Solid fuel use and cardiovascular events: A systematic review and meta-analysis of observational studies

Although solid fuel use has been increasingly linked to cardiovascular events (CVEs), conclusions have been inconsistent. We systematically searched 3 databases (PubMed, Embase, and Web of Science) up to July 3, 2020, to identify English language reports that assessed the association of solid fuel use with CVEs. Summary relative risks (RRs) and 95% confidence intervals (CIs) were estimated with a random-effects model. Subgroup analyses and sensitivity analyses were conducted to explore the potential sources of heterogeneity and to test the stability of the results. We finally included 13 observational studies (8 cohort, 3 cross-sectional, and 2 case-control studies comprising 791,220 participants) in the meta-analysis. The risk of CVEs was increased 21% with the highest versus the lowest solid fuel use (highest/lowest, RR_pooled = 1.21, 95% CI: 1.10–1.34). As for the subgroup analyses on study design, the pooled RR for cohort studies, case-control studies, and cross-sectional studies were 1.11 (95%CI: 1.03–1.19), 4.80 (95%CI: 2.22–10.39), and 1.46 (95%CI: 0.82–2.62), respectively. The results of this study suggested that high solid fuel use was associated with increased CVE risk, and that reducing the use of solid fuel will be important for improving the health of the populations in developing countries.     

室内空气中甲醛的去除

介绍了物理吸附法、化学法和生物法等去除甲醛的方法的研究概况,指出了今后的研究方向.     

A review on reducing indoor particulate matter concentrations from personal-level air filtration intervention under real-world exposure situations

Improving air quality in indoor environments where people live is of importance to protect human health. In this systematic review, we assessed the effectiveness of personal-level use of air filtration units in reducing indoor particulate matters (PM) concentrations under real-world situations following systematic review guidelines. A total of 54 articles were included in the review, in which 20 randomized controlled/crossover trials that reported the changes in indoor fine PM (PM_2.5) concentrations were quantitatively assessed in meta-analysis. Standardized mean differences (SMDs) were calculated for changes in indoor PM concentrations following air filtration interventions. Moderate-to-large reductions of 11%–82% in indoor PM_2.5 concentrations were observed with SMD of −1.19 (95% CI: −1.50, −0.88). The reductions in indoor PM concentrations varied by geographical locations, filtration technology employed, indoor environmental characteristics, and air pollution sources. Most studies were graded with low-to-moderate risk of bias; however, the overall certainty of evidence for indoor PM concentration reductions was graded at very low level. Considering the effectiveness of indoor air filtration under practical uses, socio-economic disparities across study populations, and costs of air filter replacement over time, our results highlight the importance of reducing air pollution exposure at the sources.     

Association between indoor mold and asthma among children in Buffalo, New York

Asthma is a leading chronic disease among children and places a significant burden on public health. Exposure to indoor mold has been associated with asthma symptoms. However, many mold assessments have relied on visual or other identification of damp conditions and mold presence, thus have not examined associations with specific fungal genera. The objective of this case-control study was to examine the relationship between airborne mold concentrations and asthma status among children and to identify the contribution from specific mold genera in air. Participants completed a questionnaire of home environmental conditions and underwent indoor air sampling in the home, from which viable and total-count fungal spores were quantified. The most prevalent fungi in the homes were the allergenic molds Cladosporium (98% and 87% of homes from viable and total count samples, respectively) and Penicillium (91% and 73%). There were no significant differences in mean fungal concentrations between the homes of cases and controls, although the observed rate of exposure to several molds was higher among the cases. Among children who lacked a family history of asthma, cases had significantly higher exposures to viable Aspergillus. Measured humidity levels in the home corresponded with some self-reported indicators of mold and dampness. PRACTICAL IMPLICATIONS: The results of this study support existing literature that indoor fungal exposures play a role in current asthma status and that some qualitative assessments of mold exposure correspond to fungi present in indoor air.     

