The impact of indoor air pollution on children's health and well-being: the experts' consensus.

BACKGROUND: Pollution of the indoor environment represents a concern for human health, mainly in case of prolonged exposure such as in the case of women, children, the elderly, and the chronically ill, who spend most of their time in closed environments. MAIN BODY: The aim of the study is to organize a group of experts in order to evaluate the evidence and discuss the main risk factors concerning indoor air and the impact on human health as well as challenging factors regarding preventive strategies to reduce pollution. The experts highlighted the main risk factors concerning indoor air, including poor ventilation, climatic conditions, chemical substances, and socio-economic status. They discussed the impact on human health in terms of mortality and morbidity, as well as challenging factors regarding preventive strategies to reduce pollution. CONCLUSION: The experts identified strategies that can be reinforced to reduce indoor pollution and prevent negative consequences on human health at national and local levels.

Optimizing the Indoor Air Quality in Historical Buildings: Strategies for Environmental Improvement and Public Health Enhancement.

The endeavor to maintain and enhance the indoor air quality (IAQ) in historical buildings transcends the traditional boundaries of cultural heritage preservation, emerging as a pivotal public health concern [...].

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.

Indoor Air Sources of Outdoor Air Pollution: Health Consequences, Policy, and Recommendations: An Official American Thoracic Society Workshop Report.

Indoor sources of air pollution worsen indoor and outdoor air quality. Thus, identifying and reducing indoor pollutant sources would decrease both indoor and outdoor air pollution, benefit public health, and help address the climate crisis. As outdoor sources come under regulatory control, unregulated indoor sources become a rising percentage of the problem. This American Thoracic Society workshop was convened in 2022 to evaluate this increasing proportion of indoor contributions to outdoor air quality. The workshop was conducted by physicians and scientists, including atmospheric and aerosol scientists, environmental engineers, toxicologists, epidemiologists, regulatory policy experts, and pediatric and adult pulmonologists. Presentations and discussion sessions were centered on 1) the generation and migration of pollutants from indoors to outdoors, 2) the sources and circumstances representing the greatest threat, and 3) effective remedies to reduce the health burden of indoor sources of air pollution. The scope of the workshop was residential and commercial sources of indoor air pollution in the United States. Topics included wood burning, natural gas, cooking, evaporative volatile organic compounds, source apportionment, and regulatory policy. The workshop concluded that indoor sources of air pollution are significant contributors to outdoor air quality and that source control and filtration are the most effective measures to reduce indoor contributions to outdoor air. Interventions should prioritize environmental justice: Households of lower socioeconomic status have higher concentrations of indoor air pollutants from both indoor and outdoor sources. We identify research priorities, potential health benefits, and mitigation actions to consider (e.g., switching from natural gas to electric stoves and transitioning to scent-free consumer products). The workshop committee emphasizes the benefits of combustion-free homes and businesses and recommends economic, legislative, and education strategies aimed at achieving this goal.

Zonal demand-controlled ventilation strategy to minimize infection probability and energy consumption: A coordinated control based on occupant detection.

Due to the outbreak of COVID-19, an increased risk of airborne transmission has been experienced in buildings, particularly in confined public places. The need for ventilation as a means of infection prevention has become more pronounced given that some basic precautions (like wearing masks) are no longer mandatory. However, ventilating the space as a whole (e.g., using a unified ventilation rate) may lead to situations where there is either insufficient or excessive ventilation in localized areas, potentially resulting in localized virus accumulation or large energy consumption. It is of urgent need to investigate real-time control of ventilation systems based on local demands of the occupants to strike a balance between infection risk and energy saving. In this work, a zonal demand-controlled ventilation (ZDCV) strategy was proposed to optimize the ventilation rates in sub-zones. A camera-based occupant detection method was developed to detect occupants (with eight possible locations in sub-zones denoted as 'A' to 'H'). Linear ventilation model (LVM), dimension reduction, and artificial neural network (ANN) were integrated for rapid prediction of pollutant concentrations in sub-zones with the identified occupants and ventilation rates as inputs. Coordinated ventilation effects between sub-zones were optimized to improve infection prevention and energy savings. Results showed that rapid prediction models achieved an average prediction error of 6 ppm for CO2 concentration fields compared with the simulation under different occupant scenarios (i.e., occupant locations at ABH, ABCFH, and ABCDEFH). ZDCV largely reduced the infection risk to 2.8% while improved energy-saving efficiency by 34% compared with the system using constant ventilation rate. This work can contribute to the development of building environmental control systems in terms of pollutant removal, infection prevention, and energy sustainability.

