Wood Stove Research Articles

OS LATERITOS A SERVIÇO DA FÉ: A CATEDRAL NOSSA SENHORA DAS MERCÊS EM PORTO NACIONAL, TOCANTINS

The Nossa Senhora das Mercês cathedral is located in the city of Porto Nacional, Tocantins state. This rustic and impressive church was built on the Tocantins River right margin between the years of 1894 and 1903, by the French Dominican friars, supported by local population efforts. This cathedral exhibits a romanesque architectural style being constructed using local raw materials, mainly lateritic fragments (ferruginized sandstones), ceramic bricks and mortar prepared with soil, wood stove ashes and grasses. Despite of the well-known high chemical stability of these rocks due to iron oxides and hydroxides minerals composition, some deterioration features were observed, as for example, the vegetation and micro-organisms communities growing on the surface of cathedral external walls, among other findings. Such biological activity promotes the weathering acceleration leading to detachment of building materials. To foment the preventive maintenance and the proper use of restoration materials and techniques, it is imperative to carry out studies about the geological provenance, chemical and mineralogical characteristics of these constructive materials.

Monitoring indoor air quality using smart integrated gas sensor module (IGSM) for improving health in COPD patients.

Technology advancement, industrialisation, and globalisation have been significant reasons for air pollution outdoors and indoors. It may surprise us that we spend about 80% of our time indoors breathing toxic, stale, polluted air, making us sluggish and fretful. In contrast to outdoor air, indoor air does not recycle consistently. It traps and builds pollutants from wood and coal stoves, furniture and building materials, paints and solvents, cigarette smoke, and cleaning supplies. The prolonged exposure to these hidden pollutants can prompt respiratory disorders such as lung disease, pneumonitis, asthma, pulmonary hypertension, and chronic obstructive pulmonary disease (COPD). It is enduring and is not curable, which has been a threat to humanity for ages. COPD's major cause is airborne particulate matter and other toxic compounds emitted from indoor and outdoor sources. Outdoor air pollution can be controlled only by acquiring changes in the vast population, wherein for indoor, every individual may create a major impact on improving air purity, thereby promoting health. The proposed design model for monitoring indoor air quality was tested in a normal and stimulating environment where we live. Parameters tested included temperature, humidity, amount of PM2.5, and the concentration of CO, CO2, and NH3. These parameters were monitored for five to 6 h per day for 8 days. Results indicate that the total air quality lies in the moderate range. Further study will be helpful to utilise this module as an effective Indoor air quality (IAQ) monitoring system. HIGHLIGHTS: • A simple, effective, inexpensive integrated gas sensor module (IGSM) has been proposed in this study to monitor the indoor air quality index (IAQI). • Indoor air quality was tested in a normal and stimulating environment for 8 days. • The integrated gas sensor module (IGSM) was composed of sensors in series, and the outputs for the respective parameter were measured easily. • Among the parameters tested, CO and PM2.5 lie in the moderate range, while other pollutants within the normal range reveal that the tested air quality is moderate.

Numerical investigations of soot generation during wood-log combustion

• Particle-scale biomass combustion model with soot formation is established. • Virtual-particle-based thermally-thick model and two-equation soot model are integrated. • Improved prediction of soot volume fraction for a single-particle combustion experiment is achieved. • Soot generation during wood log combustion depends highly on flame structure and the packing of wood logs. Soot formation is an important challenge in the design of modern wood stoves, as soot not only deteriorates the combustion efficiency but also poses threats to human health. Although soot formation in biomass combustion has been studied previously, the investigation at wood stove level is still rare due to its complex nature. In this paper, numerical simulations are performed to uncover the basic trends of soot formation during wood log combustion. The soot formation model is developed based on a particle-resolved biomass combustion algorithm, where the intraparticle heat and mass transfer effect, soot mass fraction and particle size are all resolved. Besides, simplified tar and precursor models are used in solving the reaction kinetics of soot formation. The integrated model is first validated through the combustion simulation of a micron-sized coal particle in air, where the predicted flame temperature and the soot volume fraction show improved agreement with experimental data compared to a previous modeling work. Thereafter, the soot formation during wood-log combustion in a confined stove is studied. Different combustion behaviors are observed for varying numbers of wood logs and for variations in the wood-log stacking. Additionally, the flow field temperature, tar, soot, and oxygen concentrations during the combustion are analyzed. Finally, the influences of the air intake rate, the relative distance between wood logs, and temperature boundary condition on the soot formation are discussed. This work provides useful information for the design and the optimization of modern wood stoves.

