Reduce Indoor Air Pollution Research Articles

How can interventions of building renovation and household energy conversion effectively improve the physical and mental health outcomes? A systematic review and meta-analysis

Household energy efficiency measures can effectively reduce indoor air pollution and positively impact the health of residents, but there is no conclusive evidence on the effectiveness of different energy efficiency measures for various diseases. This study used systematic review and meta-analysis to research the effects of two interventions on residents’ physical and mental health: building renovation (heating, insulation, double-glazed windows and ventilation) and household energy conversion (stove upgrading and clean energy use). A total of 79 papers published between 1977 and 2023 were reviewed in this study, providing comprehensive meta-analytic evidence on the effectiveness of energy efficiency measures. The results show that household energy-saving measures have a minor but significant positive influence on residents’ physical and mental health, with the effect on mental health being larger than the impact on physical health. Stove upgrading is advantageous in respiratory and cardiovascular diseases; insulation can greatly reduce the risk of skin diseases; heating is beneficial in sensory and digestive diseases; and clean energy use can successfully mitigate integrative diseases. Furthermore, a combination of heating and insulation measures has the most favourable influence on mental health conditions such as depression, anxiety and social isolation. The study findings can help residents, policymakers and relevant organizations take appropriate interventions to promote residents’ physical and mental health.

Assessment of Indoor Air Quality and Influential Factors: A Study in Rural Areas of Solan District, Himachal Pradesh (India)

The study was conducted during December, 2020 to June, 2021 to assess indoor air quality (IAQ) and develop amelioration strategies in rural areas of the Solan district, located in Himachal Pradesh, India. A well-structured pre-tested questionnaire was used to assess the factors responsible for indoor air quality.The indoor air quality parameters including PM10, Non-Respirable Suspended Particulate Matter (NRSPM), Total Suspended Particulate Matter (TSPM), Nitrogen dioxide (NO2) and Sulfur dioxide (SO2)were studied to calculate air quality index.The findings revealed substantial variation in pollution levels among different villages. Nauni village had the highest concentration of pollutants, with PM10 levels at 24.17 µg m3-1, NRSPM at 20.37 µg m3-1, TSPM at 44.54 µg m3-1, NO2 at 12.54 µg m3-1 and SO2 at 0.35 µg m3-1. In contrast, Nagali village has the lowest levels of these contaminants. Despite variations, all recorded values were within permissible limits. Nine factors were identified as contributing to poor indoor air quality: fuel wood-based cooking, smoke sources, mode of ventilation, insect/pest control measures, waste disposal near the house, use of perfumes and air freshners, cowshed near the house, intermittent cleaning, and dampness in the house due to leakage. To reduce indoor air pollution in rural areas, the study suggests establishing concentrated methods that address these specific issues. Proper ventilation, alternate cooking methods and better waste management procedures are important steps in improving indoor air quality and protecting public health.

Unseen crisis: Revealing the hidden health impact of indoor air pollution—A scoping review

Indoor air pollution presents a critical public health challenge, particularly in countries such as India, where millions are exposed to harmful pollutants within their homes and workplaces. This scoping review delves into the multifaceted impacts of indoor air pollution on health outcomes, synthesizing evidence from various study designs and geographical regions A scoping review was conducted. Drawing on a comprehensive search strategy, which yielded 320 records, wherein 120 in PubMed, 108 in Web of Science, and 92 in SCOPUS. Ten studies were selected based on predefined inclusion criteria, totaling a sample size of 37,43166 individuals. The synthesis of findings from the selected studies reveals the multifaceted impact of indoor air pollution on health status. Respiratory symptoms and illnesses were found to be prevalent among individuals exposed to indoor pollutants, with biomass fuel combustion posing a particularly high risk for chronic obstructive pulmonary disease (COPD) in women. In addition, indoor air pollution was associated with adverse pregnancy outcomes, cardiovascular diseases, central nervous system impacts, cognitive impairment, and developmental delays. Urgent action is needed to reduce indoor air pollution, safeguard health, and promote cleaner technologies for healthier indoor environments. Vulnerable populations, such as women, children, and the elderly, are disproportionately affected by indoor pollutants, highlighting the importance of targeted interventions and policies.

