Nearby Fires Research Articles

Temperature dependence of emission of volatile organic compounds (VOC) from litters collected in two Mediterranean ecosystems determined before the flaming phase of biomass burning

Fire represents a major threat to Mediterranean terrestrial ecosystems because of the high temperatures reached during summer. While massive loads of organic, inorganic compounds and particulate matter are known to be emitted into the atmosphere from forest wildfires, less is known about the emission from vegetation surrounding fires where air temperatures higher than 100 °C can be reached. Little information exists on the emission from dead vegetation accumulated as litter over forest soils, from which fires often starts. In this study, the response of litter to heatwaves generated by nearby fires was investigated under controlled conditions. Litter samples collected in a Mediterranean maquis and a Holm oak stand during summer were placed in an enclosure flushed with a continuous flow of air, the temperature of the enclosure was progressively risen to 125 °C, until some smog developed but no flaming occurred. The gas from the enclosure was analysed for the content of CO2, H2O, and volatile organic compounds (VOC) to assess the dependence of emission from the air temperature. VOC emission was continuously determined by Proton-Transfer-Reaction mass spectrometry with time of flight (PTR-TOF-MS). Data obtained were complemented with those obtained by collecting VOC on traps that were later analysed by Gas chromatography–mass spectrometry (GC-MS). Results provided useful information to understand the emission mechanism of VOC and other gases from dead vegetation present in the litter of two Mediterranean ecosystems, both dominated by evergreen vegetation species. The study demonstrated that low molecular weight VOC and aromatic hydrocarbons (arenes) produced mostly by thermal oxidation of the wood biopolymers are emitted in addition to isoprenoids typically associated to storage organs and photosynthetic pathway. Moreover, our results support parameterization of litter VOC emission processes in air quality models.

Carbon monoxide profile variability over the Manaus Metropolitan Region and its relations with biomass burning

The present study analyzes the temporal variability of carbon monoxide (CO) over the Manaus Metropolitan Region (MMR) and its relations with nearby fires based on data obtained by the environmental satellite AQUA, for the 2003–2020 period. For this purpose, wavelet transform analyses and wavelet coherence analyses were used. The results show a well-defined seasonal behavior, with an increase and decrease in mean CO concentrations during dry and wet seasons, respectively. Semiannual and annual scales represent around 95 % of CO temporal variability in lower troposphere (500 to 1,000 hPa) and are associated with rains and fires dynamics in the region. In terms of interannual variability, multiple variability scales (1.2–2, 2.5–3 and 4.5–6 years) were observed, which explain around 10–15 % of concentration variability near surface. The results suggest that climatic variations, associated with the tropical Pacific and Atlantic sea surface temperature variations, on these different time scales, affect rain dynamics and, consequently, fires and CO concentration. Specifically, in 2015/16, the combined effect from different variability scales acted to prolong the dry period over the region, which contributed to increase fires and the CO to reach higher values compared to previous years. These results show a new aspect of the importance of evaluating the combined effect of different climate variability scales on CO concentrations in the atmosphere.

Smart Fire Fighting Robot

Ever since the Industrial revolution, more and more factories and industries are being set up around the world. Be it manufacturing or iron-steel industry. There are many places in factories, industries, manufacturing plants, oil fields, etc. where there is a risk of fire but they are unmanned. There may be fires in remote places like, in small gaps or in narrow pipes where humans can’t reach. The solution to these problems is our smart firefighting robot which can be controlled via mobile, and can even detect nearby fires and extinguish them. We aim to create a small smart firefighting robot that can be remotely controlled as well as act on its own by detecting nearby fire and extinguish it using on board water supply. The robot will use Arduino as well as NodeMCU so that it can be connected to Wi-Fi and controlled. The robot will also sound the buzzer whenever it detects fire, so that even if the fire can’t be extinguished, people nearby can be alerted.

