Use Of Air Filters Research Articles

Iatrogenic Diversion of Superior Vena Cava Into Left Atrium.

A 72-year-old woman presented at our hospital with symptoms of a cerebrovascular accident (CVA). Her medical history included repair of a sinus venosus atrial septal defect (SVASD) at age 4, dual-chamber pacemaker placement for complete heart block at age 60, and multiple CVAs. Her blood oxygen content was 86% on room air, and cardiac auscultation revealed a soft systolic flow murmur at the left sternal edge. An electrocardiogram (ECG) showed paced rhythm with right bundle branch block (Fig. 1A), and a chest radiograph showed a pacemaker wire protruding into the left ventricle (LV) (Fig. 1B). On a transthoracic echocardiogram (TTE), a saline contrast bubble study through the patient's left forearm showed bubbles appearing first in the left atrium (LA) and then in the LV, with no shunting (Fig. 2). A transesophageal echocardiogram (TEE) showed a single superior vena cava (SVC) draining into the LA (Fig. 3) with no shunting, as well as anomalous right pulmonary venous drainage into the SVC. A 3-dimensional TEE showed a pacemaker wire protruding into the LV (Fig. 4). A thoracic computed tomogram confirmed the ECG, TTE, and TEE findings (Fig. 5). Three months after the patient recovered from her CVA, she underwent elective double-patch repair of the anomalous SVC and right pulmonary venous drainage, removal of the old pacemaker leads, and placement of a new dual-chamber pacemaker.During the patient's childhood SVASD repair, a baffle was created between the SVC and LA instead of between the SVC and right atrium. Later, her pacemaker was placed incorrectly in the LV through this baffle. A dual-chamber paced rhythm normally shows left bundle branch morphology on an ECG; however, our patient's ECG showed right bundle branch morphology, suggesting that the pacemaker lead was protruding into the LV.Adult patients with an SVC-to-LA diversion present with either cyanosis or chronic hypoxemia, and they are at high risk for systemic embolization.1 Thus, intravenous infusions through the veins of the upper extremities should be avoided or be done with use of air filters.1,2 Regardless of clinical presentation, surgical correction is indicated upon diagnosis.3 In our patient, TTE and TEE were important in diagnosing an anomalous iatrogenic diversion of blood flow from the SVC into the LA, and computed tomography was crucial in delineating its anatomy.

The Role of Environmental Risk Factors on the Development of Childhood Allergic Rhinitis.

Environmental factors play an important role in the development and exacerbation of allergic rhinitis (AR) in childhood. Indoor air pollution, such as house dust mites and secondhand smoke, can significantly increase the onset of AR, while pet dander may affect the exacerbation of AR symptoms in children. Furthermore, traffic related air pollution and pollen are outdoor air pollutants that can affect immune competency and airway responsiveness, increasing the risk of AR in children. Climate change has increased AR in children, as growth patterns of allergenic species have changed, resulting in longer pollen seasons. More extreme and frequent weather events also contribute to the deterioration of indoor air quality due to climate change. Additionally, viruses provoke respiratory tract infections, worsening the symptoms of AR, while viral infections alter the immune system. Although viruses and pollution influence development and exacerbation of AR, a variety of treatment and prevention options are available for AR patients. The protective influence of vegetation (greenness) is heavily associated with air pollution mitigation, relieving AR exacerbations, while the use of air filters can reduce allergic triggers. Oral antihistamines and intranasal corticosteroids are common pharmacotherapy for AR symptoms. In this review, we discuss the environmental risk factors for AR and summarize treatment strategies for preventing and managing AR in children.

Monitoring of polycyclic aromatic hydrocarbons (PAHs) in smoke of charcoal grilled meat-restaurants in Amman, Jordan

Polycyclic aromatic hydrocarbons (PAHs) were investigated in the outdoor air of charcoal-grilled meat-restaurants in Amman/Jordan. The studied restaurants were given the codes (S, Z, G, B, and J). PAHs were extracted using QuEChERS method and detected using GC/MS. They were found in almost all samples. Levels of PAHs in the stacks were found to depend on major factors like type and quantity of charcoal used, the amount of grilled meat after marinating, and sampling season. The results showed that PAHs concentrations in toxic equivalents (TEQs) in (ng TEQ/m3) were found in the following order: S restaurant (158) > B (114) > J (47) > G (20) > Z (15). The total emissions of PAHs in (g TEQ/year) for all restaurants samples were in the following order: S restaurant (16.5) > B (5.8) > J (1.8) > G (0.3) > Z (0.2) with B(a)P detected in restaurants S and B. This study is the first of its kind in the MENA region and provides alarming results about using charcoal for grilling where food and air contamination is unavoidable. Lowering consumption of grilled food is advisable in addition to the use of air filters for chimneys.

