Indoor Environments最新文献

Indoor lighting can regulate human mood and sleep, further alleviating mental disorder symptoms. Indoor light intervention (ILI) has been demonstrated as therapeutic for mental disease but lacks standardized guidelines for key parameter settings. This review aims to explore the optimal parameters for widely utilized ILI. We conducted a thorough review of research articles published from 1990 to 2023 in the Web of Science, PubMed, and Scopus databases following the PRISMA guidance. Out of a total of 95728 records, 40 eligible studies were analyzed. We subsequently empirically summarized the ILI’s key parameters (i.e., wavelength, illuminance, and exposure time) into each category and compared the therapeutic effects among different ILI groups within each category. Furthermore, we conducted a multivariate model analysis to identify the optimal parameters further while controlling for confounding factors. Results indicate that ILI was mainly used for treating depressive disorders, accounting for 88% of the included articles. Notably, 450 – 550 nm peak wavelength light exhibited superior therapeutic efficacy compared to other wavelengths. Light illuminance within 2500 – 10000 lux correlated significantly and positively with efficacy. Morning ILI appeared more effective than evening ILI, and the efficacy increased with the number of treatment days. Optimizing light wavelength, illuminance, and exposure time of indoor light intervention can significantly enhance its therapeutic effects on mental illness. Our review provides a fundamental reference for improving the use of indoor light intervention in treating mental disorders and optimizing indoor lighting design for a healthy indoor environment.

Compartmentalization, which refers to air sealing each unit within a building from the exterior and other interior spaces, has been proposed as a strategy to improve indoor air quality and energy efficiency in multifamily buildings. This study collected field data on air tightness and pollutant transfer in three new-construction multifamily buildings in California, which was used to develop a model in CONTAM that simulated the impact of leakage levels, ventilation strategies, and climate zones on inter-unit pollutant transfer in multifamily buildings. Air leakage testing found an average total unit leakage of 0.8 L/s₅₀/m², almost twice as tight as California’s current compartmentalization requirement (1.5 L/s₅₀/m²). Two buildings designed with balanced ventilation systems were measured to have imbalanced continuous unit ventilation flows, which were further imbalanced by intermittent exhaust fan operation. Tracer gas testing in two buildings indicated that only about 1–3% of the total air entering a unit came from each neighbouring unit. Furthermore, all particles were apparently removed along the way, as there was no observable particle matter transfer at the tested air tightness levels (0.6–0.9 L/s₅₀/m²). Modelling results indicated that leakier units led to greater dilution of pollutants generated within the unit but increased gaseous pollutant transfer from neighbouring units. The average concentration of benzene, a proxy gas for cigarette smoke, transferred into non-smoking units from neighbours who did smoke almost doubled, surpassing acceptable exposure levels, in the leaky simulation (2.3 L/s₅₀/m²) compared to the tight simulation (0.8 L/s₅₀/m²). Overall, this study suggests that stricter compartmentalization requirements should be adopted in multifamily building code updates, as tighter requirements appear to be manageable for builders and beneficial for indoor air quality when combined with mechanical ventilation.

Introduction

Approximately 46% of U.S. multiunit housing residents with smoke-free home rules, 29 million persons, experience secondhand smoke infiltration in their apartments. Federal health authorities warn that secondhand smoke exposure in multiunit housing is detrimental to the health of children and nonsmoking adults. However, none of the 50 U.S. States bans smoking in privately-owned multiunit housing, and less than 0.1% of the 91,000 U.S. municipalities do.

Materials and methods

This study investigates the health problems reported by 162 nonsmoking residents residing in 104 multiunit apartments in 71 municipalities in 19 U.S. States and the District of Columbia, plus 2 Canadian Provinces. Smoke infiltration was confirmed for residents of 103 nonsmoking apartments using self-deployed passive nicotine monitors from 2006 to 2023. Another five subjects reported health problems from marijuana smoke infiltration confirmed by self-administered marijuana surface wipe tests. The secondhand smoke levels in smokers’ units are estimated using mathematical modeling.