Effect of tree species on the elemental composition of wood ashes and their fertilizer values on agricultural soils

AbstractWood ashes obtained from household heating and cooking are often applied to home gardens and arable fields by farmers. The effect of tree species and their locations on the elemental composition of wood ashes derived from domestic cooking and heating is unknown. The study aimed to discover the fertilizer values of wood ashes obtained from Betula pendula, Carpinus betulus, Fagus sylvatica, Larix decidua, Picea abies, Pinus sylvestris, Quercus robur, and Tilia cordata from two different localities, Hlinsko and Mšec, Czech Republic. The total element content in the ashes of dry wood samples (wood and bark) burnt at 460°C with a wood stove interfaced with a thermometer was determined using portable x‐ray spectrometry. The content (in g kg−1) of P (3.23–20.53), K (26.79–136.22), Ca (94.89–295.56), and S (2.97–11.75) in the ashes varies according to the tree species, locality, parent rock, and anthropogenic activities in the location of trees. Additionally, trace element contents ranged from 0.63–32.07 g Mn kg−1, 0.34–4.6 g Fe kg−1, 32.4–2062 mg Zn kg−1, 47.61–193.09 mg Cu kg−1, 3.99–21.53 mg Mo kg−1, and 1.50–6.62 mg Se kg−1. The pH of the ashes ranged from 8.71 to 11.54, suitable to alleviate soil acidity and a condition satisfying soil additive. A significant positive correlation between the contents of Cu, Sr, and Pb with the ashes of Picea abies, Larix decidua, Pinus sylvestris, and Betula pendula at Hlinsko is indicative of ancient anthropogenic activities input in the soil. The combustion of wood under home heating temperatures resulted in the concentration of most risk metal(loid)s, below permissible limits in agricultural soils. Application of wood ashes on arable fields requires considerable caution due to potentially toxic elements (Zn and Pb).

Cleaning the Flue in Wood-Burning Stoves Is a Key Factor in Reducing Household Air Pollution.

In experimental settings, replacing old wood stoves with new wood stoves results in reduced personal exposure to household air pollution. We tested this assumption by measuring PM2.5 and levoglucosan concentrations inside homes and correlated them with wood stove age. Methods: Thirty homes in the Albuquerque, NM area were monitored over a seven-day period using in-home particulate monitors placed in a common living area during the winter months. Real-time aerosol monitoring was performed, and filter samples were analyzed gravimetrically to calculate PM2.5 concentrations and chemically to determine concentrations of levoglucosan. A linear regression model with backward stepwise elimination was performed to determine the factors that would predict household air pollution measures. Results: In this sample, 73.3% of the households used wood as their primary source of heating, and 60% burned daily or almost daily. The mean burn time over the test week was 50 ± 38 h, and only one household burned wood 24/day (168 h). The average PM2.5 concentration (standard deviation) for the 30 homes during the seven-day period was 34.6 µg/m3 (41.3 µg/m3), and median (min, max) values were 15.5 µg/m3 (7.3 µg/m3, 193 µg/m3). Average PM2.5 concentrations in 30 homes ranged from 0–15 μg/m3 to >100 μg/m3. Maximum PM2.5 concentrations ranged from 100–200 μg/m3 to >3000 μg/m3. The levoglucosan levels showed a linear correlation with the total PM2.5 collected by the filters (R2 = 0.92). However, neither mean nor peak PM2.5 nor levoglucosan levels were correlated with the age (10.85 ± 8.54 years) of the wood stove (R2 ≤ 0.07, p > 0.23). The final adjusted linear regression model showed that average PM2.5 was associated with reports of cleaning the flue with a beta estimate of 35.56 (3.47–67.65) and R2 = 0.16 (p = 0.04). Discussion: Cleaning the flue and not the wood stove age was associated with household air pollution indices. Education on wood stove maintenance and safe burning practices may be more important in reducing household air pollution than the purchase of new stoves.

