Battery Testing Facility

A lithium-ion battery is a rechargeable battery that uses the reversible reduction of lithium ions to store energy and is the predominant battery type in many industrial and consumer electronics. The lithium-ion batteries are essential to ensure they operate safely. We conducted an exposure assessment five days after a fire in a battery-testing facility. We assessed some of the potentially hazardous materials after a lithium-ion battery fire. We sampled total suspended particles, hydrogen fluoride, and lithium with real-time monitoring of particulate matter (PM) 1, 2.5, and 10 micrometers (μm). The area sampling results indicated that primary potential hazardous materials such as dust, hydrogen fluoride, and lithium were below the recommended limits suggested by the Korean Ministry of Labor and the American Conference of Governmental Industrial Hygienists Threshold Limit Values. Based on our assessment, workers were allowed to return to work.

Research on the evacuation of people from a road tunnel fire based on a mathematical model

A mathematical model for the evacuation of people from a road tunnel is created, taking into account various factors such as the speed at which people move, the density of the flow of people, and the outcome of the fire. This model allows for the precise calculation of the evacuation time and the optimization of the evacuation route in a fire scenario. The constructed mathematical model was used to determine how long it would take for people to evacuate this road tunnel, and the findings of the Pathfinder simulation were compared. The findings demonstrate a relationship between the model's evacuation time and the human flow density, movement velocity, and fire product characteristics. The evacuation time is closer to the outcome of the actual fire scene when the impact of the fire environment on the speed of evacuation is quantified. The mathematical model of human evacuation's calculation of the evacuation time is essentially accurate when compared to the Pathfinder simulation's calculation, with an error of only 0.77 %. The model provides recommendations for optimizing the evacuation of people from a road tunnel in the case of a fire by not only predicting where the crowding would occur but also by calculating the duration of the crowding.

Using high-resolution land cover data to assess structure loss in the 2018 Woolsey Fire in Southern California

There are growing concerns about increases in the size, frequency, and destructiveness of wildfire events. One commonly used mitigation strategy is the creation and maintenance of defensible space, a zone around buildings where vegetation is managed to increase potential for structures to survive during wildfires. Despite widespread acceptance and advocacy of defensible space, few studies provide empirical evidence documenting the efficacy of different fuel modification practices under real wildfire conditions. The 2018 Woolsey Fire in Los Angeles County, California, occurred a short time after high-resolution (0.07 m2) land cover data were created, providing a unique opportunity to quantify vegetation before the fire. We integrated measurements from this high-resolution land cover data with parcel data, building attributes, and environmental context. We then used Random Forests models to analyze the extent to which these factors predicted structure loss in the wildfire. Variable importance scores showed vegetation around buildings was not a strong predictor of building-level damage outcomes compared to building materials and landscape features such as paved land cover per parcel, elevation, building density, and distance to road networks. Among building materials, multi-paned windows and enclosed eaves were most highly associated with building survival. These results are consistent with other studies that conclude building materials and environmental context are more related to survivorship than defensible space.

Wildfire and cattle legacies on gradients of soil nitrogen underlie patterns of annual brome invasion

Human activities are increasing wildfires and livestock activity in arid ecosystems with potential implications for the spread of invasive grasses. The objective of this study was to test whether fire history and cattle activity alter soil resource gradients, thereby affecting patterns of Bromus rubens L. (red brome) invasion. Six paired burned and unburned transect lines (1-km long) were established in the northeast Mojave Desert along the boundaries of four independent wildfire scars. At 100-m transect increment points, we measured the distance to the two nearest cowpats, and two random points and measured the density, height, biomass, and seed production of red brome, soil moisture and inorganic nitrogen (N). Cattle activity was 29% greater along burned transects compared to unburned transects (P < 0.05). Red brome height, density, and seed production were 11-34% greater along burned transects than unburned transects (P < 0.05). Red brome height, biomass, density, and seed production were twofold to tenfold greater next to cowpats compared to random points (P < 0.05). Soils along burned transects and beneath cowpats had greater soil inorganic N (P < 0.05), which was positively correlated with red brome density, height, biomass, and seed production (R2 = 0.60-0.85, P < 0.0001). Transgenerational effects were evident as seeds from red brome next to cowpats had 27% higher germination than seeds collected from random points. Positive responses of red brome to increased inorganic N related to fire and cattle activity may contribute fine fuel infill that drives invasive grass-fire cycles in deserts.