Effects of long-term indoor air purification intervention on cardiovascular health in elderly: a parallel, double-blinded randomized controlled trial in Hong Kong.

Ambient fine particulate matter (PM2.5) is a leading environmental risk factor globally, and over half of the associated disease burden are caused by cardiovascular disease. Numerous randomized controlled trials (RCT) have investigated the short-term cardiovascular benefits of indoor air purifiers (IAPs), but major knowledge gaps remain on their longer-term benefits. In this 1-year, randomized, double-blinded, parallel controlled trial of 47 elderly (ntrue-purification = 24; nsham-purification = 23) aged ≥70 years, true-purification reduced household PM2.5 levels by 28% and maintained lower exposure throughout the year compared to the sham-purification group. After 12 months of intervention, a significant reduction of diastolic blood pressure was found in the true-purification versus sham-purification group (-4.62 [95% CI: -7.28, -1.96] mmHg) compared to baseline measurement prior to the intervention, whereas systolic blood pressure showed directionally consistent but statistically non-significant effect (-2.49 [95% CI: -9.25, 4.28] mmHg). Qualitatively similar patterns of associations were observed for pulse pressure (-2.30 [95% CI: -6.57, 1.96] mmHg) and carotid intima-media thickness (-10.0% [95% CI: -24.8%, 4.7%]), but these were not statistically significant. Overall, we found suggestive evidence of cardiovascular benefits of long-term IAPs use, particularly on diastolic blood pressure. Evidence on other longer-term cardiovascular traits is less clear. Further trials with larger sample sizes and long-term follow-up are needed across diverse populations to evaluate the cardiovascular benefits of IAPs.

Mitigation strategies to reduce particulate matter concentrations in civil engineering laboratories.

In the departments of civil engineering, many experiments are conducted in laboratories for educational and research purposes. Varying degrees of respirable dust are generated as the outcome of these experiments, which could cause harm to instructors' and students' health. This study is devised to highlight the importance of indoor air quality in university laboratories. As part of the research, four different particulate matter (PM) sizes (PM1.0, PM2.5, PM4.0, and PM10) were measured during specific experiments-sieve analysis, preparation of the concrete mixture, crushing aggregate by jaw crusher, dynamic triaxial compression test, sieve analysis of silt specimen, cleaning sieve by an air compressor, and proctor compaction test-being conducted periodically in the laboratories of civil engineering departments. The measured values are mainly high compared to indoor air quality standards. Mitigation strategies were applied to reduce indoor air PM levels in the three experiments that contained the highest PM levels. The results have shown that mitigation strategies applied as control measures could make a remarkable difference in protecting instructors and civil engineering students.

Effect of spraying air freshener on particulate and volatile organic compounds in vehicles.

People in these days spend approximately 6 % of their time in a means of transport. Air fresheners are frequently used in vehicles to mask odors; however, they can cause adverse health effects such as cardiovascular disease, systemic inflammation and autonomic dysfunction. This study aimed to identify the effects of air fresheners on the concentrations of particulate and volatile organic compounds (VOCs) in different vehicle cabins. Scanning mobility and optical particle sizers were used for the particle measurements. VOCs (e.g., BTEX and d-limonene) were collected using a Tenax TA. The products were sprayed for less than a minute. The study assessed three spray products (all trigger types), vehicle size (small, medium, and large), cabin temperature (10 °C, 20 °C, and 25 °C), and in-vehicle ventilation mode (all-off, recirculation, and external inflow modes). The particle concentration increased rapidly during the 1-min spraying of the products. The proportion of nanoparticles in the front seat (67.2 % ± 2.2 %) was 11.1 % ± 2.2 % lower than that in the rear seat (75.6 % ± 2.1 %). The spray product and vehicle size did not significantly affect the particle or VOC concentrations. With an increase in the temperature of the front seat, the proportion of nanoparticles increased by 25.3 % ± 3.2 %. Moreover, the maximum total VOC concentrations (front seat: 364.3 µg/m3; back seat: 241.3 µg/m3) were observed at 20 °C. Under in-vehicle ventilation, recirculation effectively reduced the overall particle concentration within the cabin; however, the generated VOCs circulated. The external inflow proved effective in cabin air purification by reducing the total VOC concentration to 56.0-57.2 % compared with other ventilation modes. These findings provide substantial insight into the persistence of particles and the dynamics of their dispersion, thereby enabling informed decision-making for particle-related risk management.

