Bronchiolitis recovery and the use of High Efficiency Particulate Air (HEPA) Filters (The BREATHE Study): study protocol for a multi-center, parallel, double-blind, randomized controlled clinical trial

BACKGROUND

Acute viral bronchiolitis is the most common reason for hospitalization of infants in the USA. Infants hospitalized for bronchiolitis are at high risk for recurrent respiratory symptoms and wheeze in the subsequent year, and longer-term adverse respiratory outcomes such as persistent childhood asthma. There are no effective secondary prevention strategies. Multiple factors, including air pollutant exposure, contribute to risk of adverse respiratory outcomes in these infants. Improvement in indoor air quality following hospitalization for bronchiolitis may be a prevention opportunity to reduce symptom burden. Use of stand-alone high efficiency particulate air (HEPA) filtration units is a simple method to reduce particulate matter ≤ 2.5 µm in diameter (PM2.5), a common component of household air pollution that is strongly linked to health effects.

METHODS

BREATHE is a multi-center, parallel, double-blind, randomized controlled clinical trial. Two hundred twenty-eight children < 12 months of age hospitalized for the first time with bronchiolitis will participate. Children will be randomized 1:1 to receive a 24-week home intervention with filtration units containing HEPA and carbon filters (in the child's sleep space and a common room) or to a control group with units that do not contain HEPA and carbon filters. The primary objective is to determine if use of HEPA filtration units reduces respiratory symptom burden for 24 weeks compared to use of control units. Secondary objectives are to assess the efficacy of the HEPA intervention relative to control on (1) number of unscheduled healthcare visits for respiratory complaints, (2) child quality of life, and (3) average PM2.5 levels in the home.

DISCUSSION

We propose to test the use of HEPA filtration to improve indoor air quality as a strategy to reduce post-bronchiolitis respiratory symptom burden in at-risk infants with severe bronchiolitis. If the intervention proves successful, this trial will support use of HEPA filtration for children with bronchiolitis to reduce respiratory symptom burden following hospitalization.

TRIAL REGISTRATION

NCT05615870. Registered on November 14, 2022.

High efficiency particulate air filters and heat & moisture exchanger filters increase positive end-expiratory pressure in helmet continuous positive airway pressure: A bench-top study

BACKGROUND

Helmet continuous positive airway pressure (CPAP) has been widely used during the COVID-19 pandemic. Specific filters (i.e. High Efficiency Particulate Air filter: HEPA; Heat & Moisture Exchanger Filter: HMEF) were used to prevent Sars-CoV2 environmental dispersion and were connected to the CPAP helmet. However, HEPA and HMEF filters may act as resistors to expiratory gas flow and increase the levels of pressure within the hood.

METHODS

In a bench-top study, we investigated the levels of airway pressure generated by different HEPA and HMEF filters connected to the CPAP helmet in the absence of a Positive End Expiratory Pressure (PEEP) valve and with two levels of PEEP (5 and 10 cmH2O). All steps were performed using 3 increasing levels of gas flow (60, 80, 100 L/min).

RESULTS

The use of 8 different commercially available filters significantly increased the pressure within the hood of the CPAP helmet with or without the use of PEEP valves. On average, the increase of pressure above the set PEEP ranged from 3 cmH2O to 10 cmH2O across gas flow rates of 60 to 100 L/min. The measure of airway pressure was highly correlated between the laboratory pressure transducer and the Helmet manometer. Bias with 95% Confidence Interval of Bias between the devices was 0.7 (-2.06; 0.66) cmH2O.

CONCLUSIONS

The use of HEPA and HMEF filters placed before the PEEP valve at the expiratory port of the CPAP helmet significantly increase the levels of airway pressure compared to the set level of PEEP. The manometer can detect accurately the airway pressure in the presence of HEPA and HMEF filters in the helmet CPAP and its use should considered.

Cytotoxicity and Characterization of Ultrafine Particles from Desktop Three-Dimensional Printers with Multiple Filaments

Previous research has indicated that ultrafine particles (UFPs, particles less than 100 nm) emitted from desktop three-dimensional (3D) printers exhibit cytotoxicity. However, only a limited number of particles from different filaments and their combinations have been tested for cytotoxicity. This study quantified the emissions of UFPs from a commercially available filament extrusion desktop 3D printer using three different filaments, including acrylonitrile butadiene Styrene (ABS), thermoplastic polyurethane (TPU), and polyethylene terephthalate glycol (PETG). In this study, controlled experiments were conducted where the particles emitted were used to expose cells grown in an air-liquid interface (ALI) system. The ALI exposures were utilized for in vitro characterization of particle mixtures, including UFPs from a 3D printer. Additionally, a lactate dehydrogenase (LDH) assay was used to evaluate the cytotoxic effects of these UFPs. A549 cells were exposed at the ALI to UFPs generated by an operational 3D printer for an average of 45 and 90 min. Twenty-four hours post-exposure, the cells were analyzed for percent cytotoxicity in a 24-well ALI insert (LDH assay). UFP exposure resulted in diminished cell viability, as evidenced by significantly increased LDH levels. The findings demonstrate that ABS has the most significant particle emission. ABS was the only filament that showed a significant difference compared to the high efficiency particulate arrestance (HEPA) following 90 min of exposure (p-value < 0.05). Both ABS and PETG exhibited a significant difference compared to the HEPA control after 45 min of exposure. A preliminary analysis of potential exposure to these products in a typical environment advises caution when operating multiple printer and filament combinations in poorly ventilated spaces or without combined gas and particle filtration systems.