Hierarchical three-layered fibers for bioaerosol and CO2 capture, and antimicrobial performance

As the duration of indoor activities has increased owing to environmental issues and the prevalence of respiratory diseases, it has become important to reduce indoor air pollutants. In this study, air filters with structurally modified surfaces are fabricated to effectively capture and remove indoor air pollutants. High-temperature alkali treatment is applied to a smooth fiber filter to convert it into porous calcium silicate hydrate and create a hierarchical three-layered (H3L) fibrous structure. The outer, middle, and inner layers of the H3L fiber are designed for bioaerosol capture and disinfection, CO2 capture, and maintenance of mechanical strength, respectively. An antimicrobial agent ((3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride, TPMMC) is covalently grafted onto the surface of H3L fibers to impart antimicrobial performance. The H3L-TPMMC filter outperforms the bare filter in capturing E. coli and S. aureus aerosols, displaying improved quality factors of 31.9 % and 63.9 %, respectively. It achieves a 99.999 % reduction and 99.790 % for the collected E. coli and S. aureus aerosols, respectively. The H3L-TPMMC filter demonstrates selective CO2 capture and maintains consistent performance and antimicrobial efficacy even in environments with bioaerosols and CO2. This hierarchical filter membrane provides an efficient approach for reducing various indoor air pollutants using a single filter system.

Advancing Methodologies for Investigating PM2.5 Removal Using Green Wall System.

Combustion processes are the primary source of fine particulate matter in indoor air. Since the 1970s, plants have been extensively studied for their potential to reduce indoor air pollution. Leaves can retain particles on their surfaces, influenced by factors such as wax content and the presence of hairs. This study introduces an innovative experimental approach using metal oxide particles in an office-like environment to evaluate the depolluting effect of plant walls. Two plant walls were installed in a controlled room, housing three plant species: Aglaonema commutatum 'Silver Bay', Dracaena fragrans, and Epipremnum aureum. Metal oxide particles were introduced via a compressed air blower positioned between the two walls. The concentration of these particles was monitored using PM2.5 sensors, and the deposition of iron (Fe) on the leaves was quantified through Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This novel methodology effectively demonstrated the utility of both real-time sensors and ICP-MS in quantifying airborne particle concentrations and leaf deposition, respectively. The results revealed that Dracaena fragrans had a 44% higher Fe particle retention rate compared to the control (wallpaper). However, further validation through methodological replication is necessary to confirm the reproducibility of these findings.

IOT-Based Air Purifier with Quality Monitoring .

The aim of this project is to develop an intelligent air purifier with quality monitoring capabilities to reduce indoor air pollution and mitigate health risks. With indoor air quality becoming a growing concern, especially in densely populated areas like India where a significant portion of the population is engaged in agriculture, there is a pressing need for innovative solutions. The "Design and Fabrication of Smart Air Purifier with Quality Monitoring" system is designed to address this need by minimizing indoor air pollution while enhancing monitoring accuracy and efficiency. The proposed system features a multipurpose autonomous air purifier equipped with quality monitoring sensors, controlled via an ESP module. Field tests demonstrate the system's successful operation, with the air purifier effectively removing pollutants while monitoring air quality parameters in real-time. Keywords: Smart Air Purifier, Quality Monitoring, ESP-Module, Indoor Air Pollution

Valuing Interventions to Reduce Indoor Air Pollution— Fuelwood, Deforestation, and Health in Rural Nepal