CHEMISTRY IN NON-SCHOOL SPACES

INTRODUCTION: Access to basic education has advanced a lot with educational policies that have made possible disciplines such as chemistry present in the environment where we live in the school routine. OBJECTIVE: The aim was to observe from the point of view of students in the 9th year of an elementary school in a resident settlement in the extreme south of Bahia. MATERIALS AND METHODS: RESULTS: Through a descriptive and qualitative observation research, carried out during the application of the curricular component of chemistry. It was observed that in their homes, it is present in substances such as water, chlorine, soap, and inorganic foods, animal husbandry, chemistry is part of the balance of development, in the community, electricity, television and radio, of cooking gas and wood stoves, as well as the balance in minimizing zoonoses that affect animal and human life. CONCLUSION: Therefore, chemistry involves much more than complex concepts and calculations, it is a collection of the whys of reactions, phenomena within the daily life of each student.

Assessing the indoor air quality and their predictor variable in 21 home offices during the Covid-19 pandemic in Norway

In this study, concentrations of pollutants: formaldehyde, carbon dioxide (CO2), and total volatile organic compounds (TVOC) and parameters: indoor room temperature and relative humidity (RH) were measured in 21 home offices for at least one week in winter in Trondheim, Norway. Eleven of these were measured again for the same duration in summer. Potentially explanatory variables of these parameters were collected, including building and renovation year, house type, building location, trickle vent status, occupancy, wood stove, floor material, pets, RH, and air temperature.The association between indoor air pollutants and their potential predictor variables was analyzed using generalized estimation equations to determine the significant parameters to control pollutants. Significantly seasonal differences in concentrations were observed for CO2 and formaldehyde, while no significant seasonal difference was observed for TVOC. For TVOC and formaldehyde, trickle vent, RH, and air temperature were among the most important predictor variables. Although higher concentrations of CO2 were measured in cases where the trickle vent was closed, the most important predictor variables for CO2 were season, RH, and indoor air temperature.The formaldehyde concentrations were higher outside working hours but mostly below health thresholds recommendations; for CO2, 11 of the measured cases had indoor concentrations exceeding 1000 ppm in 10% of the measured time. For TVOC, the concentrations were above the recommended values by WHO in 73% of the cases. RH was generally low in winter. The temperature was generally kept over the recommended level of 22–24 °C during working hours.

Long-term trends in particulate matter from wood burning in the United Kingdom: Dependence on weather and social factors

Particulate matter from wood burning emissions (Cwood) was quantified at five locations in the United Kingdom (UK), comprising three rural and two urban sites between 2009 and 2021. The aethalometer method was used. Mean winter Cwood concentrations ranged from 0.26 μg m−3 (in rural Scotland) to 1.30 μg m−3 (London), which represented on average 4% (in rural environments) and 5% (urban) of PM10 concentrations; and 8% of PM2.5. Concentrations were greatest in the evenings in winter months, with larger evening concentrations in the weekends at the urban sites. Random-forest (RF) machine learning regression models were used to reconstruct Cwood concentrations using both meteorological and temporal explanatory variables at each site. The partial dependency plots indicated that temperature and wind speed were the meteorological variables explaining the greatest variability in Cwood, with larger concentrations during cold and calm conditions. Peaks of Cwood concentrations took place during and after events that are celebrated with bonfires. These were Guy Fawkes events in the urban areas and on New Year's Day at the rural sites; the later probably related to long-range transport. Time series were built using the RF. Having removed weather influences, long-term trends of Cwood were estimated using the Theil Sen method. Trends for 2015–2021 were downward at three of the locations (London, Glasgow and rural Scotland), with rates ranging from −5.5% year−1 to −2.5% year−1. The replacement of old fireplaces with lower emission wood stoves might explain the decrease in Cwood especially at the urban sites The two rural sites in England observed positive trends for the same period but this was not statistically significant.