The Effect of Particulate Matter Reduction by Indoor Air Filter Use on Respiratory Symptoms and Lung Function: A Systematic Review and Meta-analysis.

PurposeExposure to particulate matter (PM) is a key public health issue, but effective intervention has not yet been established. A systematic literature review and meta-analysis has been conducted to assess the relationship between the use of air filters, one of the most commonly studied interventions, and respiratory outcomes in patients with chronic respiratory diseases.MethodsWe systematically reviewed intervention studies on PM using PubMed, EMBASE, and Cochrane databases up to September 2019. Studies that included data on PM concentration changes and respiratory symptoms or lung function in patients with respiratory diseases were eligible for inclusion. Effect estimates were quantified separately using the random-effects model.ResultsSix studies were included in the quantitative analysis. Air filter use reduced indoor PM2.5 by 11.45 µg/m3 (95% confidence interval [CI], 6.88, 16.01 µg/m3). Air filter use was not associated with improvements in respiratory symptoms in 5 of the 6 studies or significant changes in the predicted forced expiratory volume in one second (FEV1) (mean change, −1.77%; 95% CI, −8.25%, 4.71%). Air filter use was associated with improved peak expiratory flow rate by 5.86 (95% CI, 3.5, 8.19 of standardized difference).ConclusionsThe findings of this systematic review suggest that air filters may reduce indoor PM and increase peak expiratory rate in asthmatic patients. However, most studies showed no significant effects of air filters on respiratory symptoms or FEV1. Further studies in regions with high-density PM may provide additional information on this issue.Trial RegistrationPROSPERO Identifier: CRD42020156258

The effect of particulate matter reduction by indoor air filter use on respiratory symptoms and lung function

Background: Exposure to particulate matter (PM) is a key public health issue, but effective intervention has not yet been established. A systematic literature review and meta-analysis has been conducted to assess the relationship between the use of air filters, one of the most-studied interventions, and respiratory outcomes in patients with chronic respiratory disease. Methods: Studies that included data on PM level changes and respiratory symptoms or lung function in patients with respiratory diseases were eligible for inclusion. Chronic respiratory diseases included asthma, COPD, bronchiectasis and interstitial lung disease. Effect estimates were quantified separately using the random-effects model. Results: Among 1522 related articles, a total of 18 effect estimates from seven studies were included. Of seven eligible studies, six were randomized controlled trials, and one was a randomized cross-over study. The study population was pediatric asthmatics (n=6) or adult COPD patients (n=1). In all enrolled studies, air filter use reduced indoor PM2.5 significantly and the model yielded a pooled estimated of absolute difference in PM2.5 of 11.45 µg/m3 (95% confidence interval [CI]: 16.01-6.88 µg/m3). Air filter use improved predicted forced expiratory volume in one second (FEV1) significantly with 3.60% (95% CI: 0.29-6.90%, a random effect model). Air filter use was not associated with a significant change in respiratory symptoms (odds ratio: 0.82; 95% CI: 0.62-1.08). Conclusion: Study evidence indicates a statistically significant association between the use air filters and increased lung function with significant reduction of indoor PM2.5.

Home Air Filtration for Traffic-Related Air Pollution: Study Design and Methods

Despite reducing indoor particulate matter (PM) pollution from traffic, it is not established that freestanding air filters in homes benefits cardiovascular health. We are launching a randomized crossover efficacy trial of high efficiency particulate arrestance (HEPA) filters in homes near a highway in Somerville, MA, USA. The approach is community-engaged research with active participation of community partners. Drawing on lessons from our pilot studies, we will focus on colder seasons when windows are less likely to be open and exclude participants with serious health problems or use of antihypertensive or anti-inflammatory medications. Over 3.5 years we will recruit 210 homes with 240 study participants aged 40-75. Each home will receive, in random order, two HEPA units either with or without (sham) filters for one month. Following a one-month wash out period, the filtration condition will be reversed. We will exclude smoking households and people who work at jobs with significant PM exposure. At baseline and at one-month intervals we will interview each participant for demographics, relevant behaviors and health symptoms. Blood pressure (central and peripheral) and blood draws taken at monthly intervals will be the primary health outcomes. Blood samples will be stored at -80 ᵒC and analyzed for inflammatory (IL-6) and coagulation (D-dimer) biomarkers. Secondary outcomes will be metabolome, asthma, allergy and cognitive function. We will monitor particle number concentration, PM2.5, PM size distribution and composition in a subset of homes for one week each during filtration and sham. Time activity will be self-reported monthly and we will measure time spent in the rooms with filters for a subset using custom Bluetooth technology. The results will provide evidence for or against use of air filters in homes to reduce health effects of traffic-related PM. We will investigate participant experience and reasons for compliance via interviews.