Improved indoor air quality during desert dust storms: The impact of the MEDEA exposure-reduction strategies

Desert dust storms (DDS) are natural events that impact not only populations close to the emission sources but also populations many kilometers away. Countries located across the main dust sources, including countries in the Eastern Mediterranean, are highly affected by DDS. In addition, climate change is expanding arid areas exacerbating DDS events. Currently, there are no intervention measures with proven, quantified exposure reduction to desert dust particles. As part of the wider "MEDEA" project, co-funded by LIFE 2016 Programme, we examined the effectiveness of an indoor exposure-reduction intervention (i.e., decrease home ventilation during DDS events and continuous use of air purifier during DDS and non-DDS days) across homes and/or classrooms of schoolchildren with asthma and adults with atrial fibrillation in Cyprus and Crete-Greece. Participants were randomized to a control or intervention groups, including an indoor intervention group with exposure reduction measures and the use of air purifiers. Particle sampling, PM₁₀ and PM_2.5, was conducted in participants' homes and/or classrooms, between 2019 and 2022, during DDS-free weeks and during DDS days for as long as the event lasted. In indoor and outdoor PM₁₀ and PM_2.5 samples, mass and content in main and trace elements was determined. Indoor PM_2.5 and PM₁₀ mass concentrations, adjusting for premise type and dust conditions, were significantly lower in the indoor intervention group compared to the control group (PM_{2.5-intervention}/PM_2.5-control = 0.57, 95% CI: 0.47, 0.70; PM_{10-intervention}/PM_10-control = 0.59, 95% CI: 0.49, 0.71). In addition, the PM_2.5 and PM₁₀ particles of outdoor origin were significantly lower in the intervention vs. the control group (PM_2.5 infiltration intervention-to-control ratio: 0.49, 95% CI: 0.42, 0.58; PM₁₀ infiltration intervention-to-control ratio: 0.68, 95% CI: 0.52, 0.89). Our findings suggest that the use of air purifiers alongside decreased ventilation measures is an effective protective measure that reduces significantly indoor exposure to particles during DDS and non-DDS in high-risk population groups.

Room-Based Assessment of Mobile Air Cleaning Devices Using a Bioaerosol Challenge

Introduction

The widespread transmission of the SARS-CoV-2 virus has increased scientific and societal interest in air cleaning technologies, and their potential to mitigate the airborne spread of microorganisms. Here we evaluate room scale use of five mobile air cleaning devices.

Methods

A selection of air cleaners, containing high efficiency filtration, was tested using an airborne bacteriophage challenge. Assessments of bioaerosol removal efficacy were undertaken using a decay measurement approach over 3 h, with air cleaner performance compared with bioaerosol decay rate without an air cleaner in the sealed test room. Evidence of chemical by-product emission was also checked, as were total particle counts.

Results

Bioaerosol reduction, exceeding natural decay, was observed for all air cleaners. Reductions ranged between devices from <2-log per m³ room air for the least effective, to a >5-log reduction for the most efficacious systems. One system generated detectable ozone within the sealed test room, but ozone was undetectable when the system was run in a normally ventilated room. Total particulate air removal trends aligned with measured airborne bacteriophage decline.

Discussion

Air cleaner performance differed, and this could relate to individual air cleaner flow specifications as well as test room conditions, such as air mixing during testing. However, measurable reductions in bioaerosols, beyond natural airborne decay rate, were observed.

Conclusion

Under the described test conditions, air cleaners containing high efficiency filtration significantly reduced bioaerosol levels. The best performing air cleaners could be investigated further with improved assay sensitivity, to enable measurement of lower residual levels of bioaerosols.

Portable HEPA filtration successfully augments natural-ventilation-mediated airborne particle clearance in a legacy design hospital ward

As the severe acute respiratory syndrome coronavirus-2 pandemic has proceeded, ventilation has been recognized increasingly as an important tool in infection control. Many hospitals in Ireland and the UK do not have mechanical ventilation and depend on natural ventilation. The effectiveness of natural ventilation varies with atmospheric conditions and building design. In a challenge test of a legacy design ward, this study showed that portable air filtration significantly increased the clearance of pollutant aerosols of respirable size compared with natural ventilation, and reduced spatial variation in particle persistence. A combination of natural ventilation and portable air filtration is significantly more effective for particle clearance than either intervention alone.

Improved Recovery of Captured Airborne Bacteria and Viruses with Liquid-Coated Air Filters

The COVID-19 pandemic has revealed the importance of the detection of airborne pathogens. Here, we present composite air filters featuring a bioinspired liquid coating that facilitates the removal of captured aerosolized bacteria and viruses for further analysis. We tested three types of air filters: commercial polytetrafluoroethylene (PTFE), which is well known for creating stable liquid coatings, commercial high-efficiency particulate air (HEPA) filters, which are widely used, and in-house-manufactured cellulose nanofiber mats (CNFMs), which are made from sustainable materials. All filters were coated with omniphobic fluorinated liquid to maximize the release of pathogens. We found that coating both the PTFE and HEPA filters with liquid improved the rate at which Escherichia coli was recovered using a physical removal process compared to uncoated controls. Notably, the coated HEPA filters also increased the total number of recovered cells by 57%. Coating the CNFM filters did not improve either the rate of release or the total number of captured cells. The most promising materials, the liquid-coated HEPA, filters were then evaluated for their ability to facilitate the removal of pathogenic viruses via a chemical removal process. Recovery of infectious JC polyomavirus, a nonenveloped virus that attacks the central nervous system, was increased by 92% over uncoated controls; however, there was no significant difference in the total amount of genomic material recovered compared to that of controls. In contrast, significantly more genomic material was recovered for SARS-CoV-2, the airborne, enveloped virus, which causes COVID-19, from liquid-coated filters. Although the amount of infectious SARS-CoV-2 recovered was 58% higher, these results were not significantly different from uncoated filters due to high variability. These results suggest that the efficient recovery of airborne pathogens from liquid-coated filters could improve air sampling efforts, enhancing biosurveillance and global pathogen early warning.