Results

Nonsmokers complained of eye, nose, throat, and lung irritation, headache, dizziness, nausea, difficulty in breathing, tachycardia, and asthmatic attacks as well as malodors. Many sought medical care and some were hospitalized. Some regarded their apartments as uninhabitable. About 12% resorted to litigation. Nicotine concentrations in subjects’ apartments ranged from 0.001 to 6.60 µg/m³ (geometric mean, 0.028 µg/m³). Modeled PM_2.5 levels for a typical smoker’s apartment estimated air pollution levels ranging from “Very Unhealthy” to “Hazardous” levels of the U.S. Air Quality Index. Marijuana surface wipe tests in 5 units showed Tetrahydrocannabinol (THC) ranging from 1.25 µg/m² to 6.92 µg/m². Reported health effects were similar to those with tobacco complaints.

Conclusions

Secondhand smoke infiltration from smokers’ apartments into nonsmokers’ apartment units in multiunit housing can provoke major morbidity for nonsmoking residents. Nonsmokers’ efforts to eliminate infiltration by sealing of cracks, air cleaning, or increased ventilation proved futile. Building owners and managers need to be educated about protecting nonsmoking residents’ health and welfare from secondhand smoke infiltration. Smoking of tobacco and marijuana products in multiunit housing should be banned.

We perform direct numerical simulations to study the effect of increasing airflow rate on CO₂ concentration in downflow and displacement ventilation in a room with one occupant. Often, CO₂ concentration is used as a proxy for the concentration of bio-aerosols of respiratory droplets, and therefore, tracking the CO₂ concentration in ventilation strategies can be useful to understand and quantify the risk of spread of communicable respiratory illnesses. At low to moderate airflow rates, the flow in the downflow setup is not mixed, but stratified. The CO₂ concentration in the upper and lower layers is determined by the strength of the thermal plume originating from the occupant. We provide a simple theoretical model to predict the height of the stratified interface, the volumetric flux of the ascending plume, and the CO₂ concentration in the lower and upper layers. At very high airflow rates, the flow is well-mixed and the average CO₂ concentration in the room can be predicted with the mixing ventilation assumption. We demonstrate that at low to moderate airflow rates, displacement ventilation more effectively maintains lower CO₂ concentrations in the lower layer compared to downflow ventilation.

House dust mite allergens (HDMAs) are a major allergen that can cause severe adverse health effects, such as allergic rhinitis, asthma, and dermatitis. This study aimed to characterize the HDMA levels in bedding dust from Southeast and East Asian countries and evaluate the impact of hygiene practices on these levels. Bedding dust samples were collected from 29, 82, 32, 31, and 86 households in Indonesia, Malaysia, Thailand, Vietnam, and South Korea, respectively. Of the households in Malaysia and South Korea, 57 each had received mattress care services. The samples were analyzed for Dermatophagoides farinae type 1 (Der f1) and Dermatophagoides pteronyssinus type 1 (Der p1). The detection rates of Der f1 and Der p1 varied among the countries, especially in households that had not received mattress care services. In Indonesia, the detection rates of Der f1 and Der p1 were similar (97%). In Malaysia, Thailand, and Vietnam, the detection rates of Der f1 were higher than those of Der p1. South Korea exhibited the lowest detection rates for both Der f1 (76%) and Der p1 (7%). In Indonesia and Malaysia, the levels of Der p1 were higher than those of Der f1. In Thailand and Vietnam, the levels of Der f1 were higher than those of Der p1. In both Malaysia and South Korea, households that had received mattress care services exhibited lower HDMA levels than those that had not. Furthermore, households serviced within the past month had notably lower HDMA levels than those serviced more than two months prior. This study observed significant regional differences in the detection rates and levels of HDMAs among Southeast and East Asian nations. In addition, the study observed significant decrease in the levels of HDMAs following routine mattress care service, highlighting the pivotal role of consistent hygienic practices for diminishing potential allergenic hazards. However, the study could not identify specific regional factors affecting the type and level of HDMAs.