Household energy use, forest and poverty are entangled in developing countries with environmental and health problems. Dependence on wood for cooking fuel generally increases the dependency of poor people on forests. This fuelwood consumption is not only linked to the forest environment, but also to the health of the inhabitants due to indoor air pollution. As the women are exposed more to the smoke pollution than the men, and children are more sensitive to it than adults, the issue of fuel is also linked with the gender and child issues. Fuelwood is the main source of cooking energy in Nepal and will remain so for foreseeable future. About 66 percent of households use wood as the main fuel for cooking. Only about 13 and eight percent households, mostly in urban areas, use kerosene and LPG respectively. The households using biogas as the main fuel is less than two percent [CBS (2002)]. One study shows that over 89 percent of total energy use in Nepal comes from the traditional fuels [ADB (2003)]. Wood and other biomass fuels (crop residues as well as animal dung) can substitute for each other, though most consumers have a general preference for wood over other biomass [FAO (1997)]. With socio-economic development, the fuel used by a household changes to better ones in the fuel-ladder. Everybody likes to maximise their utility by choosing more convenient and prestigious fuel subject to the budget constraint. Climbing the fuel-ladder generally means stepping up from dung cakes or crop residues, fuelwood, kerosene, biogas, LPG and ultimately to the electricity. Moving to the higher steps in the ladder means better respiratory health of the family members due to lower emission.

Reducing Indoor Air Pollution through Personalized Ventilation for Occupants in Office Environments and Confined Spaces

With the increasing focus on indoor environmental quality, driven by the growing amount of time people spend in enclosed spaces, this study presents an approach to enhancing air distribution in office environments and confined spaces. A novel low-induction air diffuser is designed to deliver fresh, clean air in close proximity to occupants while maintaining their thermal comfort. Clean, unpolluted air is pivotal to healthy and productive workplaces. Yet, this paper underscores the importance of not sacrificing thermal comfort in the pursuit of improved indoor air quality. Inadequate thermal comfort may lead occupants to deactivate ventilation systems, negating the benefits of improved air quality. Inefficient temperature control can also result in discomfort, distractions, and reduced productivity. The innovative low-induction air diffuser resolves this issue, enhancing air quality near occupants without causing thermal discomfort. By directing air gently and efficiently, this solution is prepared to transform personalized ventilation systems, mitigating the discomfort associated with traditional jet flows while delivering high-quality breathable air. This research serves as a bridge between improved indoor air quality and thermal comfort, for office environments. It introduces a practical, energy-efficient solution that satisfies the core requirements of a healthy workspace—clean air and comfortable conditions.

Experimental Investigation and Performance Evaluation of Jatropha Oil-Biodiesel Blending with Kerosene for Domestic Cooking and Lighting Applications.

Reducing indoor air pollution and the related costs requires developing efficient cooking and lighting technologies as well as alternative energy sources. The appropriateness of virgin jatropha (Jatropha curcas) oil, its biodiesel, and the blending of these fuels with kerosene for wick stove lighting and cooking was examined in this study. To describe the fuel performance, a range of blending ratios were examined and characterizations were made of the fuel's density, calorific value, boiling point, viscosity, and rate of fuel consumption. To assess the fuels' thermal degradation behaviors, thermogravimetric and water boiling tests were performed. An air pollution meter was used to describe the levels of indoor air pollution. According to the findings, the virgin oil from Jatropha has a kinematic viscosity of 30.1 mm2/s. The 50% jatropha oil and 80% biodiesel blended with kerosene showed a reduction in viscosity of 72.6% and 46.8%, respectively. The thermal efficiency of the virgin oil, its biodiesel, and blending of these fuels with kerosene was in the range of 10-48%. Complete degradation of jatropha oil, its biodiesel, and 40 : 60 ratio of jatropha biodiesel and kerosene blend was conducted in the temperature range of 480-700 k, 185-280.6 K, and 100-300 K, respectively. The activation energies of jatropha oil, biodiesel, and kerosene blend (40 : 60) were 191.3, 73, and 25 kJ/mol, respectively. The average concentrations of particulate matter and carbon monoxide for pure jatropha oil biodiesel were 209.71 µg/m3 and 5.5 mg/kg, respectively. Thus, jatropha biodiesel and its blending with kerosene are suitable fuels for cooking and lighting operations in rural communities who are living far from the electrical grid compared with virgin oil fuel.