Nearby wildfire impacts, social vulnerability, and birthweight in a rural population

BACKGROUND AND AIM Wildfires are increasing across the world and are associated with adverse impacts on vulnerable populations including pregnant people and young children. Wildfires may exert their harmful effects by elevating air pollutant exposure and may also fuel stress by disrupting daily activities and, if extreme, threatening or forcing evacuation. We aimed to estimate exposure disparities by social vulnerability and quantify the impact of nearby wildfires during pregnancy on birthweight. METHODS Our study population included 139,671 maternal-infant dyads from birth certificate records between 2008 and 2019 in Montana, USA. We classified pregnant people as "exposed” if they had an active, large (≥ 1000 acres) fire within 5 kilometers of their home detected by Moderate Resolution Imaging Spectroradiometer (MODIS) sensors. We characterized the population by neighborhood social vulnerability index (SVI), rurality, and race and estimated associations between nearby fires and birthweight in linear regression analyses adjusted for gestational and maternal age, education, race, parity, prenatal visits, and SVI. RESULTS Exposure to at least one large wildfire within 5 km of home occurred for 0.5% (n=712) of births in Montana between 2008 and 2019. Mean neighborhood SVI as well as rates of both rural residence and American Indian/Alaska Native maternal race were all significantly greater in "exposed” pregnancies. . Having at least one large nearby fire during pregnancy was associated non-significantly with a 21 gram (95% CI: -52.2, 10.2) lower birthweight in adjusted analyses. CONCLUSIONS Social vulnerability appears greater in those experiencing nearby wildfires during pregnancy. Although wildfire exposure within 5 km of home does not appear to influence birthweight, future work should evaluate whether the effects of nearby fires are felt more strongly in socially vulnerable populations. KEYWORDS wildfire, birthweight, social vulnerability, rurality

Detecting short-term stress and recovery events in a vineyard using tower-based remote sensing of photochemical reflectance index (PRI)

Frequent drought and high temperature conditions in California vineyards necessitate plant stress detection to support irrigation management strategies and decision making. Remote sensing provides a powerful tool to continuously monitor vegetation function across spatial and temporal scales. In this study, we utilized a tower-based optical-remote sensing system to continuously monitor four vineyard subplots in California’s Central Valley. We compared the performance of the greenness-based normalized difference vegetation index (NDVI) and the physiology-based photochemical reflectance index (PRI) to track variations of eddy covariance estimated gross primary productivity (GPP) during four stress events between July and September 2020. Our results demonstrate that NDVI was invariant during stress events. In contrast, PRI was effective at tracking the short-term stress-induced declines and recovery of GPP associated with soil water depletion and increased air temperature, as well as reductions in GPP from decreased PAR caused by smokey conditions from nearby fires. Canopy-scale remote sensing can provide continuous real-time data, and physiology-based vegetation indices such as PRI can be used to monitor variation of photosynthetic activity during stress events to aid in management decisions.

Critical longitudinal ventilation velocity for smoke control in a tunnel induced by two nearby fires of various distances: Experiments and a revisited model

Fire smoke in a tunnel fire is a key factor causing casualties, thus the critical longitudinal ventilation velocity is a key parameter in tunnel fire safety ventilation design. The correlation of critical longitudinal ventilation velocity for smoke control in a tunnel induced by two nearby fires has rarely been studied experimentally and quantified before, despite the fact that this scenario exists in practice. In this paper, the critical longitudinal ventilation velocities for smoke control in the tunnel, induced by two nearby fires were experimentally quantified, involving various separation distances between the two fires of both axi-symmetrical and linear sources of various heat release rates, with a total of 72 test conditions. Results show that the effect of separation distance between the two fires on the critical longitudinal ventilation velocity, decreases with the increase of fire heat release rates. The critical longitudinal ventilation velocities are found to firstly decrease with increasing separation distance between the two fires, and then remain unchanged when the separation distance between two fires beyond a critical value. A new modified model, involving two fires of various separation distances, is proposed. The model is shown to well represent the experimental results.