Cooking Vessels in Ancient Literature

The lives of the Sangam people are recorded in the literature of that time. The elements of the lives of people vary in many ways due to factors such as climate, politics, economy, religion, language, race, etc. The goods which are in circulation, i.e., in use in people's lives, are called "utility vessels." Utility vessels can be classified on the basis of their uses as cooking, eating, storage, or consumables. There are many utility vessels available at home. It is noteworthy that most of the items are related to cooking and food. "Cooking Vessel" refers to the vessels used in the kitchen or the cooking house. From the Sangam period till the 16th and 17th centuries, stoves like stone stoves, wood stoves, and husk stoves were mostly used. Mada (Large earthen vessel), Thudupu (Spatula), Talam (Tray), Kaal (Firewood), Naarari (Sieve), Matthu (churning rod), Ammi (grinding stone), Ural (Mortar), Ulakkai (Pestle), Trikai (quern), Sulaku (winnowing fan), etc. are traces of civilization. The mortar is a combination of two things: stone tools that are something to hold in the hand and a base. The use of many utility vessels for cooking can be determined based on their usage. Many of the cooking vessels used by the Sangam people have become scarce today. The vessels used in the kitchen are now lined up in the hall as decorative items. This study researches such utility vessels that are used in the kitchen or cooking houses.

The Performance and Emission Parameters Based on the Redistribution of the Amount of Combustion Air of the Wood Stove

Several factors affect how particulate matter and gaseous emissions are formed during the combustion processes of biomass. The amount of combustion air, as well as its redistribution, is one of these factors. This article deals with the performance and emission parameters determined using different distributions of the amount of combustion air of the wood stove with beech wood as a fuel. Eighteen different settings of primary, secondary and tertiary air supplies were realized, while heat output, efficiency, particulate matter, carbon monoxide and nitrogen oxides were measured or determined. The aim of this article is to identify the optimal air distribution between primary, secondary, and tertiary air supplies focused on the mentioned parameters. Based on the results, two settings (25/50/25 and 0/100/0) could be the optimal variant. However, the concentration of particulate matter reached a higher value during the setting with a ratio of 25/50/25, similar to a ratio of 50/25/25. The measurement during the setting with a ratio of 0/100/0 could be influenced by the existing embers on the grid before the start of the measurement. However, it is important to supply all three types of combustion air with the main emphasis on the secondary air supply due to the completely use of the combustible gases.

Development of an integrated duty cycle test method to assess cordwood stove performance