Bauen mit Holz ­ Empfehlungen für eine gute Raumluftqualität : Mitteilung der Kommission Innenraumlufthygiene (IRK).

Wood is a sustainable and widely applicable building material. Wood products emit gaseous substances into the indoor air, which is why they should meet the same indoor air quality requirements as any other building product used indoors. The Commission on Indoor Air Hygiene (IRK) provides advice on how to ensure healthy indoor living conditions in the presence of wood products. Important requirements are the selection of low-emission woods and wood-based materials, compliance with health-related assessment standards, and a ventilation concept that is tailored to the usage and emission sources in the building. When considering these guidelines, wood and wood-based materials can be successfully used both in existing buildings and in newly constructed, airtight buildings with low energy requirements.

Indoor air pollution prevention practices and associated factors among household mothers in Olenchiti town, Oromia, Ethiopia.

INTRODUCTION: Most households in low- and middle-income countries still cook using solid fuels in poorly ventilated dwellings. Indoor air pollution causes various health problems, like pneumonia, lung cancer, stillbirth, low birth weight, impaired cognitive development, and cataracts. Nevertheless, a few evidences are available in Africa, including Ethiopia. Therefore, this study aimed to assess the level of indoor air pollution prevention practices and associated factors among household mothers in Olenchiti town, Oromia, Ethiopia. METHODS: A community-based cross-sectional study was conducted. Four hundred twenty mothers were randomly selected by systematic random sampling. Data was collected through an interview and observation checklist. The collected data entered into Epi-Info version 7.2.5 was cleaned, edited, and then exported to SPSS version 23 for analysis. Descriptive statistics were used to describe the findings. Binary logistic regression was computed to analyze the effect of each variable on the outcome variable. Model adequacy fitness was checked with the Hosmer-Lemeshow test. The multicollinearity of independent variables was checked with the variance inflation factor. Adjusted odds ratio with 95% confidence interval and P -value <0.05 was used as cutoff points to declare significance in the final model. RESULTS: The overall good practices of mothers towards the prevention of indoor air pollution was 188 (45.0%). Mothers who had under-five children (AOR = 0.49, 95%CI (0.31-0.76), mothers in grade 9-12 (AOR = 0.51, 95%CI (0.28-0.92)) were significantly associated with indoor air pollution prevention practices. CONCLUSION: The overall good practices of mothers towards indoor air pollution were low compared to different findings. Under-five children and educational status were significantly associated with indoor air pollution prevention practices in the final model. Therefore, the high school curriculums should include indoor air pollution topics.

Holistic understanding of ventilation rate in occupational health risk control.

Throughout the history of occupational health risk control, ventilation has been implemented widely as a tried-and-true method to reduce exposure intensity to airborne contaminants. Proper determination of the ventilation rate merits careful consideration when addressing concerns directed toward occupational health and indoor air quality in commercial buildings, albeit this does not translate well among the current engineering and scientific community. This article aims to facilitate a better understanding and proper determination of ventilation rates as a countermeasure for occupational health risk control. To that end, guidance is provided to select the appropriate ventilation rate for nonpandemic versus pandemic scenarios in terms of pertinent regulatory/professional codes and mathematical modeling tools. Limitations and assumptions of the models are summarized to facilitate proper application. Furthermore, the emerging DNA-based aerosol tracing technology, which helps to verify ventilation efficacy, is discussed.

Indoor air quality improvement with filtration and UV-C on mitigation of particulate matter and airborne bacteria: Monitoring and modeling.