Efficacy of HEPA Air Cleaner on Improving Indoor Particulate Matter 2.5 Concentration

High-efficiency particulate air (HEPA) filters is a potential tool used to remove fine particles and improve indoor air quality. This study aims to analyze the real-world efficacy of portable HEPA air cleaners in a household environment. Laser light dispersion PM_2.5 sensors are used to continuously monitor the indoor and outdoor PM_2.5 level before and after HEPA air cleaner filtration. Overall, HEPA air cleaners significantly reduce the indoor PM_2.5 level (33.5 ± 10.3 vs. 17.2 ± 10.7 µg/m³, mean difference (MD) = -16.3 µg/m³, p < 0.001) and indoor/outdoor PM_2.5% (76.3 ± 16.8 vs. 38.6 ± 19.8%, MD = -37.7%, p < 0.001). The efficacy to reduce PM_2.5 is strongest in three machines with medium-flow setting group (indoor PM_2.5 MD: -26.5 µg/m³, indoor/outdoor PM_2.5 percentage MD: -56.4%). Multiple linear regression demonstrates that outdoor PM_2.5, machine number, airflow speed, and window ventilation are significant factors associated with indoor PM_2.5 concentrations (R = 0.879) and percentage of the indoor/outdoor PM_2.5 ratio (R = 0.808). HEPA air cleaners can effectively improve indoor PM_2.5 air pollution. Adequate air cleaner machine numbers, appropriate airflow, and window ventilation limitations are important to achieve the best efficacy of the HEPA air cleaner.

HEPA filters for airliner cabins: State of the art and future development

The airliner cabin environment is very important to the health of passengers and crew members, and the use of high-efficiency particulate air (HEPA) filters for recirculated air in the environmental control systems (ECS) is essential for the removal of airborne particles such as SARS CoV-2 aerosols. A HEPA filter should be high efficiency, low-pressure drop, high dust-holding capacity (DHC), lightweight, and strong for use in aircraft. We conducted an experimental study on 23 HEPA filters with glass fiber media that are used in different commercial airliner models. The tested filters had a median filtration efficiency of >99.97% for particles with a diameter of 0.3-0.5 μm, a pressure drop of 134-412 Pa at rated airflow rate, and a DHC of 32.2-37.0 g/m² . The use of nanofiber media instead of glass fiber media can reduce the pressure drop by 66.4%-94.3% and significantly increase the quality factor by analysis of literature data. The disadvantages of poor fire resistance and small DHC can be overcome by the use of flame-retardant polymers and fiber structural design. As a new lightweight and environmentally friendly filter material, nanofiber media could be used as air filters in ECS in the future.

Portable HEPA Purifiers to Eliminate Airborne SARS-CoV-2: A Systematic Review

OBJECTIVE

Current epidemiologic predictions of COVID-19 suggest that SARS-CoV-2 mitigation strategies must be implemented long-term. In-office aerosol-generating procedures pose a risk to staff and patients while necessitating examination room shutdown to allow aerosol decontamination by indwelling ventilation. This review summarizes the current state of knowledge on portable high-efficiency particulate air (HEPA) purifiers' effectiveness in eliminating airborne SARS-CoV-2 from indoor environments.

DATA SOURCES

Medline, Embase, Cochrane Databases, and the World Health Organization's COVID-19 Global Literature on Coronavirus Disease.

REVIEW METHODS

Data sources were systematically searched for original English-language published studies indexed up to January 14, 2021 per the following search strategy: ("HEPA" OR "High-efficiency" OR "High-efficiency particulate air" OR "Efficiency particulate" OR "Purifier" OR "Filter" OR "Cleaner" OR "Filtration") AND ("COVID" OR "COVID-19" OR "SARS-CoV-2" OR "Coronavirus"). Additional relevant studies were identified by searching the reference lists of included articles.

RESULTS

Eleven published studies have evaluated the effectiveness of portable HEPA purifiers in eliminating airborne SARS-CoV-2 with relevantly sized surrogate particles. Ten studies evaluated aerosols and submicron particles similar in size to SARS-CoV-2 virions. In all studies, portable HEPA purifiers were able to significantly reduce airborne SARS-CoV-2-surrogate particles. The addition of portable HEPA purifiers augmented other decontamination strategies such as ventilation.

CONCLUSION

Experimental studies provide evidence for portable HEPA purifiers' potential to eliminate airborne SARS-CoV-2 and augment primary decontamination strategies such as ventilation. Based on filtration rates, additional air exchanges provided by portable HEPA purifiers may be calculated and room shutdown times potentially reduced after aerosol-generating procedures.

Can Public Spaces Effectively Be Used as Cleaner Indoor Air Shelters during Extreme Smoke Events?