ABSTRACT The US Environmental Protection Agency’s (EPA’s) New Source Performance Standards (NSPS) for Residential Wood Heaters (RWH) require certification emission testing of prototype appliances. In 2015, EPA revised those standards to further reduce particulate matter emissions from this critical source. However, to achieve that goal, lower emissions measured in certification tests must reflect lower emissions when the appliance is operated in homes. Woodstove certification tests have used either the Federal Reference Method (FRM), a crib wood method, or a cordwood testing method developed by ASTM International that was designated as a broadly applicable Alternative Test Method (ATM) by the EPA until December 2021, when that status was revoked. There is broad agreement that the FRM and ASTM procedures do not simulate typical fueling and operating of wood stoves in the field, raising questions about the efficacy of the current program. Effective emission reduction efforts require robust, accurate, and reproducible test methods. With input from a range of stakeholders, the Northeast States for Coordinated Air Use Management (NESCAUM) developed the Integrated Duty Cycle Test Method for Certification of Wood-Fired Stoves Using Cordwood (IDC), a cordwood testing protocol designed to improve the efficacy of residential wood heater certification testing. That method was approved by EPA as a broadly applicable ATM in 2021. IDC test runs assess appliance performance under a range of operating and fueling conditions representative of typical consumer use patterns. Unlike previous test methods, the IDC protocol requires three replicate runs to assess appliance performance variability. Including variable fueling and operating conditions, along with the requirement for replicates runs, will increase the effectiveness of certification testing and promote the development of improved wood stove technology. This paper reports on experiments conducted to develop and test the IDC method. Implications: Residential wood heating is one of the largest sources of primary particulate matter pollution nationwide. EPA’s New Source Performance Standards (NSPS) establish emission limits for this source category and require certification testing of prototype wood appliances to demonstrate compliance with those limits. However, the operating and fueling requirements in NSPS compliance testing protocols do not represent typical conditions in the field. We developed a new testing approach, the Integrated-Duty Cycle (IDC) Test Method, to address the shortcomings of current certification test approaches. The IDC procedure for cordwood stoves, which was approved by EPA as a broadly applicable alternative test method in 2021, assesses appliance operations over various operating and fueling conditions representing typical consumer use patterns in an integrated run and requires three replicate runs to enable the assessment of variability in stove performance. Stoves certified with this method will be equipped to meet the NSPS limits consistently in field operation.

Residential wood heating: An overview of U.S. impacts and regulations

ABSTRACT Air pollution from residential wood heating poses a significant public health risk and is a primary cause of PM nonattainment in some areas of the United States. Those emissions also play a role in regional haze and climate change. While regulatory programs have focused on emissions reductions from large facilities, the residential heating sector has received limited attention. The failure to develop effective programs to address this emission source hampers the ability of state and local air quality programs to meet clean air goals. An updated New Source Performance Standard (NSPS) for Residential Wood Heaters was promulgated in 2015, which includes more stringent emissions standards for wood stoves and broadens its scope to regulate additional types of wood heating appliances. However, weaknesses in the test methods and programs used to certify compliance with the NSPS limits hamper the efficacy of those requirements. Current emissions certification tests measure stove performance under defined laboratory conditions that (1) do not adequately reflect operation and performance of appliances in homes, (2) are not sufficiently repeatable to allow for comparison of emissions of different appliances, and (3) allow manufacturers leeway to modify critical test fueling and operating parameters which can significantly impact performance outcomes. These foundational regulatory issues present substantial challenges to promoting the cleanest and most efficient wood heating systems. This paper provides an overview of the air quality and public health impacts of residential wood heating and discusses the weaknesses in the current emission certification approaches and work by the Northeast States for Coordinated Air Use Management (NESCAUM) and the New York State Energy Research and Development Authority to develop improved testing methods. Other articles in this issue discuss the development and testing of those methods in detail. Implications: Air pollution from residential wood heating poses a significant public health risk and is a primary cause of PM nonattainment in some areas of the United States. Those emissions also play a role in regional haze and climate change. While regulatory programs have focused on emissions reductions from large facilities, the residential heating sector has received limited attention. The failure to develop effective programs to address this emission source hampers the ability of state and local air quality programs to meet clean air goals. This paper provides an overview of the issue.

Realistic operation of two residential cordwood-fired outdoor hydronic heater appliances—Part 2: Particle number and size