Indoor air, especially with suspended particulate matter (PM), can be a carrier of airborne infectious pathogens. Without sufficient ventilation, airborne infectious diseases can be transmitted from one person to another. Indoor air quality (IAQ) significantly impacts people's daily lives as people spend 90% of their time indoors. An industrial-grade air cleaner prototype (filtration + ultraviolet light) was previously upgraded to clean indoor air to improve IAQ on two metrics: particulate matter (PM) and viable airborne bacteria. Previous experiments were conducted to test its removal efficiency on PM and airborne bacteria between the inlet and treated air. However, the longer-term improvement on IAQ would be more informative. Therefore, this research focused on quantifying longer-term improvement in a testing environment (poultry facility) loaded with high and variable PM and airborne bacteria concentrations. A 25-day experiment was conducted to treat indoor air using an air cleaner prototype with intermittent ON and OFF days in which PM and viable airborne bacteria were measured to quantify the treatment effect. The results showed an average of 55% reduction of total suspended particulate (TSP) concentration between OFF days (110 µg/m3) and ON days (49 µg/m3). An average of 47% reduction of total airborne viable bacteria concentrations was achieved between OFF days (∼3200 CFU/m3) and ON days (∼2000 CFU/m3). A cross-validation (CV) model was established to predict PM concentrations with five input variables, including the status of the air cleaner, time (h), ambient temperature, indoor relative humidity, and day of the week to help simulate the air-cleaning effect of this prototype. The model can approximately predict the air quality trend, and future improvements may be made to improve its accuracy.

Association of cigarette excise taxes and clean indoor air laws with change in smoking behavior in the United States: a Markov modeling analysis.

The rates of cigarette smoking in the United States have declined over the past few decades in parallel with increases in cigarette taxes and introduction of more stringent clean indoor air laws. Few longitudinal studies have examined association of taxes and clean indoor air policies with change in smoking nationally. This study examined the association of state and local cigarette taxes and clean indoor laws with change in smoking status of 18,499 adult participants of the longitudinal 2010-2011 Tobacco Use Supplement of the Current Population Survey over a period of 1 year. Every $1 increase in cigarette excise taxes was associated with 36% higher likelihood of stopping smoking among regular smokers. We found no association between clean indoor air laws and smoking cessation nor between taxes and clean indoor air laws with lower risk of smoking initiation. Cigarette taxes appear to be effective anti-smoking policies. Some state and local governments do not take full advantage of this effective policy measure.

Comprehensive interventions to reduce occupational hazards among medical staff in the pathology department of five primary hospitals.

OBJECTIVE: To explore comprehensive interventions to reduce occupational hazards among medical staff in the pathology department of five primary hospitals. METHODS: The indoor air quality in the pathology department of five primary hospitals and the health status of staff were investigated and analyzed. Formaldehyde and benzene concentrations in the technical and diagnostic rooms of the pathology departments were analyzed before and after comprehensive interventions. The Environmental Protection Agency risk assessment paradigm was used to assess the health risks from occupational exposure to benzene and formaldehyde. Consequently, considering the local environment, targeted comprehensive intervention measures were developed, including optimizing management, raising awareness, updating equipment, and replacing reagents. RESULTS: Eye discomfort was higher among technicians in the pathology department than among clinical medical staff (P < 0.05). Before comprehensive interventions, formaldehyde concentrations were higher in the technical room than in the diagnostic room at the five primary hospitals (P < 0.05). However, compared to before interventions, formaldehyde and benzene concentrations in both rooms were significantly lower after comprehensive interventions. Furthermore, although medium risks of occupational exposure to benzene and formaldehyde remained in both rooms before and after comprehensive interventions, the risk values before interventions were higher than after comprehensive interventions. The staff of the technical rooms showed higher risk values that those of the diagnostic rooms before and after comprehensive interventions. Similarly, although hazard quotient (HQ) values for occupational exposure to benzene and formaldehyde were < 1 in both the technical and diagnostic rooms before and after comprehensive interventions, with lower noncarcinogenic risks, the values were higher before than after comprehensive interventions. Moreover, staff in the technical room had higher HQ values before and after comprehensive interventions than those in the diagnostic room. The use of environmentally friendly reagents for the preparation of frozen sections was effective. CONCLUSION: Comprehensive interventions significantly reduced occupational hazards among staff at the pathology department of five primary hospitals, which is of great practical significance to protect the health of staff.

A new chapter of healthy indoor air: antiviral air treatments.