Spatio-temporal assessment of soil properties immediately and eight months after a high intensity-controlled burn in the south of Spain

In recent years, the use of fire as a means by which to manage forest ecosystems has become more frequent in Europe. Fire has a significant impact on the soil, and it is therefore necessary to understand how controlled burns affect this invaluable resource. The purpose of this study was to evaluate the main alterations in the physical-chemical and biological properties of the soil because of a high intensity-controlled burn in "Los Boquerones" area (Villaviciosa de Córdoba, Spain). Additionally, we assessed the spatial heterogeneity of the alterations of different soil properties. A grid of 12 points was established on a hillside in Sierra Morena (Córdoba). Thermocouples were placed at each point, and soil samples were collected at two depths (0-2 cm and 2-5 cm) before burning, immediately after burning and eight months later. Soil pH, electrical conductivity, nutrient content and/or availability, among others, and their spatio-temporal variations were analysed. Soil pH, increased in the first centimetres of the soil (0-2 cm) immediately after burning up to >2 units, and the increase was maintained eight months following the burn. Additionally, the high-intensity burn had a positive short-term effect on some of the soil properties, such as nutrient availability for plants, which was considerably increased. The magnitude of the alterations in the soil indicators assessed was spatially explained by the behaviour of the fire during the controlled burning. The burn also had both direct and indirect effects on soil microorganisms. In conclusion, the possible immediate and short-term effects of burning on the soil resource should be considered for a more holistic management of fire in forest ecosystems, as its functionality and capacity to provide ecosystem services is largely altered by these events as a function of their intensity.

Surface coated ZnO powder as flame retardant for wood: A short communication

In the present study, the ability of a coating of zinc oxide (ZnO) powder to improve the fire-safety of wood exposed to radiative heat flux was examined, focusing on the ignition time of the wood. To test ZnO's efficiency on the wood substrate, two different amounts of ZnO (0.5 and 1 g ZnO per dm2) were applied to the wood surface and exposed to radiative heat from a cone calorimeter wherein a pristine piece of wood with no ZnO treatment was taken as control. The experiments were conducted at three different irradiation levels i.e., 20, 35, and 50 kWm-2. The results showed that applying ZnO on the surface of the wood significantly increased the ignition time (TTI). For the three different heat fluxes, using 0.5 g ZnO per dm2 coating on the wood surface increased the TTI by 26-33 %. Furthermore, the application of 1 g of ZnO per dm2 generated a TTI increment of 37-40 %. All three irradiation levels showed similar trends in TTI. The micrographs taken before and after combustion showed no significant disparity in the morphology of ZnO. The agglomerated ZnO particles on the wood surface remained intact after combustion. This study demonstrates a facile method of using ZnO to delay the ignition of wood. This could potentially impart fire-safety to wooden structures/façades in wildland-urban interfaces and elsewhere by reducing flame spread.

Managing high-risk behaviours and challenges to prevent housing loss in permanent supportive housing: a rapid review

Permanent supportive housing is an effective intervention for stably housing most people experiencing homelessness and mental illness who have complex support needs. However, high-risk behaviours and challenges are prevalent among this population and have the potential to seriously harm health and threaten housing tenures. Yet, the research on the relationship between high-risk issues and housing stability in permanent supportive housing has not been previously synthesized. This rapid review aimed to identify the housing-related outcomes of high-risk behaviours and challenges in permanent supportive housing settings, as well as the approaches used by agencies and residents to address them. A range of high-risk behaviours and challenges were examined, including risks to self (overdose, suicide/suicide attempts, non-suicidal self-injury, falls/fall-related injuries), and risks to multiple parties and/or building (fire-setting/arson, hoarding, apartment takeovers, physical/sexual violence, property damage, drug selling, sex trafficking). The search strategy included four components to identify relevant academic and grey literature: (1) searches of MEDLINE, APA PsycINFO, and CINAHL Plus; (2) hand searches of three journals with aims specific to housing and homelessness; (3) website browsing/searching of seven homelessness, supportive housing, and mental health agencies and networks; and (4) Advanced Google searches. A total of 32 articles were eligible and included in the review. Six studies examined the impacts of high-risk behaviours and challenges on housing tenancies, with overdose being identified as a notable cause of death. Twenty-six studies examined approaches and barriers to managing high-risk behaviours and challenges in PSH programs. These were categorized into eight types of approaches: (1) clinical, (2) relational/educational, (3) surveillant, (4) restrictive, (5) strategic, (6) design-based, (7) legal, and (8) self-defence. Consistent across all approaches was a lack of rigorous examination of their effectiveness. Further, some approaches that are legal, restrictive, surveillant, or strategic in nature may be used to promote safety, but may conflict with other program objectives, including housing stability, or resident empowerment and choice. Research priorities were identified to address the key evidence gaps and move toward best practices for preventing and managing high-risk behaviours and challenges in permanent supportive housing.