Numerical simulation of thermal response behavior of floating-roof tanks exposed to pool fire

In industrial plants, the fire spread of separative fuel tanks could be related to the tank rupture caused by the thermal radiation from nearby fires. The present paper develops a theoretical framework for analyzing the thermal response behavior and failure time of floating-roof atmospheric storage tanks when exposed to a pool fire. Multi-layer cylindrical flame radiation model is used to predict the radiant heat flux field on the surface of tanks. This radiant heat, considered as the thermal load for a finite element analysis (FEA), influences the tank transient response under thermo-mechanical coupling effects. The paper investigates the respective and combined effects of the tank thermo-physical properties, the non-uniform radiant heat flux distribution, the generated stress as well as the failure time of target tank. For comparative purposes, an empty tank is used as a reference. The results show that the empty and full-filled storage tanks differ in their thermal response modes and their thermos-mechanical behaviors. Within the values in the temperature range of interest adopted for the tank thermo-physical properties, their variations with the temperature have little influence on the tanks’ behavior. The non-uniform radiant heat along the vertical and around circumferential directions of tank has a significant effect on the tanks’ behavior. The stored liquid mediums considerably affect the tanks’ behavior. The failure time of empty tank is over three times as long as that of full-filled storage tank.

SALIENCE AND THE GOVERNMENT PROVISION OF PUBLIC GOODS

This paper examines how behavioral biases caused by salient events affect the government provision of public goods. We develop a theory in which competing communities lobby the government for allocations of a local public good. Salient events bias community demands for the good, which results in inefficient allocations. We empirically test this theory using salient wildfires and government projects to reduce wildfire risk. Wildfires reduce risk to nearby communities, but may increase demand for fuels management projects because of biases induced by salient wildfires. We find that communities experiencing recent nearby fires are more likely to receive fuels management projects. (JELD03, H41, Q24)

Episodes with Anomalously High Black Carbon Concentration in Surface Air in the Region of Tiksi Station, Yakutiya

Measurements (2012–2014) of black carbon (BC) concentration in the surface air in the region of Tiksi International Hydrometeorological Observatory, located near the delta of the Lena River, are analyzed. Variations in the BC concentration with different magnitudes and durations are revealed. Anomalous (larger than 1000 ng/m3) peaks of BC concentration are shown to be rarely encountered, predominately in the warm season of the year (May–September), for no longer than two days. The longest episodes of high BC concentration are associated with long-range atmospheric transport of wildfire products. During such episodes, the air temperature and radiation budget significantly change in the surface atmosphere. The increases in the surface air temperature on days when smoke aerosol comes from nearby fires in July may reach 10°C (at the climatic norm 10–11°C).

Long-term observations of cloud condensation nuclei over the Amazon rain forest – Part 2: Variability and characteristics of biomass burning, long-range transport, and pristine rain forest aerosols

