Usage and impacts of the Envirofit HM‐5000 cookstove

Burning solid fuels to fulfill daily household energy needs results in chronic exposure to household air pollution (HAP), which is among the world's greatest health risks. This paper presents the results of a cross‐sectional study of cookstove usage, fuel consumption, and indoor PM_2.5 concentrations in rural and urban Honduran homes cooking with the Envirofit HM‐5000 metal plancha stove (n = 32) as compared to control households using baseline cooking technologies (n = 33). Temperature‐based stove usage measurements showed high HM‐5000 acceptance, with significant displacement of the traditional cookstoves at both the urban (99%, P < .05) and rural study sites (75%, P < .05). However, longer‐term usage data collected in peri‐urban households showed that participants cooked on the HM‐5000 more frequently during the 3‐day monitoring period than during the following 3 weeks. Average indoor PM_2.5 was 66% lower in HM‐5000 households as compared to control households (P < .05). Lower indoor PM_2.5 concentrations observed in participant homes as compared to control households, supported by high usage and traditional stove displacement, suggest the potential for the HM‐5000 to yield health improvements in adopting Honduran households.     

Provision of Disability Adaptations to the Home: Analysis of Household Survey Data

The move towards greater provision of healthcare at home has been a significant policy intention for the past two decades [Ham, C., Dixon, A., & Brooke, B. (2012) Transforming the Delivery of Health and Social Care: The Case for Fundamental Change (London: Kings Fund)]. Key to this ambition is the need to provide suitable accommodation for disabled households by installing a range of possible adaptations. Using data from English Housing Surveys of 2003/2004 and 2009/2010, we compare levels of the provision of adaptations with a number of socio-cultural variables, and report on some significant correlations. This includes most importantly, bias against non-white disabled households and younger disabled households, a significant link between rented accommodation and disabled households, and a worrying increase in the proportion of adaptations deemed by the householders to be ‘not needed’, from 7 to 25 per cent, over that 6-year time period. We discuss the context of these results and conclude with an outline plan for future research, which is urgently needed to verify and understand the issues raised.     

Determinants of winter indoor temperatures in low income households in England

The objective of this study is to quantify the extent to which variation in heating season indoor temperatures is explained by dwelling and household characteristics and increased by energy efficiency improvements in low income households. A survey of dwellings in the Warm Front home energy efficiency scheme was carried out in five urban areas of England. Half-hourly living room and main bedroom temperatures were recorded for 2–4 weeks over two winters. For each dwelling, regression of indoor on outdoor temperature was used to obtain estimates of daytime living room and night time bedroom temperatures under standardized conditions (outdoor temperature of 5 °C). The results indicate that the median standardized daytime living room temperature was 19.1 °C and the median standardized night time bedroom temperature 17.1 °C. Temperatures were influenced by property characteristics, including its age, construction and thermal efficiency and also by the household number of people and the age of the head of household. Dwellings that received both heating and insulation measures through the Warm Front scheme had daytime living room temperatures 1.6 °C higher than pre-intervention dwellings, night time bedroom temperatures were 2.8 °C higher. Warm Front energy efficiency improvements lead to substantial improvements of both living room and bedroom temperatures which are likely to have benefits in terms of thermal comfort and well-being.     

Developing a predictive model for fine particulate matter concentrations in low socio‐economic households in Durban,South Africa

In low‐resource settings, there is a need to develop models that can address contributions of household and outdoor sources to population exposures. The aim of the study was to model indoor PM_2.5 using household characteristics, activities, and outdoor sources. Households belonging to participants in the Mother and Child in the Environment (MACE) birth cohort, in Durban, South Africa, were randomly selected. A structured walk‐through identified variables likely to generate PM_2.5. MiniVol samplers were used to monitor PM_2.5 for a period of 24 hours, followed by a post‐activity questionnaire. Factor analysis was used as a variable reduction tool. Levels of PM_2.5 in the south were higher than in the north of the city (P < .05); crowding and dwelling type, household emissions (incense, candles, cooking), and household smoking practices were factors associated with an increase in PM_2.5 levels (P < .05), while room magnitude and natural ventilation factors were associated with a decrease in the PM_2.5 levels (P < .05). A reasonably robust PM_2.5 predictive model was obtained with model R² of 50%. Recognizing the challenges in characterizing exposure in environmental epidemiological studies, particularly in resource‐constrained settings, modeling provides an opportunity to reasonably estimate indoor pollutant levels in unmeasured homes.     