ABSTRACT The use of wood as a fuel for home heating is a concern from an environmental health and safety perspective as biomass combustion appliances emit high concentrations of particulate matter. Wood burning significantly contributes to wintertime particulate matter concentrations in many states in the northern United States. Of particular concern are outdoor wood-fired hydronic heaters. These devices are concerning as they tend to have very large combustion chambers and typical use patterns can result in long periods of low output, which result in an increased particulate matter emission rate relative to high heat output operating conditions. In this study, the performance of two hydronic heaters operating under different combustion conditions, including four different heat output categories approximately corresponding to categories I–IV denoted in Environmental Protection Agency Method 28 Outdoor Wood-fired Hydronic Heaters, and during start-up and reloading events were investigated. Measurements of flue gas particulate number concentration and size for particles with aerodynamic diameters between 0.006 and 10 µm were made using a dilution sampling system. The measured particle number concentration in the flue gas was between 0.71 and 420 million particles per cubic centimeter and was dependent on fuel loading and heat output. For each hydronic heater tested, the highest average particle concentration was found at the beginning of each test during the cold-start condition. Additionally, the majority of the particles had aerodynamic diameters less than 0.100 µm (particles of this size made up between 64% and 97% of all particles) and less than 1% of all particles had aerodynamic diameters greater than 1 µm for all phases. For particles in the accumulation mode, between 0.100 and 1 µm, the mean particle diameter was dependent on fuel loading and heat output. Implications: In this work, we provide information on the particle number concentration and particle size of emissions from outdoor cord- wood-fired hydronic heaters. Wood-fired hydronic heater data is sparsely available compared to wood stove data. Thus, additionaldata from this source help to inform the work of modelers and policy makers interested in hydronic heaters. The test method used in this work is also novel, as it is more inclusive of real-world use cases than the current certification method. Our data helps to validate the test method and allows for comparisons between real-world use case scenarios, and idealized test cases.

Efficacy of air filtration and education interventions on fine particulate matter among rural Native American homes heated with wood stoves: Results from the EldersAIR randomized trial

BackgroundNative Americans living in rural areas often rely upon wood stoves for home heating that can lead to elevated indoor concentrations of fine particulate matter (PM2.5). Wood stove use is associated with adverse health outcomes, which can be a particular risk in vulnerable populations including older adults. ObjectivesWe assessed the impact of portable air filtration units and educational approaches that incorporated elements of traditional knowledge on indoor and personal PM2.5 concentrations among rural, Native American elder households with wood stoves. MethodsEldersAIR was a three-arm, pre-post randomized trial among rural households from the Navajo Nation and Nez Perce Tribe in the United States. We measured personal and indoor PM2.5 concentrations over 2-day sampling periods on up to four occasions across two consecutive winter seasons in elder participant homes. We assessed education and air filtration intervention efficacy using linear mixed models. ResultsGeometric mean indoor PM2.5 concentrations were 50.5 % lower (95 % confidence interval: −66.1, −27.8) in the air filtration arm versus placebo, with similar results for personal PM2.5. Indoor PM2.5 concentrations among education arm households were similar to placebo, although personal PM2.5 concentrations were 33.3 % lower for the education arm versus placebo (95 % confidence interval: −63.2, 21.1). SignificanceThe strong partnership between academic and community partners helped facilitate a culturally acceptable approach to a clinical trial intervention within the study communities. Portable air filtration units can reduce indoor PM2.5 that originates from indoor wood stoves, and this finding was supported in this study. The educational intervention component was meaningful to the communities, but did not substantially impact indoor PM2.5 relative to placebo. However, there is evidence that the educational interventions reduced indoor PM2.5 in some subsets of the study households. More study is required to determine ways to optimize educational interventions within Native American communities.

A Critical Review and Discussion on Emission Factors for Wood Stoves

A Critical Review and Discussion on Emission Factors for Wood Stoves

Don't extinguish my fire – Understanding public resistance to a Swedish policy aimed at reducing particle emissions by phasing out old wood stoves

Wood stoves emit particulate matter when used for domestic heating. Consequently, the National Board of Housing, Building and Planning in Sweden enforced a prohibition of new installations of old wood stoves in 2017 to protect the public health. The prohibition caused a public backlash that organized itself as a “wood stove rising”, eventually leading to a cancellation of the new legislation in 2019. We performed comprehensive interviews with 11 signatories of the original appeal to analyze the underlying motives for combating the implementation of this pro-environmental energy policy. We find that domestic heating through fire-making is an age-old human behavior that is deeply connected to several social and emotional human needs, but also to survival in remote areas with cold climate. The likelihood of policy observance and acceptance is higher if the policy is not perceived as being in direct conflict with these needs: basic emotion regulation, sensations of tradition and connection to other people, and means of crisis management for the individual. We also find that the protesters acted out of a sustainability perspective, albeit one where the continued use of functional devices was valued more than the perceived wear-and-tear of replacing outdated technology.