During extreme air pollution events, such as bushfires, public health agencies often recommend that vulnerable individuals visit a nearby public building with central air conditioning to reduce their exposure to smoke. However, there is limited evidence that these "cleaner indoor air shelters" reduce exposure or health risks. We quantified the impact of a "cleaner indoor air shelter" in a public library in Port Macquarie, NSW, Australia when concentrations of fine particulate matter (PM_2.5) were elevated during a local peat fire and nearby bushfires. Specifically, we evaluated the air quality improvements with central air conditioning only and with the use of portable high efficiency particulate air (HEPA) filter air cleaners. We measured PM_2.5 from August 2019 until February 2020 by deploying pairs of low-cost PM_2.5 sensors (i) inside the main library, (ii) in a smaller media room inside the library, (iii) outside the library, and (iv) co-located with regulatory monitors located in the town. We operated two HEPA cleaners in the media room from August until October 2019. We quantified the infiltration efficiency of outdoor PM_2.5 concentrations, defined as the fraction of the outdoor PM_2.5 concentration that penetrates indoors and remains suspended, as well as the additional effect of HEPA cleaners on PM_2.5 concentrations. The infiltration efficiency of outdoor PM_2.5 into the air-conditioned main library was 30%, meaning that compared to the PM_2.5 concentration outdoors, the concentrations of outdoor-generated PM_2.5 indoors were reduced by 70%. In the media room, when the HEPA cleaners were operating, PM_2.5 concentrations were reduced further with a PM_2.5 infiltration efficiency of 17%. A carefully selected air-conditioned public building could be used as a cleaner indoor air shelter during episodes of elevated smoke emissions. Further improvements in indoor air quality within the building can be achieved by operating appropriately sized HEPA cleaners.

Feasibility Assessment of the Let's Walk Programme (CAMINEM): Exercise Training and Health Promotion in Primary Health-Care Settings

Exercise is related to many individual health outcomes but impact evaluations of exercise programmes are seldom conducted. The purpose of the study is to evaluate the feasibility of an exercise prescription intervention in primary health-care settings (CAMINEM Programme) located in two socially disadvantaged neighbourhoods. The CAMINEM was a pragmatic-driven intervention with opportunistic recruitment. It followed the 5As framework for health promotion and also the exercise training principles. Feasibility was evaluated using the RE-AIM framework (Reach, Effectiveness, Adoption, Implementation, and Maintenance). Patients with non-communicable chronic diseases participated in a 12-month home-based moderate-intensity exercise program, counselled by exercise physiologists. Participants were grouped according to their physical activity behaviour at baseline and 6-month adherence. CAMINEM reached 1.49% (n = 229) of the eligible population (N = 15374) and included a final sample of 178. Health outcomes for adhered participants followed positive patterns. Non-adhered participants visited their practitioner more compared to adhered participants. Thirty-three practitioners (40%) referred patients. Nurses referred four times more than physicians (81% and 19% respectively). The delivery of exercise prescriptions proved to be easy to complete and record by participants as well as easy to monitor and adjust by the exercise physiologists. One out of four participants adhered during the 12-month intervention. This intervention has been feasible in primary care in Catalonia, Spain, to safely prescribe home-based exercise for several conditions.

Effects of mechanical ventilation and portable air cleaner on aerosol removal from dental treatment rooms

Objectives

To evaluate the mechanical ventilation rates of dental treatment rooms and assess the effectiveness of aerosol removal by mechanical ventilation and a portable air cleaner (PAC) with a high-efficiency particulate air (HEPA) filter.

Methods

Volumetric airflow were measured to assess air change rate per hour by ventilation (ACH_vent). Equivalent ventilation provided by the PAC (ACH_pac) was calculated based on its clean air delivery rate. Concentrations of 0.3, 0.5 and 1.0 μm aerosol particles were measured in 10 dental treatment rooms with various ventilation rates at baseline, after 5-min of incense burn, and after 30-min of observation with and without the PAC or ventilation system in operation. Velocities of aerosol removal were assessed by concentration decay constants for the 0.3 μm particles with ventilation alone (K_n) and with ventilation and PAC (K_n+pac), and by times needed to reach 95 % and 100 % removal of accumulated aerosol particles.

Results

ACH_vent varied from 3 to 45. K_n and K_n+pac were correlated with ACH_vent (r = 0.90) and combined ACH_total (r = 0.81), respectively. Accumulated aerosol particles could not be removed by ventilation alone within 30-min in rooms with ACH_vent<15. PAC reduced aerosol accumulation and accelerated aerosol removal, and accumulated aerosols could be completely removed in 4 to 12-min by ventilation combined with PAC. Effectiveness of the PAC was especially prominent in rooms with poor ventilation. Added benefit of PAC in aerosol removal was inversely correlated with ACH_vent.

Conclusions

Aerosol accumulation may occur in dental treatment rooms with poor ventilation. Addition of PAC with a HEPA filter significantly reduced aerosol accumulation and accelerated aerosol removal.

Clinical significance

Addition of PAC with a HEPA filter improves aerosol removal in rooms with low ventilation rates.

Individual- and Household-Level Interventions to Reduce Air Pollution Exposures and Health Risks: a Review of the Recent Literature

PURPOSE OF REVIEW

We reviewed recent peer-reviewed literature on three categories of individual- and household-level interventions against air pollution: air purifiers, facemasks, and behavior change.