The effects of bedroom air quality on sleep and next‐day performance

The effects of bedroom air quality on sleep and next‐day performance were examined in two field‐intervention experiments in single‐occupancy student dormitory rooms. The occupants, half of them women, could adjust an electric heater to maintain thermal comfort but they experienced two bedroom ventilation conditions, each maintained for 1 week, in balanced order. In the initial pilot experiment (N = 14), bedroom ventilation was changed by opening a window (the resulting average CO₂ level was 2585 or 660 ppm). In the second experiment (N = 16), an inaudible fan in the air intake vent was either disabled or operated whenever CO₂ levels exceeded 900 ppm (the resulting average CO₂ level was 2395 or 835 ppm). Bedroom air temperatures varied over a wide range but did not differ between ventilation conditions. Sleep was assessed from movement data recorded on wristwatch‐type actigraphs and subjects reported their perceptions and their well‐being each morning using online questionnaires. Two tests of next‐day mental performance were applied. Objectively measured sleep quality and the perceived freshness of bedroom air improved significantly when the CO₂ level was lower, as did next‐day reported sleepiness and ability to concentrate and the subjects' performance of a test of logical thinking.     

Housing characteristics and indoor air quality in households of Alaska Native children with chronic lung conditions

Alaska Native children experience high rates of respiratory infections and conditions. Household crowding, indoor smoke, lack of piped water, and poverty have been associated with respiratory infections. We describe the baseline household characteristics of children with severe or chronic lung disease participating in a 2012–2015 indoor air study. We monitored indoor PM2.5, CO₂, relative humidity %, temperature, and VOCs and interviewed caregivers about children's respiratory symptoms. We evaluated the association between reported children's respiratory symptoms and indoor air quality indicators using multiple logistic regression analysis. Compared with general US households, study households were more likely overcrowded 73% (62%–82%) vs 3.2% (3.1%–3.3%); had higher woodstove use as primary heat source 16% (9%–25%) vs 2.1% (2.0%–2.2%); and higher proportion of children in a household with a smoker 49% (38%–60%) vs 26.2% (25.5%–26.8%). Median PM2.5 was 33 μg/m³. Median CO₂ was 1401 ppm. VOCs were detectable in all homes. VOCs, smoker, primary wood heat, and PM2.5>25 μg/m³ were associated with higher risk for cough between colds; VOCs were associated with higher risk for wheeze between colds and asthma diagnosis. High indoor air pollutant levels were associated with respiratory symptoms in household children, likely related to overcrowding, poor ventilation, woodstove use, and tobacco smoke.     

How consumers value healthy houses: a preliminary segmentation of Canadian households

As part of a larger research project which examined the concept of healthy houses in Canada, this study provides a preliminary assessment of potential segments of Canadian householders based on their attitudes about two indoor environmental quality (IEQ) attributes (indoor air quality and lighting). Additionally, concerns about energy efficiency in the home are also addressed. A nationwide survey of households (n = 784) was conducted to search for indications of segments of Canadian householders that value their homes’ indoor environments and energy efficiency, thus addressing issues of consumer interest for healthier homes. Similar groups of householders were derived based on their levels of agreement with a variety of statements regarding some indoor environmental quality attributes and energy efficiency. The specific goals were: (1) to identify segments within Canada which indicate the presence of potential consumers of healthier houses on a broader scale; and (2) to characterize these groups using attitudinal and demographic variables. Segmentation in this study was conducted using a k-means cluster analysis, with the clusters being characterized using demographic and attitudinal information. Results indicated that there is indeed an identifiable segment within the Canadian housing sector for products and services associated with the healthy housing concept. Although housing and policy recommendations are not explicitly made, both private and public stakeholders in the Canadian housing sector could benefit by taking note of these findings.