Abstract. Size-resolved measurements of atmospheric aerosol and cloud condensation nuclei (CCN) concentrations and hygroscopicity were conducted over a full seasonal cycle at the remote Amazon Tall Tower Observatory (ATTO, March 2014–February 2015). In a preceding companion paper, we presented annually and seasonally averaged data and parametrizations (Part 1; Pöhlker et al., 2016a). In the present study (Part 2), we analyze key features and implications of aerosol and CCN properties for the following characteristic atmospheric conditions: Empirically pristine rain forest (PR) conditions, where no influence of pollution was detectable, as observed during parts of the wet season from March to May. The PR episodes are characterized by a bimodal aerosol size distribution (strong Aitken mode with DAit ≈ 70 nm and NAit ≈ 160 cm−3, weak accumulation mode with Dacc ≈ 160 nm and Nacc≈ 90 cm−3), a chemical composition dominated by organic compounds, and relatively low particle hygroscopicity (κAit≈ 0.12, κacc ≈ 0.18). Long-range-transport (LRT) events, which frequently bring Saharan dust, African biomass smoke, and sea spray aerosols into the Amazon Basin, mostly during February to April. The LRT episodes are characterized by a dominant accumulation mode (DAit ≈ 80 nm, NAit ≈ 120 cm−3 vs. Dacc ≈ 180 nm, Nacc ≈ 310 cm−3), an increased abundance of dust and salt, and relatively high hygroscopicity (κAit≈ 0.18, κacc ≈ 0.35). The coarse mode is also significantly enhanced during these events. Biomass burning (BB) conditions characteristic for the Amazonian dry season from August to November. The BB episodes show a very strong accumulation mode (DAit ≈ 70 nm, NAit ≈ 140 cm−3 vs. Dacc ≈ 170 nm, Nacc ≈ 3400 cm−3), very high organic mass fractions (∼ 90 %), and correspondingly low hygroscopicity (κAit≈ 0.14, κacc ≈ 0.17). Mixed-pollution (MPOL) conditions with a superposition of African and Amazonian aerosol emissions during the dry season. During the MPOL episode presented here as a case study, we observed African aerosols with a broad monomodal distribution (D ≈ 130 nm, NCN,10 ≈ 1300 cm−3), with high sulfate mass fractions (∼ 20 %) from volcanic sources and correspondingly high hygroscopicity (κ< 100 nm ≈ 0.14, κ>100nm≈ 0.22), which were periodically mixed with fresh smoke from nearby fires (D ≈ 110 nm, NCN,10 ≈ 2800 cm−3) with an organic-dominated composition and sharply decreased hygroscopicity (κ<150nm≈ 0.10, κ>150nm≈ 0.20). Insights into the aerosol mixing state are provided by particle hygroscopicity (κ) distribution plots, which indicate largely internal mixing for the PR aerosols (narrow κ distribution) and more external mixing for the BB, LRT, and MPOL aerosols (broad κ distributions). The CCN spectra (CCN concentration plotted against water vapor supersaturation) obtained for the different case studies indicate distinctly different regimes of cloud formation and microphysics depending on aerosol properties and meteorological conditions. The measurement results suggest that CCN activation and droplet formation in convective clouds are mostly aerosol-limited under PR and LRT conditions and updraft-limited under BB and MPOL conditions. Normalized CCN efficiency spectra (CCN divided by aerosol number concentration plotted against water vapor supersaturation) and corresponding parameterizations (Gaussian error function fits) provide a basis for further analysis and model studies of aerosol–cloud interactions in the Amazon.

Incorporating convective feedback in wildfire simulations using pyrogenic potential

Modelling the dynamics of wildfires is very computationally challenging. Although three-dimensional computational fluid dynamics (CFD) models have been successfully applied to wildfires, the computational time required makes them currently impractical for operational usage. In this study, we develop a two-dimensional propagation model coupled to a ‘pyrogenic’ potential flow formulation representing the inflow of air generated by the fire. This model can accurately replicate features of fires previously unable to be simulated using current two-dimensional models, including development of a fire line into a parabolic shape, attraction between nearby fires and the observed closing behaviour of ‘V’ shaped fires. The model is compared to experimental results with good agreement. The pyrogenic potential model is orders of magnitude faster than a full CFD model, and could be used for improved operational wildfire prediction.

A Review of Community Smoke Exposure from Wildfire Compared to Prescribed Fire in the United States

Prescribed fire, intentionally ignited low-intensity fires, and managed wildfires—wildfires that are allowed to burn for land management benefit—could be used as a land management tool to create forests that are resilient to wildland fire. This could lead to fewer large catastrophic wildfires in the future. However, we must consider the public health impacts of the smoke that is emitted from wildland and prescribed fire. The objective of this synthesis is to examine the differences in ambient community-level exposures to particulate matter (PM2.5) from smoke in the United States in relation to two smoke exposure scenarios—wildfire fire and prescribed fire. A systematic search was conducted to identify scientific papers to be included in this review. The Web of Science Core Collection and PubMed, for scientific papers, and Google Scholar were used to identify any grey literature or reports to be included in this review. Sixteen studies that examined particulate matter exposure from smoke were identified for this synthesis—nine wildland fire studies and seven prescribed fire studies. PM2.5 concentrations from wildfire smoke were found to be significantly lower than reported PM2.5 concentrations from prescribed fire smoke. Wildfire studies focused on assessing air quality impacts to communities that were nearby fires and urban centers that were far from wildfires. However, the prescribed fire studies used air monitoring methods that focused on characterizing exposures and emissions directly from, and next to, the burns. This review highlights a need for a better understanding of wildfire smoke impact over the landscape. It is essential for properly assessing population exposure to smoke from different fire types.