Indoor microbiome and risk of lower respiratory tract infections among children under-five years: A meta-analysis

We investigated whether exposure to microbiome within the indoor environment is associated with risk of lower respiratory tract infections (LRTI) among children under 5 years of age. Electronic scientific repositories; PubMed, Scopus, Web of Science, GreenFILE, EMBASE, and Cochrane library were searched and screened through July 2019 for published reports for inclusion in the meta-analysis. Studies were eligible for inclusion if they reported an adjusted measure of risk for LRTI associated with IM exposure, including the relative risk (RR) or odds ratio (OR) and confidence interval (CI). The pooled OR was computed using the inverse of variance method for weighting. Sensitivity analysis was used to evaluate the effect of individual studies, while heterogeneity was evaluated by I² statistics using RevMan 5.3. Seven studies were eligible for inclusion in our meta-analysis. Exposure to a higher concentration of IM was associated with an increased risk of LRTI [OR:1.20 (1.11, 1.33), P < .0001]. The risk was stronger with exposure to total fungal concentration [OR:1.27 (1.13, 1.44), P < .0001] than visible molds [OR:1.20 (1.07, 1.34, P = .001]. Under-five children exposed to higher IM concentration are likely at increased risk of LRTI. Interventions addressing IM exposure should be considered in the management of LRTI among under-five children.     

Residential indoor air quality interventions through a social-ecological systems lens: A systematic review

Indoor air quality (IAQ) is an important consideration for health and well-being as people spend most of their time indoors. Multi-disciplinary interest in IAQ is growing, resulting in more empirical research, especially in affordable housing settings, given disproportionate impacts on vulnerable populations. Conceptually, there is little coherency among these case studies; they traverse diverse spatial scales, indoor and outdoor environments, and populations, making it difficult to implement research findings in any given setting. We employ a social-ecological systems (SES) framework to review and categorize existing interventions and other literature findings to elucidate relationships among spatially and otherwise diverse IAQ factors. This perspective is highly attentive to the role of agency, highlighting individual, household, and organizational behaviors and constraints in managing IAQ. When combined with scientific knowledge about the effectiveness of IAQ interventions, this approach favors actionable strategies for reducing the presence of indoor pollutants and personal exposures.     

室内颗粒物的来源和特点研究

分析了国内外在室内颗粒物的来源和室内外颗粒源对室内颗粒物浓度的影响方面的研究进展。指出了目前研究中存在的问题,并对未来的研究方向进行了展望。     

Classrooms' indoor environmental conditions affecting the academic achievement of students and teachers in higher education: A systematic literature review

This study reports the outcomes of a systematic literature review, which aims to determine the influence of four indoor environmental parameters — indoor air, thermal, acoustic, and lighting conditions —on the quality of teaching and learning and on students' academic achievement in schools for higher education, defined as education at a college or university. By applying the Cochrane Collaboration Method, relevant scientific evidence was identified by systematically searching in multiple databases. After the screening process, 21 publications of high relevance and quality were included. The collected evidence showed that the indoor environmental quality (IEQ) can contribute positively to the quality of learning and short-term academic performance of students. However, the influence of all parameters on the quality of teaching and the long-term academic performance could not be determined yet. Students perform at their best in different IEQ conditions, and these conditions are task-dependent, suggesting that classrooms which provide multiple IEQ classroom conditions facilitate different learning tasks optimally. In addition, the presented evidence illuminates how to examine the influence of the IEQ on users. Finally, this information supports decision-makers in facility management and building systems engineering to improve the IEQ, and by doing so, allow teachers and students to perform optimally.     

A review: fungal exposure assessment in indoor environments

While the fungal exposure assessment was based on the determination of fungal propagules for a long time, recent progress has led to the development of methodology for other fungal agents, e.g. the fungal cell wall components, metabolites, and allergens, that may be responsible for health effects caused by fungal exposure. This review includes a summary of the sampling techniques and analytical methods that are currently used or are in progress for the fungal exposure assessment. Prospects for the future trends are also discussed. In the future, the development will focus on sampling techniques that allow longer sampling times, a higher sampling efficiency for relevant particle sizes, and better possibilities for a wide range of analyses. In addition, new or modified methodology based on chemical, immunochemical, and molecular biological techniques to measure fungal agents related to health effects will improve the understanding of biological responses caused by fungal exposure.     

Indoor exposure levels of bacteria and fungi in residences,schools, and offices in China: A systematic review

Microbes in buildings have attracted extensive attention from both the research community and the general public due to their close relationship with human health. However, there still lacks comprehensive information on the indoor exposure level of microbes in China. This study systematically reviews exposure levels, the community structures, and the impact factors of airborne bacteria and fungi in residences, schools, and offices in China. We reviewed the major literature databases between 1980 and 2019 and selected 55 original studies based on a set of criteria. Results show that the concentration of indoor bacteria varies from 72.5 to 7500 CFU/m³, with a median value of 1000 CFU/m³, and the concentration of fungi varies from 12 to 9730 CFU/m³, with a median value of 526 CFU/m³. The concentration level of microbes varies in different climate zones, with higher bacterial concentrations in the severe cold zone, and higher fungal concentrations in the hot summer and warm winter zone. Among different buildings, classrooms have the highest average bacteria and fungi levels. This review reveals that a unified assessment system based on health effects is needed for evaluating the exposure levels of bacteria and fungi.     