RECENT FINDINGS

High-efficiency particulate air/arresting (HEPA) filter air purifier use over days to weeks can substantially reduce fine particulate matter (PM2.5) concentrations indoors and improve subclinical cardiopulmonary health. Modeling studies suggest that the population-level benefits of HEPA filter air purification would often exceed costs. Well-fitting N95 and equivalent respirators can reduce PM2.5 exposure, with several randomized crossover studies also reporting improvements in subclinical cardiovascular health. The health benefits of other types of face coverings have not been tested and their effectiveness in reducing exposure is highly variable, depends largely on fit, and is unrelated to cost. Behavior modifications may reduce exposure, but there has been little research on health impacts. There is now substantial evidence that HEPA filter air purifiers reduce indoor PM2.5 concentrations and improve subclinical health indicators. As a result, their use is being recommended by a growing number of government and public health organizations. Several studies have also reported subclinical cardiovascular health benefits from well-fitting respirators, while evidence of health benefits from other types of facemasks and behavior changes remains very limited. In situations when emissions cannot be controlled at the source, such as during forest fires, individual- or household-level interventions may be the primary option. In most cases, however, such interventions should be supplemental to emission reduction efforts that benefit entire communities.

How efficiently can HEPA purifiers remove priority fine and ultrafine particles from indoor air?

More than 1 million premature deaths in Asia annually are estimated to be associated with indoor air quality. HEPA (high-efficiency particulate air) filter air purifiers (APs) are widely used in urban Chinese residences by the growing middle class, as public awareness of air pollution increases. Currently, understanding of how particle size affects particle removal is inconsistent, and the rate at which different particle types are removed remains largely unknown. Therefore, this investigation aimed to determine the relationship between particle size and the removal efficiency of particles, and how efficiently ambient air is filtered compared to particle types which are typically used in standard tests (tobacco smoke, dust and pollen). Three of the most popular AP models in China were tested in China's largest indoor controlled chamber laboratory and the removal efficiencies of particles in the 18-514 nm range were identified. Each AP had a distinct profile of removal efficiency against particle size, but the three APs shared similarities in performance, with removal efficiency consistently lowest at 200-250 nm. This size fraction is important in an exposure context as these particles are abundant in ambient air in mega-cities, can penetrate through building shells effectively, remain airborne for long periods of time and can penetrate the deepest areas of the lungs. Ambient air particles were removed at a similar rate to test particles; this confirms that the Association of Home Appliance Manufacturers' (AHAM) standards are a suitable proxy for "real world" performance.

Air filtration and SARS-CoV-2

Air filtration in various implementations has become a critical intervention in managing the spread of coronavirus disease 2019 (COVID-19). However, the proper deployment of air filtration has been hampered by an insufficient understanding of its principles. These misconceptions have led to uncertainty about the effectiveness of air filtration at arresting potentially infectious aerosol particles. A correct understanding of how air filtration works is critical for further decision-making regarding its use in managing the spread of COVID-19. The issue is significant because recent evidence has shown that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can remain airborne longer and travel farther than anticipated earlier in the COVID-19 pandemic, albeit with diminishing concentrations and viability. While SARS-CoV-2 virions are around 60-140 nm in diameter, larger respiratory droplets and air pollution particles (>1 µm) have been found to harbor the virions. Removing particles that could carry SARS-CoV-2 from the air is possible using air filtration, which relies on the natural or mechanical movement of air. Among various types of air filters, high-efficiency particle arrestance (HEPA) filters have been recommended. Other types of filters are less or more effective and, correspondingly, are easier or harder to move air through. The use of masks, respirators, air filtration modules, and other dedicated equipment is an essential intervention in the management of COVID-19 spread. It is critical to consider the mechanisms of air filtration and to understand how aerosol particles containing SARS-CoV-2 virions interact with filter materials to determine the best practices for the use of air filtration to reduce the spread of COVID-19.

Make Them Move: Understanding Visitors' Sedentary Behavior in Protected Natural Areas. A Case Study in Spain

BACKGROUND

Protected areas are important attractions for promoting healthy life habits. Consequently, to date, a number of studies have examined the association between visitors' characteristics and physical activities. However, little is known about the specific users inclined exclusively to have sedentary behavior during a visit. Thus, using the Alt Pirineu Natural Park (Spain) as a case study, the aim of this study is to determine the influence of sociodemographic, trip, motivational, and opinion descriptors on the likelihood of participating in sedentary behavior while visiting a protected natural area.

METHODS

The data used were randomly collected from visitors through an onsite structured questionnaire (N = 628).

RESULTS

Metabolic equivalent consumption was used to empirically distinguish the sedentary (22.6%) from the active (77.4%) visitor groups. A logistic regression analysis indicated that the trip and motivational descriptors explained the highest degree of the overall variation in reporting sedentary behavior.

CONCLUSION

The study contributed to documenting the information about visitors' behavior in protected areas, and the findings may aid park managers in developing effective management strategies for promoting and enhancing physical activity in protected natural areas.

Effectiveness of Airborne Fungi Removal by using a HEPA Air Purifier Fan in Houses

Few studies have evaluated the performance of air purifiers in removing airborne fungi in houses. Here, we evaluated the ability of a HEPA air purifier fan to remove airborne fungi in six houses in Japan. In each house, the number of airborne fungi decreased more rapidly when the air purifier fan was on (test measurement) than when it was off (control) , demonstrating its ability to decrease the fungal concentration. The number of airborne fungi decreased between 1.5 and 6 times faster when the air purifier fan was on than when it was off (spontaneous decrease) . Clean air change rates, calculated from measurements taken 15 min after the test equipment operation began, ranged from 2.9 to 5.4 (h^-1) , indicating adequate air cleaning. One of the six test houses contained a much greater concentration of airborne fungi than the standard set by the Architectural Institute of Japan. When the air purifier fan was operated in the house, the indoor/outdoor (I/O) ratio decreased from 77.5, equating to a fungal concentration of 53,000 cfu/m³ at 0 min to 0.72 or 620 cfu/m³ after 45 min, which is below the standard. This reduction clearly demonstrated the antifungal effect of the air purifier fan.