Development of a new personal air filter test system using a low-cost particulate matter (PM) sensor

The extensive use of air filters has encouraged advances in both the fabrication and characterization of air filter technology. An affordable and accessible means of assessing the quality of air fi...

Modeling the Impact of an Indoor Air Filter on Air Pollution Exposure Reduction and Associated Mortality in Urban Delhi Household.

Indoor exposure to fine particulate matter (PM2.5) is a prominent health concern. However, few studies have examined the effectiveness of long-term use of indoor air filters for reduction of PM2.5 exposure and associated decrease in adverse health impacts in urban India. We conducted 20 simulations of yearlong personal exposure to PM2.5 in urban Delhi using the National Institute of Standards and Technology’s CONTAM program (NIST, Gaithersburg, MD, USA). Simulation scenarios were developed to examine different air filter efficiencies, use schedules, and the influence of a smoker at home. We quantified associated mortality reductions with Household Air Pollution Intervention Tool (HAPIT, University of California, Berkeley, CA, USA). Without an air filter, we estimated an annual mean PM2.5 personal exposure of 103 µg/m3 (95% Confidence Interval (CI): 93, 112) and 137 µg/m3 (95% CI: 125, 149) for households without and with a smoker, respectively. All day use of a high-efficiency particle air (HEPA) filter would reduce personal PM2.5 exposure to 29 µg/m3 and 30 µg/m3, respectively. The reduced personal PM2.5 exposure from air filter use is associated with 8–37% reduction in mortality attributable to PM2.5 pollution in Delhi. The findings of this study indicate that air filter may provide significant improvements in indoor air quality and result in health benefits.

Microbiological Quality of Indoor Air in Some Selected Buildings at Modibbo Adama University of Technology, Yola

The study aimed at investigating the quality of indoor air quality in some selected buildings at Modibbo Adama University of Technology Yola, Nigeria. Air samples were taken twice a week, morning and afternoon using settle plate method. In all the tested buildings a multiple growth of bacterial colonies and fungal spores were observed in the afternoons when compared to morning. The predominant bacteria isolated from the air samples were Staphylococcus aureus with frequency of 87.4%, Micrococcus spp. with frequency of 80.6%, Klebsiella pneumonia spp. with frequency of 47.0%, Actinomyces spp. with frequency 43.7% and Serratia mercenscens with frequency of 23.5%, while the isolated fungi included Cladosporium spp. with frequency of 66.2%, Aspergillus spp. with frequency of 57.6%, Penicillium spp. with frequency of 51.8% and Alternaria spp. with the frequency of 31.7%. The result of the determination of bacterial andfungal count showed that the highest count was found in the afternoon with461 CFU/m3 and 418 CFU/m3 while the lowest count in the morning with94 CFU/m3and 83 CFU/m3for both bacteria and fungi respectively. Among these microbes the presence of opportunistic pathogens that are involved in the establishment of sick building syndrome and saprophytic microflora which is generally associated to human skin and mucosa was detected. Possible causes of indoor air quality problem should be analyzed in order to retain healthy indoor environments. The level of air contamination can be reduced by the application of some chemical and physical agents such as ultraviolet radiation and the use of air filters which has great potential value for reducing the microbial flora of the air.

Bedroom exposure to airborne allergens in the Chicago area using a patient-operated sampling device

BackgroundIn current practice, allergens in vacuum-collected dust are used as surrogates for inhalable allergens. We developed an air-sampling device that can be used by patients for direct measurement of airborne allergen concentrations in their own homes. ObjectiveTo demonstrate the use of this device to establish allergen concentration reference ranges in a target population and to evaluate associations between patient-reported information and measured allergen concentrations. MethodsPatients from 5 allergist's practices in the Chicagoland region were provided with instructions, questionnaires, informed consent forms, and samplers to run for 5 days in their bedrooms. Samples were collected from cartridges and assayed by multiplex immunoassays for 12 common household allergens and enzyme-linked immunosorbent assay for ragweed. ResultsUnique allergen profiles were obtained for 102 patient homes. Samples with allergen concentrations above the limit of detection were as follows: total dust mite, 28%; cat, 61%; dog, 64%; mouse, 12%; rat, 0%; cockroach, 4%; Alternaria, 6%; Aspergillus, 21%; birch pollen 1%; grass, 8%; and ragweed, 5%. Of those, 75 completed questionnaires, providing meta-data for further analysis. Pet allergens correlated significantly with number of pets owned. Humidity correlated with dust mite allergens, open windows with Alternaria and mouse allergens, and high-efficiency particulate air filter use with reduced levels of several allergens. Many other variables showed no significant correlations. ConclusionThe combination of ease of use, high air-sampling rate, and sensitive immunoassays permitted the measurement of airborne allergen concentrations in homes and establishment of reference ranges. Patient-reported information permitted identification of factors that could relate to allergen concentrations and suggested remedial measures.