既有住宅失能老人居室空间光热环境及舒适性评价研究

基于对失能老人居家养老支持性 需求中物理环境需求的考虑,探究我国不同 年代既有住宅失能老人居室空间的光热环 境现状以及舒适性情况。文章以哈尔滨为 例,选取2000年前后建造的失能老人住宅 典型户型3户,对其居室空间的天然光照度、 温度、湿度、风速以及空气品质进行连续实 测,获得居室物理环境现状,分析其天然光 环境、热湿环境、光热环境以及空气质量情 况,并进行舒适性评价,发现其亟待改造的 物理环境因素。研究表明：一、2000年前住 宅居室采光效果差,天然光环境急需改善, 且当室内平均照度低于600 lx时,失能老人开 始普遍认为光环境舒适性降低;二、调研间,2000年后住宅居室室内外平均温度差低于2000年前住宅居室,室内温度与室外温度相关性 较2000年前住宅居室高,室内温度较不稳定,部分时间室内热湿环境情况落在 ASHRAE舒适 区以及夏季实际热舒适区间外,在获得更加稳定舒适的热湿环境方面仍需改进;三、居室空间 的光热环境有一定关联性且受外窗影响,如通过改造外窗提升室内环境质量需考虑光热环境平 衡问题,改造受限时也可通过调整功能布局以适应现有光热环境。本研究将为今后失能老人住 宅适老性环境改造提供更有针对性的研究基础。     

三位一体系统的可行性探讨

阐述了一种由太阳能热水器、普通家用空调热泵、蓄能水箱组成的"三位一体"系统.它充分发挥了三者结合的优势,大大提高了低品位能量的利用效率.风冷和水冷的同时进行,从更高层次上保证了室内的舒适度.组合式室外换热器的运用.提高了风冷的效果:自由流动管的运用减少了夏季风冷时的热污染."三位一体"的灵活运用改善了冬、夏季的热泵运行工况.对节能减排、保护环境有着重要意义.     

Monitoring and modeling of household air quality related to use of different Cookfuels in Paraguay

In Paraguay, 49% of the population depends on biomass (wood and charcoal) for cooking. Residential biomass burning is a major source of fine particulate matter (PM_2.5) and carbon monoxide (CO) in and around the household environment. In July 2016, cross‐sectional household air pollution sampling was conducted in 80 households in rural Paraguay. Time‐integrated samples (24 hours) of PM_2.5 and continuous CO concentrations were measured in kitchens that used wood, charcoal, liquefied petroleum gas (LPG), or electricity to cook. Qualitative and quantitative household‐level variables were captured using questionnaires. The average PM_2.5 concentration (μg/m³) was higher in kitchens that burned wood (741.7 ± 546.4) and charcoal (107.0 ± 68.6) than in kitchens where LPG (52.3 ± 18.9) or electricity (52.0 ± 14.8) was used. Likewise, the average CO concentration (ppm) was higher in kitchens that used wood (19.4 ± 12.6) and charcoal (7.6 ± 6.5) than in those that used LPG (0.5 ± 0.6) or electricity (0.4 ± 0.6). Multivariable linear regression was conducted to generate predictive models for indoor PM_2.5 and CO concentrations (predicted R² = 0.837 and 0.822, respectively). This study provides baseline indoor air quality data for Paraguay and presents a multivariate statistical approach that could be used in future research and intervention programs.     

Home interventions are effective at decreasing indoor nitrogen dioxide concentrations

Nitrogen dioxide (NO₂), a by‐product of combustion produced by indoor gas appliances such as cooking stoves, is associated with respiratory symptoms in those with obstructive airways disease. We conducted a three‐armed randomized trial to evaluate the efficacy of interventions aimed at reducing indoor NO₂ concentrations in homes with unvented gas stoves: (i) replacement of existing gas stove with electric stove; (ii) installation of ventilation hood over existing gas stove; and (iii) placement of air purifiers with high‐efficiency particulate air (HEPA) and carbon filters. Home inspection and NO₂ monitoring were conducted at 1 week pre‐intervention and at 1 week and 3 months post‐intervention. Stove replacement resulted in a 51% and 42% decrease in median NO₂ concentration at 3 months of follow‐up in the kitchen and bedroom, respectively (P = 0.01, P = 0.01); air purifier placement resulted in an immediate decrease in median NO₂ concentration in the kitchen (27%, P < 0.01) and bedroom (22%, P = 0.02), but at 3 months, a significant reduction was seen only in the kitchen (20%, P = 0.05). NO₂ concentrations in the kitchen and bedroom did not significantly change following ventilation hood installation. Replacing unvented gas stoves with electric stoves or placement of air purifiers with HEPA and carbon filters can decrease indoor NO₂ concentrations in urban homes.     