Women's Participation in Dairy Livestock Farming in Pokhara

This study examines contribution of women participation in dairy livestock farming in Pokhara. For this, two objectives, to assess the integration between dairy livestock enterprise and crop production and to examine the dairy livestock farming income and household food in-security were set.As a commuter zone ward number 5, 18 and 23 of Pokhara Metropolitan City was purposively taken as research area. Those people who were actively engaged in milk business and contributing whole family income and expenditure were purposively taken as universe of this research. Out of those universe, 60 household of women actively engaging in milk business were taken as research sample. Study clearly shows the financial gain to the family from milk business. The saving from milk business itself can pay back initial livestock purchasing investment within a single year. In viewed through the gender prospects livestock farming supports married women in participation on community organization and strengthen the role of women in decision making as a social agent. This business not only engages married women in milk business but also helped to increase the productivity of crops by using cattle manure. Additionally, use of cattle faces in biogas has reduced the fuel wood and fossil fuel consumption and supports sustainable development by providing clean energy together with forest conservation and reduced indoor air pollution. The policies addressing the availability of good source of fodder, business startup fund facilitation, a sustainable market to sell milk, good insurance policy and adoption of cutting-edge technologies can attract young and educated people in the milk business.

Enhancing indoor air quality and sustainable living in newly constructed apartments: insights from Dubai

This research paper examines Indoor Air Quality (IAQ) conditions in newly constructed apartments in Dubai to be more sustainable for residents to have healthier lifestyles. Enhanced airtightness and chemical-laden materials contribute to IAQ pollution in these buildings. The study aims to assess pollutant concentrations and variations based on building height. Measurements were conducted in 12 apartment units using the WHO’s IAQ assessment methodology. Most pollutants were within limits, but TVOC exceeded the Dubai Municipality’s standard, measuring at 2634.4 μg/m³, approximately nine times higher than the standard. HCHO (163.4 μg/m³) and toluene (551.4 μg/m³) were identified as significant pollutants with potential health effects. Analysis of pollutant concentrations based on building height revealed higher TVOC levels in upper areas, with 2,828 μg/m³ in the upper area compared to 2,443 μg/m³ in the lower area, indicating more severe indoor air pollution in Ethylbenzene and styrene also highest in upper areas, with ethylbenzene at 122 μg/m³ and styrene at 82 μg/m³ in the upper area, potentially due to elevated sources. Toluene and xylene concentrations were elevated in the middle area, with toluene at 574 μg/m³ and xylene at 321 μg/m³, likely influenced by materials and occupant activities. Benzene concentrations were consistent across all heights at 2.94 μg/m³, suggesting a common source. HCHO concentrations were relatively consistent but slightly higher in the middle and upper areas, with 171 μg/m³ in both, likely influenced by ventilation and emissions. While average pollutant concentrations met WHO standards, many units exceeded recommended limits, requiring targeted interventions. The study highlights the importance of addressing IAQ concerns and implementing strategies to reduce indoor air pollutants and improve ventilation. These findings contribute to IAQ knowledge in Dubai’s residential buildings, guiding policymakers, architects, and developers in effective policies and guidelines. Further research on seasonal variations and other IAQ factors is recommended for better understanding and long-term monitoring. Prioritizing IAQ in newly constructed apartments is crucial for healthier living in Dubai. The residential building sector can protect residents’ health by implementing appropriate measures while delivering upscale living experiences.