Semi-volatile organic compounds (SVOCs) and trace metals are found anywhere in indoor environments. This study aimed to characterize phthalates, alternative plasticizers (APs), organophosphate flame retardants (OPFRs), and trace metals in air cleaner-captured house dust (ACCD) and to identify the determinants of contaminant levels in ACCD. In total, 120 ACCD samples were collected from 120 houses in Korea that had used air cleaners for over 1 year. All study participants completed a housing, behavior, and lifestyle-related factors questionnaire. The samples were analyzed for 16 phthalates, five APs, 18 OPFRs, and seven trace metals. There were seven chemicals in phthalates, three in APs, and in OPFRs, with 80 % or more detection rates. None of trace metals were found with the detection rate above 65 %. Among the three chemical groups, phthalates were detected at the highest concentrations (geometric mean [GM] (geometric standard deviation [GSD]): 575 (4.6) μg/g in total), followed by APs (389 (5.3) μg/g in total) and OPFRs (290 (3.6) μg/g in total). Among the trace metals, lead and manganese in the ACCD showed the highest concentrations (GM (GSD): 24.8 (8.1) and 24.2 (7.6) μg/g, respectively) with a detection rate of ∼60 %, followed by arsenic (2.9 (17.7) μg/g). The phthalates and Aps measured in the ACCD were comparable to those found in previous investigations of settled dust collected from houses in Korea. Butylbenzyl phthalate and acetyl tributyl citrate concentrations were significantly higher in homes with diffusers, and di-isobutyl phthalate concentrations were higher in homes with air fresheners(p ≤ 0.05). No other determinants were associated with contaminant levels. As residents are persistently exposed to these ubiquitous contaminants through inhalation, appropriate measures are required to reduce potential exposures.

Exposure to ambient and household fine-particulate matter is identified as a substantial contributor to premature mortality in India, according to the Global Burden of Disease Studies. This study examines the impacts of typical Indian cooking practices on indoor air quality characteristics by monitoring the evolution of fine and ultrafine particle (UFP) concentration in the dining facility of a residential educational institute in India. The monitoring area was spread across the kitchen (zone 1) and the dining hall (zone 2). A combination of validated low-cost PM sensors (LCS), DustTrak8433, and Scanning Mobility Particle Sizer (SMPS) was utilized for real-time data acquisition while using Liquefied Petroleum Gas (LPG) as the cooking fuel. PM_2.5 and UFP concentrations were monitored at 1.3 m and 1.8 m from the floor to assess the vertical variation of pollutants during cooking activities, including breakfast, lunch, and dinner, and processes such as preheating, reheating, stir-frying, and deep-frying. It was found that the prolonged cooking durations involved in high-heat cooking methods like stir-frying and deep-frying resulted in a rise in coarser UFP (300–550 nm) and PM_2.5, causing a higher exposure to PM and UFP concentration. PM_2.5 levels are higher at upper heights during typical cooking processes because of temperature-driven convection currents and hygroscopic growth of particles due to high humidity levels. Air exchange rates (AER) considerably varied by using chimneys and were low during the controlled (closed doors) compared to mixed ventilation (opened doors) conditions. The maximum AER was obtained during lunch (4.3–9.9 h⁻¹) compared to breakfast (-7.8–6.8 h⁻¹) and dinner (0.55–7.9 h⁻¹). The decrement rate of PM_2.5 inside zone 1 was highest during lunch (126 µgm⁻³ h⁻¹), coinciding with the highest AER during mixed ventilation. It is recommended that improving ventilation and better design of the kitchen can reduce the exposure of PM and UFP in commercial and rural area kitchens.