Characterization of global fire activity and its spatiotemporal patterns for different land cover types from 2001 to 2020

Fire is a widespread phenomenon that plays an important role in Earth's ecosystems. This study investigated the global spatiotemporal patterns of burned areas, daytime and nighttime fire counts, and fire radiative power (FRP) from 2001 to 2020. The month with the largest burned area, daytime fire count, and FRP presented a bimodal distribution worldwide, with dual peaks in early spring (April) and summer (July and August), while the month with the largest nighttime fire count and FRP showed a unimodal distribution, with a peak in July. Although the burned area showed decline at the global scale, a significant increase occurred in temperate and boreal forest regions, where nighttime fire occurrence and intensity have consistently increased in recent years. The relationships among burned area, fire count, and FRP were further quantified in 12 typical fire-prone regions. The burned area and fire count exhibited a humped relationship with FRP in most tropical regions, whereas the burned area and fire count constantly increased when the FRP was below approximately 220 MW in temperate and boreal forest regions. Meanwhile, the burned area and FRP generally increased with the fire count in most fire-prone regions, indicating an increased risk of more intense and larger fires as the fire count increased. The spatiotemporal dynamics of burned areas for different land cover types were also explored in this study. The results suggest that the burned areas in forest, grassland, and cropland showed dual peaks in April and from July to September while the burned areas in shrubland, bareland, and wetlands usually peaked in July or August. Significant increases in forest burned area were observed in temperate and boreal forest regions, especially in the western U.S. and Siberia, whereas significant increases in cropland burned area were found in India and northeastern China.

In vitro effect of burned pasture soil on eggs and free-living larvae of ruminant gastrointestinal nematodes

Gastrointestinal nematodes are the most expensive agent of disease currently facing the livestock production industry. Spending the beginning of their life cycle as eggs and free-living larvae, nematodes are vulnerable to a multitude of external environmental factors. Fire is a naturally occurring force of nature that has both destructive and reconstructive effects on soil characteristics which nematode stages rely on for survival. The aim of this project was to evaluate in vitro the effect of burned pasture soil (200 °C and 500 °C) on the free-living stages of ruminant nematodes. We tested the effect of burned soil on the ability of eggs to hatch and produce infective larvae, and then tested survival of infective larvae within burned soil. Adding burned soil (500 °C) to larval cultures improved larval yield compared to larval cultures containing raw soil or soil burned at a lower heat (200 °C), and raw soil improved longer term survival of infective larvae. We were able to recover significantly more larvae from samples with low soil content either as raw or soil burned at 200 °C, when compared with samples with soil burned at 500 °C. This study has shown that the survival of gastrointestinal nematodes at the L3 stage is negatively impacted by the addition of soil burned at 500 °C. Although this temperature is closest to that of a medium intensity wildfire, which is a typically destructive process in agriculture, it reduces the number of infective GIN larvae available for animals to ingest. These experiments enable us to address in vitro if post-fire soil conditions alter the number of infective larvae available on pasture, and thus the infectivity of the pasture to livestock.

Optode-based chemical imaging of laboratory burned soil reveals millimeter-scale heterogeneous biogeochemical responses

Soil spatial responses to fire are unclear. Using optical chemical sensing with planar 'optodes', pH and dissolved O₂ concentration were tracked spatially with a resolution of 360 μm per pixel for 72 h after burning soil in the laboratory with a butane torch (∼1300 °C) and then sprinkling water to simulate a postfire moisture event. Imaging data from planar optodes correlated with microbial activity (quantified via RNA transcripts). Post-fire and post-wetting, soil pH increased throughout the entire ∼13 cm × 17 cm × 20 cm rectangular cuboid of sandy loam soil. Dissolved O₂ concentrations were not impacted until the application of water postfire. pH and dissolved O₂ both negatively correlated (p < 0.05) with relative transcript expression for galactose metabolism, the degradation of aromatic compounds, sulfur metabolism, and narH. Additionally, dissolved O₂ negatively correlated (p < 0.05) with the relative activity of carbon fixation pathways in Bacteria and Archaea, amoA/amoB, narG, nirK, and nosZ. nifH was not detected in any samples. Only amoB and amoC correlated with depth in soil (p < 0.05). Results demonstrate that postfire soils are spatially complex on a mm scale and that using optode-based chemical imaging as a chemical navigator for RNA transcript sampling is effective.