Some features of air pollution monitoring as a component of the microclimate of the premises

The quality of living space largely depends on the quality of indoor air. The physical and chemical properties of the air people breathe can affect their health and comfort. Indoor air pollution in residential and workplace environments can occur due to various activities of occupants or employees, such as cooking, smoking, and using electronic devices, as well as emissions of pollutants from building materials and the use of certain products. Pollutants that can be present indoors include carbon monoxide, formaldehyde, volatile organic compounds, particulate matter, aerosols, biological contaminants, and more. To effectively monitor the quality of atmospheric air, it is necessary to determine the main sources of air pollution, which is the purpose of this study. Naturally, the quality of indoor air cannot be clearly separated from the ambient air quality. The first factor affecting the microclimate is the level of air pollution near the building. Air from the street enters the room through windows, doors, or the building's ventilation system. If the state of the surrounding environment is unfavorable, the concentration of harmful substances indoors may also exceed the norm. However, indoor sources of air pollution in any building can have a much greater impact on the health and comfort of the people inside it. Materials used in construction, such as concrete or mineral insulation, may contain ammonia, formaldehyde, and other substances that are released from building structures over time and deteriorate indoor air quality. Ensuring control and monitoring of indoor air quality is an extremely important task. This includes measuring concentrations of pollutants and identifying their sources. It is also important to adhere to standards and recommendations developed by health and environmental organizations to ensure safety and comfort indoors. To reduce indoor air pollution, various measures can be implemented, such as selecting appropriate building materials, and ventilation, installing purification systems, controlling sources of pollution, and limiting the impact of human activity. Keywords: air pollution, microclimate parameters, air quality monitoring, harmful substances.

Production and characterization of ecological fire starter from sawdust and vegetable oil

The objective of this article aims to reduce indoor air pollution through the use of ecological fire starter (EFS) made from sawdust and vegetable oils. In the Far North region of Cameroon, plastic waste is used to ignite and stoke solid fuels fires, exposing mainly women and children who are responsible for cooking to health risks from indoor air pollution. Thus, the survey conducted among the population of the region shows that 96% of urban households use plastics waste made with LDPE, HDPE, PET, PS, PP and EVA as fire starter for solid fuels. In the region, 5544 tons of plastic used by households could emit approximately 15,314 tons of CO2 eq per year. The region has a manufacturing capacity of 1000 tons of EFS while its need is 894 tons in 2022. The lower heating value of the EFS varies between 31.914 ± 0.810 and 25.127 ± 0.026 MJ/kg, and have many ecological health and economic advantages. A household needs about 10 g of EFS to ignite solid fuel per day, with an annual expenditure ranging from 5.5 and US$ 7 to purchase EFS. Therefore, it is important to promote EFS through developing countries and look for another way to recover plastic waste.

Bioenergy and nutrition: Positive linkages for the achievement of the UN Sustainable Development Goals

AbstractBioenergy and nutrition represent two key elements in maintaining health and well‐being. Bioenergy is a form of renewable energy produced from organic materials, which can be used for generating power, while nutrition, on the other hand, is related to the ability of food to provide the proper nutrients to living beings and the factors that make up a healthy diet. The 2030 Sustainable Development Agenda has brought considerable attention to the importance of food security and nutrition, particularly under SDG2, while concurrently highlighting the need to ensure affordable, reliable, sustainable, and modern energy access for all under SDG7. The accomplishment of these two Goals is crucial for almost all others, as they are closely interconnected with many cross‐cutting elements and commonly framed in the Water Energy Food Nexus. In this context, modern bioenergy has the potential to aid in the accomplishment of the SDGs, when value chains and conversion processes are designed and managed in an appropriate and sustainable manner. Nevertheless, the positive relationship between bioenergy and nutrition is an overlooked nexus, whose analysis has been too often limited to the competition for resources, such as land, water, energy, and other inputs. Considering this, the present review was developed for both the nutrition and bioenergy communities to begin to overcome the limits of the food versus fuel paradigm, by analyzing this intricate nexus and bringing to light interlinkages and potential synergies existing between bioenergy and nutrition. So far, such linkages appear indirect or implied, therefore further research in this area would be beneficial. The strongest links between bioenergy and nutrition identified include: greater cooking efficiency, reduced indoor air pollution, and improved environmental sanitation through bioenergy clean cooking solutions; energy access for transporting, storing, and cooking food, thus reducing food loss and waste and diversifying diets; improved soil fertility through Carbon Capture and Storage (CCS), phytoremediation, and integrated biomass production systems; and better rural livelihoods and increased income by introducing bioenergy production and use as a circular economy practice. The major significance of this review is the identification of examples of good practices applied along the different stages of the bioenergy value chain with potential co‐benefits for nutrition. In this way, this work aims to provide preliminary findings for researchers to better determine the ways in which bioenergy can be deployed to improve global nutrition.This article is categorized under: Sustainable Energy > Bioenergy Sustainable Development > Goals Sustainable Development > Energy‐Water‐Food Nexus