住宅采暖能耗与住户调节行为关系的分析研究

本文以北京市2栋满足"第三步"建筑节能设计标准并安装分户热计量装置的新建住宅楼为研究对象,对楼内的115个住户进行冬季采暖耗热量等相关数据的逐周采集,并对其中8个住户的房间进行室温连续测试。调查和测试结果表明:住户房间室内的热舒适度明显提高,但按照室内、外设计参数折算后的采暖耗热量仍超过"第三步"建筑节能设计标准所要求的限值。导致该现象的主要原因在于住户调节行为方式所决定的房间通风状况、室温设定偏高及邻室传热等因素的影响。     

A comparative study of human exposures to household air pollution from commonly used cookstoves in Sri Lanka

Solid fuel burning cookstoves are a major source of household air pollution (HAP) and a significant environmental health risk in Sri Lanka. We report results of the first field study in Sri Lanka to include direct measurements of both real‐time indoor concentrations and personal exposures of fine particulate matter (PM_2.5) in households using the two most common stove types in Sri Lanka. A purposive sample of 53 households was selected in the rural community of Kopiwatta in central Sri Lanka, roughly balanced for stove type (traditional or improved ‘Anagi’) and ventilation (chimney present or absent). At each household, 48‐h continuous real‐time measurements of indoor kitchen PM_2.5 and personal (primary cook) PM_2.5 concentrations were measured using the RTI MicroPEM^? personal exposure monitor. Questionnaires were used to collect data related to household demographics, characteristics, and self‐reported health symptoms. All primary cooks were female and of an average age of 47 years, with 66% having completed primary education. Median income was slightly over half the national median monthly income. Use of Anagi stoves was positively associated with a higher education level of the primary cook (P = 0.026), although not associated with household income (P = 0.18). The MicroPEM monitors were well‐received by participants, and this study's valid data capture rate exceeded 97%. Participant wearing compliance during waking hours was on average 87.2% on Day 1 and 83.3% on Day 2. Periods of non‐compliance occurred solely during non‐cooking times. The measured median 48‐h average indoor PM_2.5 concentration for households with Anagi stoves was 64 μg/m³ if a chimney was present and 181 μg/m³ if not. For households using traditional stoves, these values were 70 μg/m³ if a chimney was present and 371 μg/m³ if not. Overall, measured indoor PM_2.5 concentrations ranged from a minimum of 33 μg/m³ to a maximum of 940 μg/m³, while personal exposure concentrations ranged from 34 to 522 μg/m³. Linear mixed effects modeling of the dependence of indoor concentrations on stove type and presence or absence of chimney showed a significant chimney effect (65% reduction; P < 0.001) and an almost significant stove effect (24% reduction; P = 0.054). Primary cooks in households without chimneys were exposed to substantially higher levels of HAP than those in households with chimneys, while exposures in households with traditional stoves were moderately higher than those with improved Anagi stoves. As expected, simultaneously measuring both indoor concentrations and personal exposure levels indicate significant exposure misclassification bias will likely result from the use of a stationary monitor as a proxy for personal exposure. While personal exposure monitoring is more complex and expensive than deploying simple stationary devices, the value an active personal PM monitor like the MicroPEM adds to an exposure study should be considered in future study designs.     