Determination of Arrhenius parameters for advanced kinetic model used in CFD modeling of the wood pellet combustion process

With the increased popularity of using wood stoves for household heating in recent years, numerous experimental research projects have been launched with the goal of generating cleaner and more efficient stove designs. This work is focused on mathematical modeling of combustion process in low-power residential heating appliance (small-scale stove) fuelled by different wood pellets (WP1-Beech (hardwood) and WP2-Pine (softwood)). Kinetic model scheme that encompasses determination of Arrhenius parameters was proposed for applied Finite rate/Eddy Dissipation approach. Types of wood pellets have been combusted on the experimental stand which is equipped with a set of temperature sensors and exhaust analyzer. A comparison of results obtained from combustion in the heating unit has been performed to find relations between established kinetics of devolatilization for various wood pellets and to determine exhaust composition, arising from oxidation reactions. Numerical modeling using computational fluid dynamics (CFD) has been performed for the char and CO oxidations to supplement the experimental results. Due to limitations on installed stove such as poor design, air supply, fume extraction, or heat exchanger can lead to excessive CO emissions or lower energy efficiency. Outcomes show that it is crucial to minimize unused stove volume and to enhance gaseous mixing for reduction of CO emissions, while maintaining sufficiently high temperatures for supporting fast oxidation reactions. Results of comparisons of conducted analyses can be useful in areas related to process optimization and improvement of combustion and devolatilization reaction conditions in the small scale heating units.

Efficacy of Air Filtration and Education Interventions on Indoor Fine Particulate Matter and Child Lower Respiratory Tract Infections among Rural U.S. Homes Heated with Wood Stoves: Results from the KidsAIR Randomized Trial.

Background:Millions of rural U.S. households are heated with wood stoves. Wood stove use can lead to high indoor concentrations of fine particulate matter [airborne particles in aerodynamic diameter ()] and is associated with lower respiratory tract infection (LRTI) in children.Objectives:We assessed the impact of low-cost educational and air filtration interventions on childhood LRTI and indoor in rural U.S. homes with wood stoves.Methods:The Kids Air Quality Interventions for Reducing Respiratory Infections (KidsAIR) study was a parallel three-arm (education, portable air filtration unit, control), post-only randomized trial in households from Alaska, Montana, and Navajo Nation (Arizona and New Mexico) with a wood stove and one or more children of age. We tracked LRTI cases for two consecutive winter seasons and measured indoor over a 6-d period during the first winter. We assessed results using two analytical frameworks: a) intervention efficacy on LRTI and (intent-to-treat), and b) association between and LRTI (exposure–response).Results:There were 61 LRTI cases from 14,636 child-weeks of follow-up among 461 children. In the intent-to-treat analysis, children in the education arm [; 95% confidence interval (CI): 0.35, 2.72] and the filtration arm (; 95% CI: 0.46, 3.32) had similar odds of LRTI vs. control. Geometric mean concentrations were similar to control in the education arm (11.77% higher; 95% CI: , 49.72) and air filtration arm (6.96% lower; 95% CI: , 24.55). In the exposure–response analysis, odds of LRTI were 1.45 times higher (95% CI: 1.02, 2.05) per interquartile range () increase in mean indoor .Discussion:We did not observe meaningful differences in LRTI or indoor in the air filtration or education arms compared with the control arm. Results from the exposure–response analysis provide further evidence that biomass air pollution adversely impacts childhood LRTI. Our results highlight the need for novel, effective intervention strategies in households heated with wood stoves. https://doi.org/10.1289/EHP9932

Inflammatory markers and lung function in relation to indoor and ambient air pollution.