A modular systematic review of antenatal interventions targeting modifiable environmental exposures in improving low birth weight

BackgroundLow birth weight (LBW) increases the risk of short- and long-term morbidity and mortality from early life to adulthood. Despite research effort to improve birth outcomes the progress has been slow. ObjectiveThis systematic search and review of English language scientific literature on clinical trials aimed to compare the efficacy antenatal interventions to reduce environmental exposures including a reduction of toxins exposure, and improving sanitation, hygiene, and health-seeking behaviors, which target pregnant women to improve birth outcomes. MethodsWe performed eight systematic searches in MEDLINE (OvidSP), Embase (OvidSP), Cochrane Database of Systematic Reviews (Wiley Cochrane Library), Cochrane Central Register of Controlled Trials (Wiley Cochrane Library), CINAHL Complete (EbscoHOST) between 17 March 2020 and 26 May 2020. ResultsFour documents identified describe interventions to reduce indoor air pollution: two randomised controlled trials (RCTs), one systematic review and meta-analysis (SRMA) on preventative antihelminth treatment and one RCT on antenatal counselling against unnecessary caesarean section. Based on the published literature, interventions to reduce indoor air pollution (LBW: RR: 0.90 [0.56, 1.44], PTB: OR: 2.37 [1.11, 5.07]) or preventative antihelminth treatment (LBW: RR: 1.00 [0.79, 1.27], PTB: RR: 0.88 [0.43, 1.78]) are not likely to reduce the risk of LBW or Preterm birth (PTB). Data is insufficient on antenatal counselling against caesarian-sections. For other interventions, there is lack of published research data from RCTs. ConclusionsWe conclude that there is a paucity of evidence from RCT on interventions that modify environmental risk factors during pregnancy to potentially improve birth outcomes. Magic bullets approach might not work and that it would be important to study the effect of the broader interventions, particularly in LMIC settings. Global interdisciplinary action to reduce harmful environmental exposures, is likely to help to reach global targets for LBW reduction and sustainably improve long-term population health.

Determinants of pneumonia among under-five children in Oromia region, Ethiopia: unmatched case-control study

BackgroundPneumonia is the single largest infectious disease that causes more under-five morbidity and mortality than any other infectious disease in the world, including Ethiopia. The aim of this study is to assess determinants of pneumonia among under-five children in the South West Shewa Zone, Oromia Region, Ethiopia, 2021.MethodsWe used an unmatched case-control study design from March 15 to April 30, 2021, in the South West Shewa Zone, Ethiopia. A sample of 398 (199 cases and 199 controls) participated in the study. Trained data collectors through a pre-tested structured questionnaire collected data. We used Epi Info to enter data and analyzed using SPSS version 23. We described our data using descriptive statistics. We identified predictors of pneumonia using logistic regression analysis. We declared predictors of pneumonia at a P-value of 0.05 or less.ResultsBreastfeeding for less than 6 months [AOR:3.51, 95%CI:(1.12,11.00)], lack of Vitamin A supplementation [AOR:3.56,95%CI:(1.58, 8.05)], history of URTI [AOR:9.66, 95%CI:(4.69,19.87)], family child care practices [AOR:6.46, 95%CI, (2.83,14.76)], sleeping with three to five persons in a room [AOR:2.90, 9%CI: (1.23,6.84)], having above five persons in a room [AOR: 3.88, 95%CI: 1.02,14.77), use of wood as a source of fuel [AOR = 3.02 95% CI: 1.41,6.46)] and not opening windows [AOR:2.56 95%CI: (1.21,5.41)] were independent factors of pneumonia among under five children.ConclusionPneumonia is associated with breastfeeding for less than 6 months, lack of vitamin A supplementation, history of URTI, types of childcare practice, indoor overcrowding, use of wood as a source of fuel, and not opening windows. Therefore, exclusive breastfeeding, improving vitamin A supplementation, early control of respiratory tract infection through promoting good hygiene and ventilation strategies in crowded homes, and promoting how to reduce indoor air pollution through affordable clean stoves will be relevant interventions to reduce under-five pneumonia.