Empirical models of annual post-fire erosion on mulched and unmulched hillslopes

Erosion is one of the primary land management concerns following wildfire. This study examines controls on post-fire hillslope-scale erosion for the 2012 High Park Fire in northern Colorado, develops simple empirical models for predicting post-fire sediment yields, and evaluates model performance on several nearby fires. From 2013 to 2015 we collected ground cover, rainfall, topographic, and sediment yield measurements from 29 convergent hillslopes; eight of these hillslopes had varying amounts of mulch applied to reduce erosion. From these data we examined correlations between annual sediment yield and three categories of predictor variables (ground cover, precipitation, and topography). Percent bare soil was the single largest control on sediment yield, followed by rainfall variables. Sediment yield generally decreased with flow path length, but the correlation was weak. The empirical models each predicted sediment yield with three variables: percent bare soil, one precipitation variable, and one topographic variable. The models had similar accuracy for the High Park Fire using varying combinations of precipitation and topographic variables (Nash-Sutcliffe coefficients 0.70–0.84). An empirical model predicting annual sediment yields as a function of percent bare soil, June–October precipitation, and the maximum flow path length had variable performance when applied to other fires in the same region, with predictions ranging from poor to good for individual fires and Nash-Sutcliffe coefficients of 0.26–0.32 for all fires combined. These tests show some promise for applying the empirical model to fires in the study region, but further model testing is needed to determine the range of conditions under which the model can be applied.

A review of wildland fire smartphone applications

Purpose – Fire management professionals are using smartphone applications to communicate information about wildland fires. The purpose of this paper is to examine English language wildland fire apps available to the general public to learn what information these apps contain and whether they match what are considered characteristics of well-designed apps. Design/methodology/approach – Content analysis of global app markets and other directories revealed ten relevant apps. Two coders installed the apps on identical smartphones and proceeded to review the apps’ content, features, and design characteristics. Findings – Results reveal that the ten English language wildland fire apps on the global app markets fall into three groups: apps that show nearby fires, emergency plan creation apps, and apps that inform on preparedness, response, and recovery. Strengths of these apps include that most load quickly on devices, they offer real-time contextual information, they can be used even when a device is offline, are easy to navigate, and do not utilize processor-intensive animation. Weaknesses include the fact that many lack a search engine, they do not explain how they protect sensitive user data, and they fail to reveal who authors of content are as well as when content was created or modified. Originality/value – Few studies have classified, analyzed content, or assessed the design of wildland fire apps. This study reveals that critical issues app designers should address include ensuring that apps contain privacy policies and disclaimers that app information is not supposed to replace live human advice.

Base Camp Personnel Exposure to Particulate Matter During Wildland Fire Suppression Activities

Wildland fire base camps commonly house thousands of support personnel for weeks at a time. The selection of the location of these base camps is largely a strategic decision that incorporates many factors, one of which is the potential impact of biomass smoke from the nearby fire event. Biomass smoke has many documented adverse health effects due, primarily, to high levels of fine particulate matter (PM2.5). Minimizing particulate matter exposure to potentially susceptible individuals working as support personnel in the base camp is vital. In addition to smoke from nearby wildland fires, base camp operations have the potential to generate particulate matter via vehicle emissions, dust, and generator use. We monitored particulate matter at three base camps during the fire season of 2009 in Washington, Oregon, and California. During the sampling events, 1-min time-weighted averages of PM2.5 and particle counts from three size fractions (0.3–0.5 microns, 0.5–1.0 microns, and 1.0–2.5 microns) were measured. Results showed that all PM size fractions (as well as overall PM2.5 concentrations) were higher during the overnight hours, a trend that was consistent at all camps. Our results provide evidence of camp-based, site-specific sources of PM2.5 that could potentially exceed the contributions from the nearby wildfire. These exposures could adversely impact wildland firefighters who sleep in the camp, as well as the camp support personnel, who could include susceptible individuals. A better understanding of the sources and patterns of poor air quality within base camps would help to inform prevention strategies to reduce personnel exposures.