Aerosol transmission remains a major challenge for the control of respiratory viruses. To date, prevention strategies include masks, vaccinations, physical distancing, travel restrictions, and lockdowns. Such measures are effective but come with heavy societal burdens and rely on public compliance. Additionally, most are simply not suitable as long-term measures. Other strategies evolve around the concept of improved indoor air quality and involve ventilation, relative humidity (RH) control, and air filtration. Unfortunately, natural ventilation increases exposure to airborne pollutants and vector-borne diseases, and incurs substantial energy losses in colder months. Mechanical ventilation concepts, including regular air changes and filtration, are effective but costly, and often require expensive engineering solutions and widespread renovations. Alternative options to reduce the spread of emerging and seasonal infections are sorely needed. In this issue of EMBO Molecular Medicine, Styles et al (2023) describe the use of propylene glycol (PG) to inactivate infectious bioaerosols and virus-containing droplets deposited on surfaces.

Perspectives on human movement considerations in indoor airflow assessment: a comprehensive data-driven systematic review.

Understanding particle dispersion characteristics in indoor environments is crucial for revising infection prevention guidelines through optimized engineering control. The secondary wake flow induced by human movements can disrupt the local airflow field, which enhances particle dispersion within indoor spaces. Over the years, researchers have explored the impact of human movement on indoor air quality (IAQ) and identified noteworthy findings. However, there is a lack of a comprehensive review that systematically synthesizes and summarizes the research in this field. This paper aims to fill that gap by providing an overview of the topic and shedding light on emerging areas. Through a systematic review of relevant articles from the Web of Science database, the study findings reveal an emerging trend and current research gaps on the topic titled Impact of Human Movement in Indoor Airflow (HMIA). As an overview, this paper explores the effect of human movement on human microenvironments and particle resuspension in indoor environments. It delves into the currently available methods for assessing the HMIA and proposes the integration of IoT sensors for potential indoor airflow monitoring. The present study also emphasizes incorporating human movement into ventilation studies to achieve more realistic predictions and yield more practical measures. This review advances knowledge and holds significant implications for scientific and public communities. It identifies future research directions and facilitates the development of effective ventilation strategies to enhance indoor environments and safeguard public health.

[Revision and prospect of "Standards for indoor air quality（GB/T 18883-2022）" in China].

The formulation and revision of the detection methods of indoor air quality standards is an important, rigorous and delicate endeavor. The standards for indoor air quality (GB/T 18883-2022) were issued by the State Administration of Market Regulation and the Standardization Administration on July 11, 2022, and implemented on February 1, 2023 by replacing indoor air quality standards (GB/T 18883-2002). The revised standard specifies hygienic requirements for physical, chemical, biological and radioactive indicators in indoor air and the corresponding test methods. This article interpreted the revision background, drafting principles, main indicators and methods, as well as the revision basis of the standards. Recommendations for the implementation of the standards are also proposed.

[Study on revision of standard limits for benzene in"Standards for indoor air quality（GB/T 18883-2022）"in China].

Benzene, as a major indoor pollutant, has received widespread attention. In order to better control indoor benzene pollution and protect people's health, the limit value of benzene in the"Standards for indoor air quality (GB/T 18883-2022)'' was reduced from 0.11 mg/m3 to 0.03 mg/m3. This study reviewed and discussed the relevant technical contents of the determination of benzene limit value, including the exposure status of benzene, health effects, and derivation of the limit value. It also proposed prospects for the future direction of formulating indoor air benzene standards.

[Study on revision of standard limits for nitrogen dioxide in "Standards for indoor air quality（GB/T 18883-2022）" in China].

Nitrogen dioxide (NO2) is an important indoor air pollutant, with both outdoor and indoor sources contributing to indoor NO2 exposure levels. Considering the association of high NO2 exposure with adverse health effects, the Standards for indoor air quality (GB/T 18883-2022) have been revised to further restrict indoor NO2 limit values. The 1-h average concentration limit value for NO2 has been reduced from 0.24 mg/m3 to 200 µg/m3.This study analyzed the technical contents related to the determination of the limits of indoor NO2 in Standards for Indoor Air Quality (GB/T 18883-2022), including source, exposure level, health effects, and the process and evidence basis for determining the limit value. It also proposed prospects for the direction for the implementation of the indoor NO2 standard.