Cannabis smoking and vaping are emerging sources of indoor air pollutants, given the current trends of decriminalization and legalization across different jurisdictions. Secondhand exposure at the drug consumption site and thirdhand effects through the potential transfer of cannabis emissions to a secondary area, are of public health significance. Here, we present data from an exploratory observational study that examined emissions from cannabis smoking and vaping within a realistic indoor environment by analyzing the gas-phase composition of the indoor air. Additionally, we explored the transfer of emissions to another indoor space as individuals departed from the initial drug consumption site. We observed no significant (p-value < 0.1) difference across smoking and vaping samples regarding total primary and transferred effects. Primary emissions of light aromatics and some sesquiterpenoids from cannabis smoking led to median indoor concentration enhancements 1.5 to more than 3 times higher than cannabis vaping. On the other hand, vaping primary indoor concentration enhancements were comparable to or higher than smoking values up to a factor of 4 among monoterpenoids. Sesquiterpenoids and some monoterpenoids showed median non-zero concentration enhancements in the secondary indoor space, underscoring the importance of cannabis emissions’ thirdhand transport effects. The thirdhand transport was more efficient for semivolatile species, which have a higher affinity to consumers’ body and clothing. We observed a positive and significant correlation between cannabis cigarette weight change during smoking and cannabinoids enhancement in the secondary space. Vapers’ puff number was significantly and positively correlated with light aromatics enhancement in the secondary space. The correlation between the time spent within the primary smoking/vaping site and cannabinoids transport was significantly negative. These insights can facilitate the design and implementation of future projects to illustrate further cannabis smoking/vaping impacts on indoor air quality.

The aim of this study was to assess the effectiveness of air cleaning in reducing the risk of respiratory infection in two day care centres using a simple and robust calculation model. Additionally, we aimed to identify potential hotspots for infections in indoor setting and focus countermeasures accordingly. Initial results from an interventional clinical study are provided as proof-of-concept for the model. We constructed a mathematical model to assess the number of persons at risk for airborne infection transmission in day care. Utilizing the model, we used portable air cleaners in two day care units (A and B, number of children participating in the study n = 43) and compared infection incidents between the two intervention units to the rest of the units in city of Helsinki (n = 607). The intervention buildings had mechanical supply and exhaust air ventilation. The risk modelling suggests that the use of air cleaners reduced the expected number of persons at infection transmission risk significantly. At day care centre A the average reduction was 60% (range 52% - 88%) and at day care centre B 53% (range 14% - 59%). During the approximately six month study period, we observed a significant difference in the days absent from day care due to infections between the intervention and reference day care units. On average, the parents were absent from work due to child’s illness in reference day care centers for 5.53 days and 3.77 days in intervention day care centers during the study period (p=0.009). In relative terms the reduction was approximately 32%. Our study offers compelling evidence to support increasing non-infectious air flow rates in daycare centers during periods requiring infection risk management. This can be implemented with portable air cleaners as an effective and cost-efficient strategy for mitigating the spread of respiratory infections among children. The clinical results support the findings suggested by the theoretical model.

Implications and impacts

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  Air cleaning seems to be an effective way to reduce infection risk in day cares

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  Identification of infection risk hotspot will help in desgining the preventive methods

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  Portable air cleaners offer an affordable and versatile solution also in buildings where existing ventilation is insufficient for infection risk management”

This paper investigates the pattern of change in occupants’ satisfaction with the Indoor Environmental Quality (IEQ) of their workspace over time. Analyses were performed on a cumulative (2012–2023) database of responses to a Post-Occupancy Evaluation survey in Australia. 20,400 questionnaire responses from 226 office buildings were classified into five groups based on the length of time respondents had occupied their workspace. Associations between workspace satisfaction and the length of time respondents had occupied their workspace were also analysed for different gender and age cohorts. Our results show that occupant satisfaction generally decreased with the length of time they had been allocated to their present workspaces (the ‘honeymoon-hangover’ effect). People who have occupied their workspace for more than 5 years expressed lower overall satisfaction with their workspace than those who have been there for less than 6 months. The same pattern was observed for occupants’ satisfaction with other IEQ dimensions including building image and maintenance, indoor air quality, spatial comfort, and thermal comfort. This ‘honeymoon-hangover’ effect was evident across genders and age groups. Furthermore, there was negligible difference between the two genders on the ‘honeymoon-hangover’ effect, although thermal comfort and indoor air quality were generally less satisfactory for women than men. Respondents aged 30 yrs or less showed a larger decline in satisfaction over time compared to those over 50-yrs old. Within the 30-year-or-under age group, occupants who had spent more than 5 years at their workspaces consistently registered the lowest satisfaction score across all IEQ dimensions.

Implications and impacts

The findings in this study have significant implications for the design of Post-Occupancy Evaluation (POE) surveys and for facility managers aiming to enhance occupants' satisfaction with their workspace and workplace.