The effect of portable HEPA filter air cleaner use during pregnancy on fetal growth: The UGAAR randomized controlled trial

BACKGROUND

Fine particulate matter (PM_2.5) exposure may impair fetal growth.

AIMS/OBJECTIVES

Our aim was to assess the effect of portable high efficiency particulate air (HEPA) filter air cleaner use during pregnancy on fetal growth.

METHODS

The Ulaanbaatar Gestation and Air Pollution Research (UGAAR) study is a single-blind randomized controlled trial conducted in Ulaanbaatar, Mongolia. Non-smoking pregnant women recruited at ≤18 weeks gestation were randomized to an intervention (1-2 air cleaners in homes from early pregnancy until childbirth) or control (no air cleaners) group. Participants were not blinded to their intervention status. Demographic, health, and birth outcome data were obtained via questionnaires and clinic records. We used unadjusted linear and logistic regression and time-to-event analysis to evaluate the intervention. Our primary outcome was birth weight. Secondary outcomes were gestational age-adjusted birth weight, birth length, head circumference, gestational age at birth, and small for gestational age. The study is registered at ClinicalTrials.gov (NCT01741051).

RESULTS

We recruited 540 participants (272 control and 268 intervention) from January 9, 2014 to May 1, 2015. There were 465 live births and 28 losses to follow up. We previously reported a 29% (95% CI: 21, 37%) reduction in indoor PM_2.5 concentrations with portable HEPA filter air cleaner use. The median (25th, 75th percentile) birth weights for control and intervention participants were 3450 g (3150, 3800 g) and 3550 g (3200, 3800 g), respectively (p = 0.34). The intervention was not associated with birth weight (18 g; 95% CI: -84, 120 g), but in a pre-specified subgroup analysis of 429 term births the intervention was associated with an 85 g (95% CI: 3, 167 g) increase in mean birth weight.

CONCLUSIONS

HEPA filter air cleaner use in a high pollution setting was associated with greater birth weight only among babies born at term.

Assessing the Influence of Visitors' Sociodemographic and Trip Characteristics on Physical Activity Intensities in Alt Pirineu Natural Park, Spain

BACKGROUND

Protected natural areas provide a promising opportunity for improving healthy life habits through engagement in a variety of physical activities (PAs). As visitors to protected natural areas do not behave as a homogenous group, it is necessary to better understand the association between their characteristics and the level of activities engaged in. Using Alt Pirineu Natural Park (Spain) as a case study, the purpose of this work is to examine the influence of visitors' sociodemographic and trip characteristics on the likelihood of the visitors engaging in distinct PA intensities.

METHODS

Data were systematically collected from visitors (N = 1427) by means of self-administered questionnaires using a face-to-face approach.

RESULTS

To identify distinct groups of PA intensities reported activities of visitors were classified following the Compendium of PA and metabolic equivalent consumption. Three groups were identified and labeled as follows: light PA group (16.8%), moderate PA group (63.9%), and vigorous PA group (19.3%). A logistic regression analysis indicated that the capacity of selected descriptors to predict group membership was positively associated with the increment in PA intensities.

CONCLUSION

The study findings may aid park managers in developing effective management strategies for promoting health-enhancing PA in protected natural areas.

Prevalence and socioeconomic determinants of leisure time physical activity among Polish farmers

INTRODUCTION AND OBJECTIVE

The aim of this study is to evaluate the leisure time physical activity of Polish farmers in the context of meeting health-related recommendations, and to diagnose the social and economic determinants. The analysis concerned leisure and transportation activities of various intensity and sedentary time.

MATERIAL AND METHODS

Farmers (n=153) aged over 18 were selected from a representative sample of Polish society (n=2039). In order to evaluate LTPA, the long version of the IPAQ was used. Statistically significant differences between the variables were tested using non-parametric tests. The relationship between the amount of exercise recommended by the WHO and studied socio-demographic criteria was assessed using log-linear analysis.

RESULTS

The WHO health recommendations were met by 33.3% of farmers. Shares in LTPA (19.1%) and transportation (19.2%) significantly increased the chance of achieving these norms (OR=12.54 and 0.07, respectively). Along with age (≥40 years) and income (≥3000 PLN/Є750) of Polish farmers, the risk of insufficient physical activity increased. Average MET-min/week for LTPA was 299.8±583.4 and transportation - 521.2±1973.9. The average time of sitting during working days was 4.4±2.9, while it was 4.5±3.2 hrs/day during weekends.

CONCLUSIONS

Health-promoting changes are necessary among Polish farmers, including an increase in the awareness of health benefits and the necessity of undertaking physically active ways of spending leisure time. It seems to be a legitimate action to develop a mini-tourist trail in the rural environment as a means of promoting physical activity also among women aged over 40, and from lower income groups, who are especially threatened by inactivity.

The effect of portable HEPA filter air cleaners on indoor PM2.5 concentrations and second hand tobacco smoke exposure among pregnant women in Ulaanbaatar, Mongolia: The UGAAR randomized controlled trial

BACKGROUND

Portable HEPA filter air cleaners can reduce indoor fine particulate matter (PM_2.5), but their use has not been adequately evaluated in high pollution settings. We assessed air cleaner effectiveness in reducing indoor residential PM_2.5 and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia.