Ambient air pollution causes a range of adverse health effects, whereas effects of indoor sources of air pollution are not well described in high-income countries. We compared hazards of ambient air pollution and indoor sources with respect to important biomarkers of cardiorespiratory effects in terms of lung function and systemic inflammation in a middle-aged Danish cohort. Our cohort comprised 5199 men and women aged 49-63 years at the recruitment during April 2009 to March 2011, with information on exposure to second-hand smoke (SHS) and use of candles, wood stove, kerosene heater and gas cooker as well as relevant covariates. Ambient air pollution exposure was assessed as 2-year mean nitrogen dioxide (NO2) at the address (mean±SD: 17.1±9.9μg/m3) and 4-day average levels of particulate matter with diameter <2.5μm (PM2.5; mean±SD: 12.5±6.0μg/m3) in urban background. Lung function was assessed as % predicted forced expiratory volume in the first second (FEV1) and inflammatory markers comprised interleukin-6 (IL-6), IL-10, IL-18, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), and high sensitivity C-reactive protein (hs-CRP). We used random-effect regression models controlling for potential confounders as well as models with further adjustment for self-reported health or for all other exposures. In models adjusted for confounders FEV1 was inversely associated with exposure to NO2, (-0,83% per 10μg/m3; 95% CI: -1.26; -0.41%), SHS (-0.56% per 1 of 5 categories increment; 95% CI: -0.89; -0.23%), and gas cooker without hood (-0.89%; 95% CI: -1.62; -0.17%), whereas use of wood stove and candles showed positive associations, although these attenuated by mutual adjustment for all exposures or self-reported health. IL-6 showed positive associations with NO2 (6.30% increase in log-transformed values per 10μg/m3; 95% CI: 3.54; 9.05%), PM2.5 (7.82% per 10μg/m3; 95% CI: 3.35; 12.4%), SHS (4.38% per increase of 1 of 5 categories; 95% CI: 2.22; 6.54%) and use of kerosene (13.8%; 95% CI: 2.51; 25.1%), whereas the associations with use of wood stove and candles were inverse. PM2.5 and NO2 showed positive associations with IFN-γ and TNF-α, while PM2.5 further associated with IL-10 and IL-18. Hs-CRP was inversely associated with use of candles. These results suggest that the levels of exposure to ambient air pollution and SHS are more harmful than are the levels of exposure to indoor combustion sources from candles and wood stoves in a high-income setting.

Impact of Residential Real-World Wood Stove Operation on Air Quality concerning PM2.5 Immission

In Germany, the number of small wood-burning combustion plants was around 11 million in 2020. The PM2.5 immissions caused by the operation of these combustion plants are already about as high as those from traffic exhaust gases. Thus, particulate matter immissions occur not only on busy roads but also in residential areas. Since there are few official measuring stations for PM2.5 in residential areas and suburbs, this study determined PM2.5 concentrations from November 2020 to June 2021 at three stations (urban, suburban, and residential) in the Karlsruhe area. Simultaneous measurements of PM2.5 at the three locations have been implemented to determine short-term (peaks), medium-term, and long-term particulate matter levels and to assign them to sources by observation, considering wind direction. Illustratively, PM2.5 immission levels in January and May 2021 were compared in this paper. The comparison of the particulate matter immissions measured in the urban and residential area in January revealed that PM2.5 concentration peaks of up to 60 µg/m3 occurred for short periods in the residential area, especially on Fridays and in the evenings, which could be assigned to wood stove operation. In the urban and suburban areas, the number of the immission peaks was lower by 70–80%, and the peak concentrations were also lower by an average of 13–18%. However, the high short-term peaks have no significant impact when calculating the PM2.5 annual average according to the current limit value regulation (39. BImSchV).