Biomass smoke exposures: Health outcomes measures and study design

Epidemiological studies of biomass smoke health effects have been conducted in a variety of settings and with a variety of study designs. The Health Effects Workgroup discussed several approaches for the investigation of health effects in communities exposed to wood smoke from nearby wildland fires, intentional agricultural burning, or residential biomass burning devices such as woodstoves or cookstoves. This presentation briefly reviews observational and intervention studies that have been conducted within these exposure settings. The review is followed by a summary of discussion points among the workgroup members with particular emphasis on study design and the use of biomarkers for assessing outcomes in biomass smoke-exposed populations.

Charcoal production, dispersal, and deposition from the Fort Providence experimental fire: interpreting fire regimes from charcoal records in boreal forests

The relationship between charcoal production from fires and charcoal deposition in lakes is poorly understood, which limits the interpretation of sediment charcoal records. This calibration study assessed charcoal particle production, size, and transport during the International Crown Fire Modelling Experiment (ICFME) and compared fossil charcoal particle accumulation from 16 lakes in boreal forests of North America. Particle accumulation averaged 20.1 mm2·cm–2 inside the ICFME fire; accumulation declined sharply outside the fire, with only 1% of the measured particles transported beyond 20 m from the burn edge. Fossil charcoal accumulation during the past 9000 years was much lower than observed deposition in traps located within the ICFME fire but similar to airborne deposition in traps located 10–60 m from the burn edge. A higher fraction of large diameter particles (>1 mm) was present in fossil charcoal accumulation from historical fires and charcoal peaks that exceeded background accumulation by 1.4 times, suggesting large particles are characteristic of nearby fires. On the basis of a charred-particle production of ~2% of the total fuel consumed by the ICFME fire, we estimate a potential long-term carbon sequestration of 58.2 ± 12 g C·m–2 as charred particles from this fire stored in soils or lake sediments.

Multialtitude airborne observations of insolation effects of forest fire smoke aerosols at BOREAS: Estimates of aerosol optical parameters

Forest fire disturbance, as part of the natural cycle of the boreal ecosystem renewal, proved a significant factor in the acquisition scheduling of optical remote imagery at the northern study site of the Boreal Ecosystem‐Atmosphere Study (BOREAS), conducted in northern/central Canada during the July/August months of 1994. One such episode, between July 28 and 31, was due entirely to smoke transported over the study site from nearby and distant downwind fires. Noon insolation was reduced from 800 W/m2 on July 28 to 680 W/m2 on July 31 and incident PAR radiation from 320 to 250 W/m2. During the July 31 smoke episode the compact airborne spectrographic imager (CASI) was flown at 150, 300, 900, 1500, and 3200 m agl over a forested site, while measuring the scene‐reflected radiance as well as upwelling and downwelling irradiances in the spectral range 403 and 916 nm (2.5 nm resolution). These multialtitude observations of upwelling and downwelling irradiance and the hemispherical reflectance are used to estimate at two wavelengths, 550 and 672 nm, the vertical profiles of aerosol optical depth, attenuation coefficient, and single‐scattering albedo representative of the smoke aerosols encountered at BOREAS. For smoke aerosols from distant fires (high altitude) the single‐scattering albedo was 0.9 and the attenuation coefficient was 0.32 km−1 at 672 nm, whereas for smoke aerosols from nearby fires, values of 0.6 and 0.60 km−1 were found. This is qualitatively consistent with differences expected for distant primarily sulfate aerosols and higher soot aerosols for nearby flaming fires.