METHODS

We randomized 540 participants to an intervention group receiving 1 or 2 HEPA filter air cleaners or a control group receiving no air cleaners. We followed 259 intervention and 253 control participants to the end of pregnancy. We measured one-week indoor residential PM_2.5 concentrations in early (~11weeks gestation) and late (~31weeks gestation) pregnancy and collected outdoor PM_2.5 data from centrally-located government monitors. We assessed blood cadmium in late pregnancy. Hair nicotine was quantified in a subset (n=125) to evaluate blood cadmium as a biomarker of SHS exposure. We evaluated air cleaner effectiveness using mixed effects and multiple linear regression models and used stratified models and interaction terms to evaluate potential modifiers of effectiveness.

RESULTS

The overall geometric mean (GM) one-week outdoor PM_2.5 concentration was 47.9μg/m³ (95% CI: 44.6, 51.6μg/m³), with highest concentrations in winter (118.0μg/m³; 110.4, 126.2μg/m³). One-week indoor and outdoor PM_2.5 concentrations were correlated (r=0.69). Indoor PM_2.5 concentrations were 29% (21, 37%) lower in intervention versus control apartments, with GMs of 17.3μg/m³ (15.8, 18.8μg/m³) and 24.5μg/m³ (22.2, 27.0μg/m³), respectively. Air cleaner effectiveness was greater when air cleaners were first deployed (40%; 31, 48%) than after approximately five months of use (15%; 0, 27%). Blood cadmium concentrations were 14% (4, 23%) lower among intervention participants, likely due to reduced SHS exposure.

CONCLUSIONS

Portable HEPA filter air cleaners can lower indoor PM_2.5 concentrations and SHS exposures in highly polluted settings.

Lessons from in-home air filtration intervention trials to reduce urban ultrafine particle number concentrations

BACKGROUND

Exposure to airborne ultrafine particle (UFP; <100 nm in aerodynamic diameter) is an emerging public health problem. Nevertheless, the benefit of using high efficiency particulate arrestance (HEPA) filtration to reduce UFP concentrations in homes is not yet clear.

METHODS

We conducted a randomized crossover study of HEPA filtration without a washout period in 23 homes of low-income Puerto Ricans in Boston and Chelsea, MA (USA). Most participants were female, older adults who were overweight or obese. Particle number concentrations (PNC, a proxy for UFP) were measured indoors and outdoors at each home continuously for six weeks. Homes received both HEPA filtration and sham filtration for three weeks each in random order.

RESULTS

Median PNC under HEPA filtration was 50-85% lower compared to sham filtration in most homes, but we found no benefit in terms of reduced inflammation; associations between hsCRP, IL-6, or TNFRII in blood samples and indoor PNC were inverse and not statistically significant.

CONCLUSIONS

Limitations to our study design likely contributed to our findings. Limitations included carry-over effects, a population that may have been relatively unresponsive to UFP, reduction in PNC even during sham filtration that limited differences between HEPA and sham filtration, window opening by participants, and lack of fine-grained (room-specific) participant time-activity information. Our approach was similar to other recent HEPA intervention studies of particulate matter exposure and cardiovascular risk, suggesting that there is a need for better study designs.

Lessons from in-home air filtration intervention trials to reduce urban ultrafine particle number concentrations

BACKGROUND

Exposure to airborne ultrafine particle (UFP; <100 nm in aerodynamic diameter) is an emerging public health problem. Nevertheless, the benefit of using high efficiency particulate arrestance (HEPA) filtration to reduce UFP concentrations in homes is not yet clear.

METHODS

We conducted a randomized crossover study of HEPA filtration without a washout period in 23 homes of low-income Puerto Ricans in Boston and Chelsea, MA (USA). Most participants were female, older adults who were overweight or obese. Particle number concentrations (PNC, a proxy for UFP) were measured indoors and outdoors at each home continuously for six weeks. Homes received both HEPA filtration and sham filtration for three weeks each in random order.

RESULTS

Median PNC under HEPA filtration was 50-85% lower compared to sham filtration in most homes, but we found no benefit in terms of reduced inflammation; associations between hsCRP, IL-6, or TNFRII in blood samples and indoor PNC were inverse and not statistically significant.

CONCLUSIONS

Limitations to our study design likely contributed to our findings. Limitations included carry-over effects, a population that may have been relatively unresponsive to UFP, reduction in PNC even during sham filtration that limited differences between HEPA and sham filtration, window opening by participants, and lack of fine-grained (room-specific) participant time-activity information. Our approach was similar to other recent HEPA intervention studies of particulate matter exposure and cardiovascular risk, suggesting that there is a need for better study designs.

Enhancing indoor air quality -The air filter advantage

Air pollution has become the world's single biggest environmental health risk, linked to around 7 million deaths in 2012 according to a recent World Health Organisation (WHO) report. The new data further reveals a stronger link between, indoor and outdoor air pollution exposure and cardiovascular diseases, such as strokes and ischemic heart disease, as well as between air pollution and cancer. The role of air pollution in the development of respiratory diseases, including acute respiratory infections and chronic obstructive pulmonary diseases, is well known. While both indoor and outdoor pollution affect health, recent statistics on the impact of household indoor pollutants (HAP) is alarming. The WHO factsheet on HAP and health states that 3.8 million premature deaths annually - including stroke, ischemic heart disease, chronic obstructive pulmonary disease (COPD) and lung cancer are attributed to exposure to household air pollution. Use of air cleaners and filters are one of the suggested strategies to improve indoor air quality. This review discusses the impact of air pollutants with special focus on indoor air pollutants and the benefits of air filters in improving indoor air quality.