A systematic review on mitigation of common indoor air pollutants using plant-based methods: a phytoremediation approach.

Environmental pollution, especially indoor air pollution, has become a global issue and affects nearly all domains of life. Being both natural and anthropogenic substances, indoor air pollutants lead to the deterioration of the ecosystem and have a negative impact on human health. Cost-effective plant-based approaches can help to improve indoor air quality (IAQ), regulate temperature, and protect humans from potential health risks. Thus, in this review, we have highlighted the common indoor air pollutants and their mitigation through plant-based approaches. Potted plants, green walls, and their combination with bio-filtration are such emerging approaches that can efficiently purify the indoor air. Moreover, we have discussed the pathways or mechanisms of phytoremediation, which involve the aerial parts of the plants (phyllosphere), growth media, and roots along with their associated microorganisms (rhizosphere). In conclusion, plants and their associated microbial communities can be key solutions for reducing indoorair pollution. However, there is a dire need to explore advanced omics technologies to get in-depth knowledge of the molecular mechanisms associated with plant-based reduction of indoor air pollutants.

Effects of indoor air purification intervention on blood pressure, blood‑oxygen saturation, and heart rate variability: A double-blinded cross-over randomized controlled trial of healthy young adults

The use of indoor air purifier (IAP) has received growing attention as a mitigation strategy for reducing indoor air pollution, but the evidence on their cardiovascular benefits is unclear. This study aims to evaluate whether the use of IAP can reduce the adverse effects of indoor particulate matter (PM) on cardiovascular health among young healthy population. A randomized, double-blind, cross-over, IAP intervention of 38 college students was conducted. The participants were assigned into two groups to receive the true and sham IAPs for 36 h in random order. Systolic and diastolic blood pressure (SBP; DBP), blood oxygen saturation (SpO2), heart rate variability (HRV) and indoor size-fractioned particulate matter (PM) were real-time monitored throughout the intervention. We found that IAP could reduce indoor PM by 41.7–50.5 %. Using IAP was significantly associated with a reduction of 2.96 mmHg (95 % CI: −5.71, −0.20) in SBP. Increased PM was significantly associated with increased SBP (e.g., 2.17 mmHg [0.53, 3.81], 1.73 mmHg [0.32, 3.14] and 1.51 mmHg [0.28, 2.75] for an IQR increment of PM1 [16.7 μg/m3], PM2.5 [20.6 μg/m3] and PM10 [37.9 μg/m3] at lag 0–2 h, respectively) and decreased SpO2 (−0.44 % [−0.57, −0.29], −0.41 % [−0.53, −0.30] and − 0.40 % [−0.51, −0.30] for PM1, PM2.5 and PM10 at lag 0–1 h, respectively), which could last for about 2 h. Using IAPs could halve indoor PM levels, even in relatively low air pollution settings. The exposure-response relationships suggested that the benefits of IAPs on BP may only be observed when indoor PM exposure is reduced to a certain level.