Household biomass fuel use is associated with chronic childhood malnutrition: Result from a nationwide cross-sectional survey in Bangladesh

Despite significant investment, childhood malnutrition continues to be a significant public health problem especially in least developed countries. The aim of this study was to find association between household biomass fuel (BMF) use and childhood malnutrition in Bangladesh using data from Demographic and Health Survey 2011. We included a total 6891 children under 5 years of age in the analysis. The prevalence of wasting, underweight, and stunting from BMF using household was 16.1% (n = 997; 95%CI, 15.1–17.3), 39.0% (n = 2399; 95%CI, 37.1–40.9), and 43.3% (n = 2620; 95%CI, 41.6–45.1), respectively. Underweight and stunting were significantly higher among children from households using BMF compared with the children from CF using households (underweight, biomass vs clean fuel: 39.0% vs. 23.5%, p < 0.001; stunting, biomass vs clean fuel: 43.3 vs. 31.5%, p < 0.001). The use of BMF in the household was significantly associated with underweight (OR = 1.38; 95%CI: 1.10–1.73) and stunting (OR = 1.58; 95%CI: 1.18–1.98) among children <5 years of age after adjusting possible confounders in mixed effect logistic regression analysis. This study found a significant association between chronic childhood malnutrition and household BMF use which is indicating possible alternative risk factor for malnutrition. Further prospective research is required to explore the mechanism of how BMF use results in chronic malnutrition.     

Factors controlling volatile organic compounds in dwellings in Melbourne,Australia

This study characterized indoor volatile organic compounds (VOCs) and investigated the effects of the dwelling characteristics, building materials, occupant activities, and environmental conditions on indoor VOC concentrations in 40 dwellings located in Melbourne, Australia, in 2008 and 2009. A total of 97 VOCs were identified. Nine VOCs, n‐butane, 2‐methylbutane, toluene, formaldehyde, acetaldehyde, d‐limonene, ethanol, 2‐propanol, and acetic acid, accounted for 68% of the sum of all VOCs. The median indoor concentrations of all VOCs were greater than those measured outdoors. The occupant density was positively associated with indoor VOC concentrations via occupant activities, including respiration and combustion. Terpenes were associated with the use of household cleaning and laundry products. A petroleum‐like indoor VOC signature of alkanes and aromatics was associated with the proximity of major roads. The indoor VOC concentrations were negatively correlated (P < 0.05) with ventilation. Levels of VOCs in these Australian dwellings were lower than those from previous studies in North America and Europe, probably due to a combination of an ongoing temporal decrease in indoor VOC concentrations and the leakier nature of Australian dwellings.     

Microbiological consequences of indoor composting

Recycling of organic waste appeals to more and more people. The aim of this study was to evaluate the microbiological contamination around organic waste bins at three distances over a 12‐month period. Contamination near the customary trash of control households was evaluated at the beginning to ensure that there is no recruitment bias. Air samples using the MAS 100 impactor were carried out in 38 dwellings that do household waste composting and in 10 dwellings of controls. Collection of particles by CIP 10 rotating cup sampler and dust samples collected by electrostatic dust collector cloths were acquired in dwellings that do household waste composting. Samples were analyzed by culture and by real‐time quantitative PCR. Information about dwelling characteristics and inhabitant practices was obtained by a standardized questionnaire. The genera most often isolated were Penicillium, Aspergillus, Cladosporium and Streptomyces. Near the organic waste bins, bioaerosol samples showed an increase of Acarus siro (P = 0.001). Sedimented dust analyses highlighted an increase of A. siro, Wallemia sebi, Aspergillus versicolor, and Cladosporium sphaerospermum concentrations after a 12‐month survey compared to the beginning. Composting favors microorganism development over time, but does not seem to have an effect on the bioaerosol levels and the surface microbiota beyond 0.5 m from the waste bin.     