室内装修材料中甲醛污染物的检测与防治方法

室内空气污染问题已成为近年来城市居民关注的热点问题之一。装修材料中挥发性有机污染物进入空气,对人体健康造成很大威胁,本文介绍了室内装修中空气污染物甲醛的来源、特点及检测方法,提出了降解室内甲醛污染物的防治措施。     

A systematic evaluation of accelerating indoor airflow simulations using cross-platform parallel computing

With new advances in computer hardware and software, users now have widespread accessibility to multicore devices inside personal computers making it feasible for fast indoor airflow simulations. Some exciting preliminary results of a cross-platform parallel computing framework OpenCL using specific hardware were reported. However, those results are largely based on two hypotheses: 1. OpenCL code on all devices will generate the same results; 2. On the same device, running in parallel with multiple processors will be faster than running in sequential with a single processor. This study attempted to evaluate these two hypotheses by systematically studying the accuracy and computing speed of OpenCL for indoor airflow simulations. A Fast Fluid Dynamics (FFD) code was selected as an exemplar indoor airflow simulation program. To compare the cross-platform ability of OpenCL, the evaluation was performed using four Graphics Processing Units (GPUs) and five Central Processing Units (CPUs) from three manufacturers, with different degrees of computing capability and mounted on two operating systems. The test subjects were evaluated using four case studies consisting of various indoor airflows. A sequential FFD code programmed in C and a Computational Fluid Dynamics (CFD) program were first used to perform the case studies and generate numerical benchmarks. The comparison of the numerical simulation results with experimental data showed that CFD and FFD can predict the studied flows with averaged relative errors of 9.99% and 11.30%, respectively. Afterwards, the accuracy and speedup of the OpenCL code was compared with numerical benchmarks. Although the OpenCL code on the CPUs generated identical numerical results, the OpenCL results from the GPUs were slightly dissimilar. This is likely due to varying interpretations, by the manufactures, of an Institute of Electrical and Electronics Engineers standard. Depending on the hardware, the speedups of the OpenCL code varied from 0.7 to 4.2 times on the CPUs and 5.1–129.3 times on the GPUs. The slowdown of computing speed happened when running OpenCL on a two-core CPU in a Windows Operating System using the Boot Camp on a Mac computer. Finally, a separate study on the relationship between speedup and global work size showed that a speedup of 1139 can be achieved when using an AMD FirePro W8100 GPU.     

Effectiveness of portable HEPA air cleaners on reducing indoor endotoxin,PM10, and coarse particulate matter in an agricultural cohort of children with asthma: A randomized intervention trial

We conducted a randomized trial of portable HEPA air cleaners in the homes of children age 6–12 years with asthma in the Yakima Valley, Washington. All families received asthma education while intervention families also received two HEPA cleaners (child's bedroom, living room). We collected 14-day integrated samples of endotoxin in settled dust and PM₁₀ and PM_10-2.5 in the air of the children's bedrooms at baseline and one-year follow-up, and used linear regression to compare follow-up levels, adjusting for baseline. Seventy-one families (36 HEPA, 35 control) completed the study. Baseline geometric mean (GSD) endotoxin loadings were 1565 (6.3) EU/m² and 2110 (4.9) EU/m², respectively, in HEPA vs. control homes while PM₁₀ and PM_10-2.5 were 22.5 (1.9) μg/m³ and 9.5 (2.9) μg/m³, respectively, in HEPA homes, and 19.8 (1.8) μg/m³ and 7.7 (2.0) μg/m³, respectively, in control homes. At follow-up, HEPA families had 46% lower (95% CI, 31%–57%) PM₁₀ on average than control families, consistent with prior studies. In the best-fit heterogeneous slopes model, HEPA families had 49% (95% CI, 6%–110%) and 89% lower (95% CI, 28%–177%) PM_10-2.5 at follow-up, respectively, at 50th and 75th percentile baseline concentrations. Endotoxin loadings did not differ significantly at follow-up (4% lower, HEPA homes; 95% CI, −87% to 50%).     