Principal stratification analysis to determine health benefit of indoor air pollution reduction in a randomized environmental intervention in COPD: Results from the CLEAN AIR study

BackgroundIndoor air quality represents a modifiable exposure to Chronic Obstructive Pulmonary Disease (COPD) health. In a randomized controlled trial (CLEAN AIR study), air cleaner assignment had causal effect in improving COPD outcomes. It is unclear, however, what is the treatment effect among those for whom intervention reduced air pollution and whether it was reduction in fine particulate matter (PM2.5) or nitrogen dioxide (NO2) that contributed to such improvement. Because pollution is a posttreatment variable, treatment effect cannot be assessed while controlling for pollution using intention-to-treat (ITT) analysis. ObjectiveUsing principal stratification method, we assess indoor pollutants as the intermediate variable, and determine the causal effect of reducing indoor air pollution on COPD health. MethodIn randomized controlled trial, former smokers with COPD received either active or placebo HEPA air cleaners and were followed for 6 months. Saint George's Respiratory Questionnaire (SGRQ) was the primary outcome and secondary measures included SGRQ subscales, COPD assessment test (CAT), dyspnea (mMRC), and breathlessness, cough, and sputum scale (BCSS). Indoor PM2.5 and NO2 were measured. Principal stratification analysis was performed to assess the treatment effect while controlling for pollution reduction. ResultsAmong those showing at least 40 % PM2.5 reduction through air cleaners, the intervention showed improvement in respiratory symptoms for the active (vs. placebo), and the size of treatment effect shown for this subgroup was larger than that for the overall sample. In this subgroup, those with active air cleaners (vs. placebo) showed 7.7 points better SGRQ (95%CI: −14.3, −1.1), better CAT (β = −5.5; 95%CI: −9.8, −1.2), mMRC (β = −0.6; 95%CI: −1.1, −0.1), and BCSS (β = −1.8; 95%CI: −3.0, −0.5). Among those showing at least 40 % NO2 reduction through air cleaners, there was no intervention difference in outcomes. ConclusionAir cleaners caused clinically significant improvement in respiratory health for individuals with COPD through reduction in indoor PM2.5. Trial registrationClinicalTrials.gov: NCT02236858

A laboratory assessment of how biomass pellets could reduce indoor air pollution, mitigate climate change and benefit health compared to other solid fuels used in Ghana

To reduce indoor air pollution, the government of Ghana in 2019 formulated the renewable energy master plan to help disseminate biomass pellets and stoves to 2,000,000 households by 2030. But pellets have neither been included in Ghana's energy mix nor have their surmised climate and health benefits been empirically assessed. This laboratory study tested emissions by burning wood, charcoal and pellets in improved cookstoves. It further modelled their associated indoor air pollution reduction, personal exposure, health benefits and climate impact for comparison. The emission factors based on useful energy delivered of CO, CO2 and PM2.5 were 3.506 ± 0.704, 306.6 ± 43.35, and 0.229 ± 0.039 g/MJdelivered, respectively, for wood rocket 1 stove; 2.115 ± 0.695, 272.8 ± 16.70, and 0.256 ± 0.166 g/MJdelivered for wood rocket 2 stove; 4.820 ± 1.098, 205.3 ± 60.49, and 0.051 ± 0.044 g/MJdelivered for charcoal 1 stove; 4.474 ± 1.525, 221.8 ± 65.71, 0.043 ± 0.040 g/MJdelivered for charcoal 2 stove; and 0.511 ± 0.325, 338.1 ± 45.41, and 0.041 ± 0.023 g/MJdelivered for pellet stove. The forced air supplied by the gasifier stove reduced pollutant emissions from pellet combustion. The 100-year global warming contribution of the pellet stove was lower than that of charcoal stoves, and was influenced by upstream emissions of fuel processing. The WHO (World Health Organization) models showed that a complete transition from wood to pellets in one million households could significantly improve health with most benefits for children below five years. However, the reported benefits can only be achieved if pellets are added to Ghana's energy mix. The government of Ghana can ensure a sustained adoption of pellets by fostering market enablers for supply and demand of pellets and gasifier stoves, and mitigating the factors that impact pellet production and use. Field evaluation of the economic, health and climate co-benefits of using pellets in Ghana is recommended for future study.