Kerosene lighting contributes to household air pollution in rural Uganda

The literature on the contribution of kerosene lighting to indoor air particulate concentrations is sparse. In rural Uganda, kitchens are almost universally located outside the main home, and kerosene is often used for lighting. In this study, we obtained longitudinal measures of particulate matter 2.5 microns or smaller in size (PM_2.5) from living rooms and kitchens of 88 households in rural Uganda. Linear mixed‐effects models with a random intercept for household were used to test the hypotheses that primary reported lighting source and kitchen location (indoor vs outdoor) are associated with PM_2.5 levels. During initial testing, households reported using the following sources of lighting: open‐wick kerosene (19.3%), hurricane kerosene (45.5%), battery‐powered (33.0%), and solar (1.1%) lamps. During follow‐up testing, these proportions changed to 29.5%, 35.2%, 18.2%, and 9.1%, respectively. Average ambient, living room, and kitchen PM_2.5 levels were 20.2, 35.2, and 270.0 μg/m³. Living rooms using open‐wick kerosene lamps had the highest PM_2.5 levels (55.3 μg/m³) compared to those using solar lighting (19.4 μg/m³; open wick vs solar, P=.01); 27.6% of homes using open‐wick kerosene lamps met World Health Organization indoor air quality standards compared to 75.0% in homes using solar lighting.     

Methods for quantifying Staphylococcus aureus in indoor air

Staphylococcus aureus has been detected in indoor air and linked to human infection. Quantifying S. aureus by efficient sampling methods followed by appropriate sample storage treatments is essential to characterize the exposure risk of humans. This laboratory study evaluated the effects of sampler type (all‐glass impinger (AGI‐30), BioSampler, and Andersen one‐stage sampler (Andersen 1‐STG)), collection fluid (deionized water (DW), phosphate‐buffered saline (PBS), and Tween mixture (TM)), and sampling time (3–60 min) on cell recovery. Effects of storage settings on bacterial concentration were also assessed over 48 h. Results showed BioSampler performed better than Andersen 1‐STG and AGI‐30 (P < 0.05) and TM was superior to PBS and DW (P < 0.05). An increase in sampling time negatively affected the recoveries of cells in PBS of BioSampler and AGI‐30 (P < 0.05), whereas cell recoveries in TM were increased at sampling of 6–15 min compared with 3 min. Concentrations of cells collected in PBS were decreased with storage time at 4 and 23°C (P < 0.05), while cells stored in TM showed stable concentrations at 4°C (P > 0.05) and increased cell counts at 23°C (P < 0.05). Overall, sampling by BioSampler with TM followed by sample transportation and storage at 4°C is recommended.     

Exhaust ventilation in attached garages improves residential indoor air quality

Previous research has shown that indoor benzene levels in homes with attached garages are higher than homes without attached garages. Exhaust ventilation in attached garages is one possible intervention to reduce these concentrations. To evaluate the effectiveness of this intervention, a randomized crossover study was conducted in 33 Ottawa homes in winter 2014. VOCs including benzene, toluene, ethylbenzene, and xylenes, nitrogen dioxide, carbon monoxide, and air exchange rates were measured over four 48‐hour periods when a garage exhaust fan was turned on or off. A blower door test conducted in each garage was used to determine the required exhaust fan flow rate to provide a depressurization of 5 Pa in each garage relative to the home. When corrected for ambient concentrations, the fan decreased geometric mean indoor benzene concentrations from 1.04 to 0.40 μg/m³, or by 62% (P<.05). The garage exhaust fan also significantly reduced outdoor‐corrected geometric mean indoor concentrations of other pollutants, including toluene (53%), ethylbenzene (47%), m,p‐xylene (45%), o‐xylene (43%), and carbon monoxide (23%) (P<.05) while having no impact on the home air exchange rate. This study provides evidence that mechanical exhaust ventilation in attached garages can reduce indoor concentrations of pollutants originating from within attached garages.     

Field performance measurements of a heat pump desiccant unit in dehumidification mode

The variable refrigerant volume (VRV) air conditioning system needs to be operated in conjunction with a ventilation system, because the VRV system cannot provide any fresh air. The common ventilation unit used with the VRV system is the heat recovery ventilation (HRV) unit. In this study, a new ventilation unit, a self-regenerating heat pump desiccant (HPD) unit, was introduced and the characteristics of the HPD unit was experimentally investigated over a wide range of operating conditions in a field performance test. In addition, the energy saving contribution of the HPD and HRV units to the VRV system was compared. It was found that the HPD unit maintained the target indoor humidity ratio of 10 g/kg throughout the cooling season resulting in a better indoor thermal comfort than the HRV unit. Besides, it was found that the outdoor unit of the VRV system consumed 26.3% less energy for the operation in conjunction with the HPD unit as compared to the operation in conjunction with the HRV unit.