Effectiveness of portable HEPA air cleaners on reducing indoor PM2.5 and NH3 in an agricultural cohort of children with asthma: A randomized intervention trial

We conducted a randomized trial of portable HEPA air cleaners with pre-filters designed to also reduce NH₃ in non-smoking homes of children age 6-12 with asthma in Yakima Valley (Washington, USA). Participants were recruited through the Yakima Valley Farm Workers Clinic asthma education program. All participants received education on home triggers while intervention families additionally received two HEPA cleaners (child's sleeping area, main living area). Fourteen-day integrated samples of PM_2.5 and NH₃ were measured at baseline and one-year follow-up. We fit ANCOVA models to compare follow-up concentrations in HEPA vs control homes, adjusting for baseline concentrations. Seventy-one households (36 HEPA, 35 control) completed the study. Most were single-family homes, with electric heat and stove, A/C, dogs/cats, and mean (SD) 5.3 (1.8) occupants. In the sleeping area, baseline geometric mean (GSD) PM_2.5 was 10.7 (2.3) μg/m³ (HEPA) vs 11.2 (1.9) μg/m³ (control); in the living area, it was 12.5 (2.3) μg/m³ (HEPA) vs 13.6 (1.9) μg/m³ (control). Baseline sleeping area NH₃ was 62.4 (1.6) μg/m³ (HEPA) vs 65.2 (1.8) μg/m³ (control). At follow-up, HEPA families had 60% (95% CI, 41%-72%; p < .0001) and 42% (19%-58%; p = .002) lower sleeping and living area PM_2.5, respectively, consistent with prior studies. NH₃ reductions were not observed.     

Indoor exposure levels of ammonia in residences,schools, and offices in China from 1980 to 2019: A systematic review

Indoor ammonia (NH₃) pollution has been paid more and more attention in view of its health risk. However, few studies have investigated the exposure level in the non-occupational environment in China. This study systematically reviewed the indoor ammonia exposure level in different regions, the equivalent exposure concentration of different populations, and the factors that influence indoor air ammonia in residences, offices, and schools in China. The literature published in 1980–2019 from main databases was searched and detailed screened, and finally, 56 related studies were selected. The results illustrated that the median concentration of indoor air ammonia in residences, offices, and school buildings was 0.21 mg/m³, 0.26 mg/m³, and 0.15 mg/m³. There were 46.4%, 71.4%, and 40% of these samples exceeding the NH₃ standard, respectively. The national concentrations and the equivalent exposure levels of adults and children were calculated and found to be higher than 0.20 mg/m³. The concentration of ammonia varied greatly in different climate zones and economic development regions. Higher concentrations were found in the severe cold zone and the regions with higher economic level. This review reveals a high exposure risk of indoor air ammonia and the crucial impact of human emission, indoor air temperature, new concrete, and economic level, suggesting further investigation on indoor air ammonia evaluation and health effects.     

Gaseous formaldehyde removal: A laminated plate fabricated with activated carbon,polyimide, and copper foil with adjustable surface temperature and capable of in situ thermal regeneration

Formaldehyde is one of the most common indoor air pollutants in Chinese residences. This study introduces a novel laminated plate with adjustable surface temperature to remove gaseous formaldehyde. The plate is fabricated with activated carbon, polyimide, and copper foil via thermal compression. The plate can be regenerated in situ by applying a direct current to the copper foil. Adsorption‐regeneration cycle tests were conducted to evaluate the plate's formaldehyde removal performance. The overall removal efficiency of the fabricated laminated plate with glue mass fraction of 25% and thickness of 1.5 mm was about 30% at the face velocity of 0.8‐1.2 m/s. The pressure drop was about 5 Pa. Its removal ability can be regenerated in situ in 8 minutes by increasing the surface temperature to 80°C. The fabricated laminated plate showed good durability after 52 cycles of adsorption‐regeneration tests. The results indicate that the proposed laminated plate can enhance the purifying efficiency and enlarge the life span of ordinary, cheap sorbents. It makes cheap materials with low performance suitable for air purification.     

Asthma‐related outcomes associated with indoor air pollutants among schoolchildren from four informal settlements in two municipalities in the Western Cape Province of South Africa

The health impact of indoor air pollution in informal settlement households has not been extensively studied in South Africa. This cross‐sectional study investigated the association between asthma and common indoor exposures among schoolchildren from four informal settlements located in two municipalities in the Western Cape Province. A total of 590 children, aged 9‐11 years, were recruited. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was administered to caregivers. Pulmonary function assessment included spirometry and fractional exhaled nitric oxide (FeNO). Phadiatop test for atopy was done. The prevalence of doctor‐diagnosed asthma was 3.4% (n = 20) among whom only 50% were on treatment. The prevalence of current wheeze was 12.9%, and 17.6% had airway obstruction (FEV₁ < lower limit of normal), while 10.2% had airway inflammation (FeNO > 35 ppb). In adjusted logistic regression models, dampness, visible mold growth, paraffin use for cooking, and passive smoking were associated with a twofold to threefold increased risk in upper and lower airway outcomes. The strongest association was that of visible mold growth with rhinitis (adjusted odds ratio—aOR 3.37, 95% CI: 1.69‐6.71). Thus, there is a need for improved diagnosis of childhood asthma and Indoor Air Quality in informal settlement households.     