A randomized double‐blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community

Few studies have examined indoor air quality in First Nations communities and its impact on cardiorespiratory health. To address this need, we conducted a crossover study on a First Nations reserve in Manitoba, Canada, including 37 residents in 20 homes. Each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week. Indoor air pollutants were monitored throughout the study period. Indoor PM2.5 decreased substantially during air filter weeks relative to placebo (mean difference: 37 μg/m(3) , 95% CI: 10, 64) but remained approximately five times greater than outdoor concentrations owing to a high prevalence of indoor smoking. On average, air filter use was associated with a 217-ml (95% CI: 23, 410) increase in forced expiratory volume in 1 s, a 7.9-mm Hg (95% CI: -17, 0.82) decrease in systolic blood pressure, and a 4.5-mm Hg (95% CI: -11, 2.4) decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM2.5 and lung function. In general, our findings suggest that reducing indoor PM2.5 may contribute to improved lung function in First Nations communities. Indoor air quality is known to contribute to adverse cardiorespiratory health, but few studies have examined indoor air quality in First Nations communities. Our findings suggest that indoor PM2.5 may contribute to reduced lung function and that portable air filters may help to alleviate these effects by effectively reducing indoor levels of particulate matter.

Investigation on lowering commuters’ in-cabin exposure to ultrafine particles

To determine ways to reduce commuters’ ultrafine particle exposure, factors such as ventilation condition, mechanical airflow rate, driving speed, cabin air filter quality, and cabin air filter use are examined. The results show that the in-cabin to on-roadway ratio is reduced by 20% when the fan is set to recirculation-on versus when set to recirculation-off because fewer ultrafine particles are exchanged between the inside and outside of the cabin. Also, when the fan is set to recirculation-off, the ratio is reduced by 40% at lower mechanical airflow rates. The thickest cabin air filter resulted in a 30% in-cabin to on-roadway ratio decrease compared with the thinnest. Thus, driving conditions with the least UFP in-cabin to on-roadway ratio is when a vehicle is operating with a high efficiency cabin filter, the ventilation set to fan-on and recycling is recirculation on, and at a high ventilation airflow rate. Furthermore, recirculating in-cabin air through a high efficiency particulate air filter was found to significantly reduce in-cabin UFP exposure.

Air Change Rates and Interzonal Flows in Residences, and the Need for Multi-Zone Models for Exposure and Health Analyses

Air change rates (ACRs) and interzonal flows are key determinants of indoor air quality (IAQ) and building energy use. This paper characterizes ACRs and interzonal flows in 126 houses, and evaluates effects of these parameters on IAQ. ACRs measured using weeklong tracer measurements in several seasons averaged 0.73 ± 0.76 h−1 (median = 0.57 h−1, n = 263) in the general living area, and much higher, 1.66 ± 1.50 h−1 (median = 1.23 h−1, n = 253) in bedrooms. Living area ACRs were highest in winter and lowest in spring; bedroom ACRs were highest in summer and lowest in spring. Bedrooms received an average of 55 ± 18% of air from elsewhere in the house; the living area received only 26 ± 20% from the bedroom. Interzonal flows did not depend on season, indoor smoking or the presence of air conditioners. A two-zone IAQ model calibrated for the field study showed large differences in pollutant levels between the living area and bedroom, and the key parameters affecting IAQ were emission rates, emission source locations, air filter use, ACRs, interzonal flows, outdoor concentrations, and PM penetration factors. The single-zone models that are commonly used for residences have substantial limitations and may inadequately represent pollutant concentrations and exposures in bedrooms and potentially other environments other where people spend a substantial fraction of time.