A Randomized Cross-over Air Filtration Intervention Trial for Reducing Cardiovascular Health Risks in Residents of Public Housing near a Highway

Exposure to traffic-generated ultrafine particles (UFP; particles <100 nm) is likely a risk factor for cardiovascular disease. We conducted a trial of high-efficiency particulate arrestance (HEPA) filtration in public housing near a highway. Twenty residents in 19 apartments living <200 m from the highway participated in a randomized, double-blind crossover trial. A HEPA filter unit and a particle counter (measuring particle number concentration (PNC), a proxy for UFP) were installed in living rooms. Participants were exposed to filtered air for 21 days and unfiltered air for 21 days. Blood samples were collected and blood pressure measured at days 0, 21 and 42 after a 12-hour fasting period. Plasma was analyzed for high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), tumor necrosis factor alpha-receptor II (TNF-RII) and fibrinogen. PNC reductions ranging from 21% to 68% were recorded in 15 of the apartments. We observed no significant differences in blood pressure or three of the four biomarkers (hsCRP, fibrinogen, and TNF-RII) measured in participants after 21-day exposure to HEPA-filtered air compared to measurements after 21-day exposure to sham-filtered air. In contrast, IL-6 concentrations were significantly higher following HEPA filtration (0.668 pg/mL; CI = 0.465-0.959) compared to sham filtration. Likewise, PNC adjusted for time activity were associated with increasing IL-6 in 14- and 21-day moving averages, and PNC was associated with decreasing blood pressure in Lags 0, 1 and 2, and in a 3-day moving average. These negative associations were unexpected and could be due to a combination of factors including exposure misclassification, unsuccessful randomization (i.e., IL-6 and use of anti-inflammatory medicines), or uncontrolled confounding. Studies with greater reduction in UFP levels and larger sample sizes are needed. There also needs to be more complete assessment of resident time activity and of outdoor vs. indoor source contributions to UFP exposure. HEPA filtration remains a promising, but not fully realized intervention.

Use of Free-standing Filters in an Asthma Intervention Study

This study characterizes the use of HEPA air filters provided to 89 households participating in an intervention study investigating the respiratory health of children with asthma. Freestanding filters were placed in the child's bedroom and monitored continuously for nearly a year in each household. Filter use was significantly affected by study phase, season and monitoring week. During the "intensive" weeks when a community education worker and a field technician visited the household, the use rate averaged 70±33%. During season-long "non-intensive" periods between seasonal visits, use dropped to 34±30%. Filter use rapidly decreased during the 3 to 4 weeks following each intensive, was slightly higher in spring, summer, and in the evening and at night when the child was likely to be home, although households did not follow consistent diurnal patterns. While participants expressed an understanding of the benefits of filter use and reported good experiences with them, use rates were low, particularly during unobserved non-intensive periods. The provision of freestanding air filters to individuals or households must be considered an active intervention that requires monitoring and evaluation, otherwise unknown and unexpected patterns of filter use may alter and possibly bias results due to exposure misclassification.

Trace elements (copper, zinc, selenium and molybdenum) as markers in oral sub mucous fibrosis and oral squamous cell carcinoma

Oral cancer is a major cause of cancer morbidity and mortality worldwide and is prevalent in most areas where tobacco related practices are observed. Essential elements play a role in many biochemical reactions as a micro-source and there is growing evidence that their concentrations are altered on the onset and progress of malignant disease. In this study the levels of copper (Cu), zinc (Zn), selenium (Se) and molybdenum (Mo) in serum of patients with oral sub mucous fibrosis (OSMF) (n = 30) and oral squamous cell carcinoma (OSCC) (n = 30); were determined and the alterations of these critical parameters were analyzed in comparison with controls (n = 30) to identify predictors amongst these parameters for disease occurrence and progression. The serum Cu and Zn were established using Flame Atomic Absorption Spectrometry. Serum estimation of Se and Mo was done by graphite furnace atomic absorption spectrometry (GFAAS). Data analysis revealed a marked, progressive and significant increase in Cu levels in precancer (OSMF) and cancer (OSCC) groups as compared to the normal group. The level of Zn in serum was slightly elevated in OSMF and OSCC though not statistically significant. Cu/Zn ratio was slightly but not significantly elevated. Serum levels of Se and Mo were significantly decreased in the precancer and cancer groups as compared to the normals.

Epidemiological and phylogenetic analysis of institutional mouse parvoviruses

Mouse parvoviruses (MPVs) are small, single-stranded, 5 kb DNA viruses that are subclinical and endemic in many laboratory mouse colonies. MPVs cause more distinctive deleterious effects in immune-compromised or genetically-engineered mice than immuno-competent mice. At the University of Louisville (U of L), there was an unexpected increase of MPV sero-positivity for MPV infections in mouse colonies between January 2006 and February 2007, resulting in strategic husbandry changes aimed at controlling MPV spread throughout the animal facility. To investigate these MPVs, VP2 genes of seven MPVs were cloned and sequenced from eight documented incidences by PCR technology. The mutations in these VP2 genes were compared to those found at the Genbank database (NCBI; http://www.ncbi.nlm.nih.gov) and an intra-institutional phylogenetic tree for MPV infections at U of L was constructed. We discovered that the seven MPV isolates were different from those in Genbank and were not identical to each other. These MPVs were designated MPV-UL1 to 7; none of them were minute virus of mice (MVMs). Four isolates could be classified as MPV1, one was classified as MPV2, and two were defined as novel types with less than 96% and 94% homology with existing MPV types. Considering that all seven isolates had mutations in their VP2 genes and no mutations were observed in VP2 genes of MPV during a four-month time period of incubation, we concluded that all seven MPVs isolated at U of L between 2006 and 2007 probably originated from different sources. Serological survey for MPV infections verified that each MPV outbreak was controlled without further contamination within the institution.