Long-term exposure to indoor air pollution and risk of tuberculosis

Indoor air pollution (IAP) is a recognized risk factor for various diseases. This paper examines the role of indoor solid fuel exposure in the risk of mycobacterium tuberculosis (TB) in Delhi Metropolitan, India. Using a cross-sectional design, subjects were screened for a history of active TB and lifelong exposure to IAP sources, such as solid fuel burning and kerosene. The TB prevalence rate in the study area was 1117 per 100 000 population. Every year, increase in solid fuel exposure was associated with a three percent higher likelihood of a history of active TB. Subjects exposed to solid fuel and kerosene use for both heating home and cooking showed significant associations with TB. Age, household expenditure (a proxy of income), lung function, and smoking also showed significant associations with TB. Smokers and solid fuel–exposed subjects were four times more likely to have a history of active TB than non-smoker and unexposed subjects. These finding calls strategies to mitigate solid fuel exposure, such as use of clean cookstove and ventilation, to mitigate the risk of TB which aligns with the United Nations’ goal of “End TB by 2030.”     

Dose–response relationships between mouse allergen exposure and asthma morbidity among urban children and adolescents

Home mouse allergen exposure is associated with asthma morbidity, but little is known about the shape of the dose–response relationship or the relevance of location of exposure within the home. Asthma outcome and allergen exposure data were collected every 3 months for 1 year in 150 urban children with asthma. Participants were stratified by mouse sensitization, and relationships between continuous measures of mouse allergen exposure and outcomes of interest were analyzed. Every tenfold increase in the bed mouse allergen level was associated with an 87% increase in the odds of any asthma‐related health care use among mouse‐sensitized [Odds Ratio (95% CI): 1.87 (1.21–2.88)], but not non‐mouse‐sensitized participants. Similar relationships were observed for emergency department visit and unscheduled doctor visit among mouse‐sensitized participants. Kitchen floor and bedroom air mouse allergen concentrations were also associated with greater odds of asthma‐related healthcare utilization; however, the magnitude of the association was less than that observed for bed mouse allergen concentrations. In this population of urban children with asthma, there is a linear dose–response relationship between mouse allergen concentrations and asthma morbidity among mouse‐sensitized asthmatics. Bed and bedroom air mouse allergen exposure compartments may have a greater impact on asthma morbidity than other compartments.     

Current wheeze,asthma, respiratory infections,and rhinitis among adults in relation to inspection data and indoor measurements in single‐family houses in Sweden—The BETSI study

In the Swedish Building Energy, Technical Status and Indoor environment study, a total of 1160 adults from 605 single‐family houses answered a questionnaire on respiratory health. Building inspectors investigated the homes and measured temperature, air humidity, air exchange rate, and wood moisture content (in attic and crawl space). Moisture load was calculated as the difference between indoor and outdoor absolute humidity. Totally, 7.3% were smokers, 8.7% had doctor’ diagnosed asthma, 11.2% current wheeze, and 9.5% current asthma symptoms. Totally, 50.3% had respiratory infections and 26.0% rhinitis. The mean air exchange rate was 0.36/h, and the mean moisture load 1.70 g/m³. Damp foundation (OR=1.79, 95% CI 1.16‐2.78) was positively associated while floor constructions with crawl space (OR=0.49, 95% CI 0.29‐0.84) was negatively associated with wheeze. Concrete slabs with overlying insulation (OR=2.21, 95% CI 1.24‐3.92) and brick façade (OR=1.71, 95% CI 1.07‐2.73) were associated with rhinitis. Moisture load was associated with respiratory infections (OR=1.21 per 1 g/m³, 95% CI 1.04‐1.40) and rhinitis (OR=1.36 per 1 g/m³, 95% CI 1.02‐1.83). Air exchange rate was associated with current asthma symptoms (OR=0.85 per 0.1/h, 95% CI 0.73‐0.99). Living in homes with damp foundation, concrete slabs with overlying insulation, brick façade, low ventilation flow, and high moisture load are risk factors for asthma, rhinitis, and respiratory infections.