Paradoxical air embolism following contrast material injection through power injectors in patients with a patent foramen ovale

In patients with a patent foramen ovale, use of air filters during intravenous infusions is common, but they are not compatible with power injection. Therefore we aimed to assess the incidence of paradoxical air embolism on CT of the chest and brain following contrast material injection through a power injector in patients with a patent foramen ovale, without the use of a filter. In this IRB approved, HIPAA compliant retrospective study, two independent radiologists reviewed 289 CT scans of the chest (n = 233) and brain (n = 56) for vascular air embolism following contrast material injection through a power injector in 93 subjects (43 men, mean age 66 y) with a known patent foramen ovale. The location and amount of the air were assessed. The medical records were reviewed for embolic symptoms. The prevalence and location of right sided and systemic luminal air were determined and inter-observer agreement for detection of intraluminal vascular air was calculated. Vascular air embolism was observed in 19.3% (56/289) of the studies; small in 52 and moderate in 4. In 42 studies, intravascular air was seen in a single territory and 14 studies had intravascular air in multiple territories. None had air in the left side of the heart or brain to suggest paradoxical air embolism. The inter-observer agreement for detection of vascular air was moderate (k = 0.6). Paradoxical air embolism in patients with a patent foramen ovale following contrast material injection with a power injector is rare.

Physicians' Perceptions and Practices Regarding Patient Reports of Multiple Chemical Sensitivity

Ninety physicians practicing in the state of Virginia USA completed a mail survey regarding Multiple Chemical Sensitivity (MCS). Survey questions addressed demographics; familiarity with MCS; etiology; overlapping conditions; accommodations made for patients and practices regarding evaluation, treatment, and referral. A little over half of respondents were familiar with MCS. Under a third had received any medical training regarding chemical sensitivity, only 7% were “very satisfied” with their knowledge, and 6% had a treatment protocol for the condition. Participants cited a range of etiologies and overlapping conditions including asthma, Reactive Airway Dysfunction Syndrome (RADS), Sick Building Syndrome (SBS), Chronic Fatigues Syndrome (CFS), and Fibromyalgia. Physicians infrequently considered chemicals as a cause of illness when seeing new patients. Evaluation techniques included interviews, blood work, immune profiles, and allergy testing. Interventions recommended included chemical avoidance, alterations in the home environment, diet restrictions, the use of air filters, and referrals to outside specialists.

Water and air management systems for a passive direct methanol fuel cell

In this paper water and air management systems were developed for a miniature, passive direct methanol fuel cell (DMFC). The membrane thickness, water management system, air management system and gas diffusion electrodes (GDE) were examined to find their effects on the water balance coefficient, fuel utilization efficiency, energy efficiency and power density. Two membranes were used, Nafion ® 112 and Nafion ® 117. Nafion ® 117 cells had greater water balance coefficients, higher fuel utilization efficiency and greater energy efficiency. A passive water management system which utilizes additional cathode gas diffusion layers (GDL) and a passive air management system which makes use of air filters was developed and tested. Water management was improved with the addition of two additional cathode GDLs. The water balance coefficients were increased from −1.930 to 1.021 for a cell using a 3.0 mol kg −1 solution at a current density of 33 mA cm −2. The addition of an air filter further increased the water balance coefficient to 1.131. Maximum power density was improved from 20 mW cm −2 to 25 mW cm −2 for 3.0 mol kg −1 solutions by upgrading from second to third generation GDEs, obtained from E-TEK. There was no significant difference in water management found between second and third generation GDEs. A fuel utilization efficiency of 63% and energy efficiency of 16% was achieved for a 3.0 mol kg −1 solution with a current density of 66 mA cm −2 for third generation GDEs.

Effect of Air Filtration Systems on Asthma: A Systematic Review of Randomized Trials

To systematically review the evidence of randomized trials evaluating the effects of residential air filtration systems on patients with asthma. We searched for published and unpublished studies using MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Collaboration. We reviewed all reference lists for additional articles of relevance, and contacted experts in the field and air filter manufacturers. We identified 10 relevant randomized controlled trials that examined the influence of a residential air filtration system on patients with asthma. In duplicate and independently, we abstracted data on the methodologic quality, population, intervention, and outcomes. Five of 10 studies enrolled adults only. One study included children only. The sample size ranged from 9 to 45 participants in each study, for a total of 216 patients across all studies. Two studies reported a statistically significant decrease in airway responsiveness associated with air filter utilization. Air filters were associated with significantly lower total symptom scores (weighted mean difference of 0.47; 95% confidence interval [CI], 0.69 to 0.25) on a 10-point scale, and lower sleep disturbance score (weighted mean difference of 0.93; 95% CI, 1.44 to 0.42); however, heterogeneity of results weakens the inferences from these trials. Air filtration systems were not associated with any differences in medication use or morning peak expiratory flow values. None of these trials employed validated scales to measure clinical symptoms or quality of life. Among patients with allergies and asthma, use of air filters is associated with fewer symptoms. Rigorous sufficiently powered randomized clinical trials are needed to more precisely define the influence of air filtration on health-related quality of life and symptom control for asthmatic patients.