Indoor air最新文献

People generally spend most of their time indoors; thus, household air pollution (HAP), especially indoor air pollution, is of paramount importance. In this study, real-time particulate matter (PM_2.5) monitors were used to collect high temporal resolution concentrations of fine PM_2.5 in different microenvironments from 104 urban and rural households in Guizhou Province to investigate the urban–rural difference in HAP and the contribution of cooking activity to HAP. Results showed that PM_2.5 concentrations among different rural microenvironments varied largely, ranging from 26.10 ± 33.27 (mean ± standard deviation) in the bedroom to 69.20 ± 72.50 μg/m³ in the kitchen while varying slightly across various urban microenvironments, ranging from 32.30 ± 17.5 in the living room to 34.65 ± 16.37 μg/m³ in the kitchen. Cooking activity can rapidly increase PM_2.5 concentrations in the kitchen, whose peaks were at least five times higher than baseline levels. The contribution of cooking to the kitchen PM_2.5 was 18.43 ± 12.17% and 5.39 ± 4.15% in rural and urban homes, respectively. Biomass burning affected indoor PM_2.5 concentrations significantly, where rural households using biomass had the highest PM_2.5 levels than households burning other fuels. This study identified the urban–rural disparities in household PM_2.5 pollution and the contributions of cooking activities to HAP, illustrating the importance of cooking activities to indoor air pollution, which can assist in controlling indoor air pollution.

Background: Volatile organic compounds (VOCs) are indoor and outdoor air pollution, but the VOCs that were shared across chronic respiratory diseases (CRDs) remained unknown. Meanwhile, the mediating roles of system inflammation need to be further explored.

Methods: This study included 9114 adults based on the National Health and Nutrition Examination Survey (NHANES) 2005–2006 and 2011–2018. Internal exposure levels of 14 urinary metabolites of VOC (mVOCs), blood cell count–derived inflammatory biomarkers, and prevalent CRDs, including asthma, chronic bronchitis, and emphysema, were assessed and collected. Associations of single- and multiple-mVOCs with CRDs were assessed by using logistic regression and quantile-based g-computation (QGcomp) methods to select the key and shared mVOCs among CRDs. Mediation effects of system inflammation on mVOC-CRD associations were further evaluated by causal mediation analysis.

Results: Increased levels of total 14 mVOCs were associated with increased risk of chronic bronchitis (OR = 1.62, 95% CI: 1.37–1.91), emphysema (OR = 1.73, 95% CI: 1.27–2.35), and both conditions combined (defined as chronic obstructive pulmonary disease, COPD) (OR = 1.61, 95% CI: 1.37–1.88), but not for asthma (OR = 1.07, 95% CI: 0.94–1.21). In both single- and multiple-mVOC exposure models, 8 key mVOCs were COPD associated, including 6 mVOCs (34MHA, AMCC, CEMA, DHBMA, 3HPMA, and MHBMA3) and 5 mVOCs (34MHA, CYMA, 3HPMA, MA, and MHBMA3) that were associated with increased risk of chronic bronchitis and emphysema, respectively. Particularly, 34MHA, 3HPMA, and MHBMA3 were shared risk factors across chronic bronchitis, emphysema, and COPD. Neutrophils mediated the associations of three shared mVOCs with chronic bronchitis (by 5.20%, 7.80%, 6.30%), emphysema (by 6.90%, 9.30%, 9.70%), and COPD (by 5.80%, 8.90%, 7.70%).

Conclusions: These findings provide valuable insights into the shared risk mVOCs and mediating roles of neutrophils involved in the pathogenesis of CRDs, which can be useful in developing more effective prevention and intervention strategies for CRDs.

In regions experiencing severe cold, inadequate ventilation during winter months often leads to increased concentrations of indoor pollutants. While there have been several studies on indoor particulate matter and inorganic pollutants in such regions, bioaerosol pollution has not been as extensively investigated. This study examines the indoor bioaerosol situation in a university located in one of the severe cold regions in China, focusing on bacteria as a representative pollutant. It investigated random samples of an office and a dormitory (including washrooms) and spanned heating and nonheating periods. The findings indicated that bacterial abundance in the dormitory and office was approximately equivalent. The predominant airborne bacterial communities identified were Proteobacteria, Bacteroidota, Actinobacteriota, Firmicutes, and Myxococcota. Opening windows effectively reduced bacterial concentrations during both heating and nonheating periods. When windows remained closed, bacterial concentrations exceeded the standard by 9.1% during the nonheating period and by 14.3% during the heating period. Furthermore, temperature and relative humidity influenced bacterial particle size, activity, and consequently, aerosol concentrations. In the office, the highest percentage of bioaerosols was observed in particle sizes <1.1 and 1.1–2.1 μm, with smaller percentages observed in other particle sizes. Conversely, the percentage of particle sizes 2.1–3.3 μm in the dormitory was higher. The highest bacterial aerosol concentrations were detected in the morning in both the dormitory and office, during heating and nonheating periods. Bacterial concentrations in the office were lower on weekends than on weekdays, whereas in the dormitory, concentrations were higher on weekends than on weekdays. The above results indicate that indoor bacterial aerosol pollution is serious in winter in severe cold regions, which needs more attention.

In the quest to optimize residential environments for health and sustainability, understanding the interaction between pedestrian dynamics and environmental parameters is crucial. This study delves into this intersection by conducting a detailed spatial-temporal analysis within an apartment building. The research reveals pivotal insights about the relationship between pedestrian flow and environmental quality. Key findings reveal distinct patterns in pedestrian traffic, with two main peaks in early morning and late evening, accounting for approximately 24% of daily movement. The study identifies a pronounced preference for upward elevator use, reflecting residents’ lifestyle and floor-level choices. Importantly, we observed variable correlations between pedestrian flow and environmental pollutants. Pollutants like PM_2.5 and carbon monoxide exhibited weak correlations, while noise, TVOC, formaldehyde, and ozone showed stronger associations with human movement. The research uncovered significant spatial differences in pollutant levels across the building, with higher particulate matter and ozone levels in the seventh-floor elevator room. The data suggest a need for tailored pollution management strategies, especially for noise and hazardous compounds like formaldehyde and ozone, which exceed safety limits in certain areas. Our findings offer critical insights for the design and management of residential environments, emphasizing the importance of considering both pedestrian flow and environmental factors in optimizing living spaces for health and efficiency.

Radon is a source of ionizing radiation that shows a carcinogenic potential. Thus, tracking radon exposure levels in the environment and managing exposure conditions is necessary for reducing the hazards such as lung cancer, which is known to be the second largest impact of radon on humans worldwide. A LR-115 Type II strippable detector for monitoring radon radiation was installed in 30 mud and 26 block houses in the periurban (Duakor) areas in the Cape Coast Metropolis, Central Region, for 3 months to determine the exposure levels. The results showed that block houses (n = 26) had a radon ionization concentration in a range of 125–356 Bq m⁻³ and mean of 221 ± 61.4 Bq m⁻³, which was significantly higher than that of mud houses (n = 30), which ranged from 50.8 to 349 Bq m⁻³, with a mean of 186 ± 13.3 Bq m⁻³. About 80% and 10% of both types of houses showed levels that were above WHO’s lower (100 Bq m⁻³) and upper (300 Bq m⁻³) limits of the annual residential guidelines. Moreover, over 70% of both building types showed annual effective doses of indoor radon levels that were within the action levels (3–10 mSv year⁻¹). The data shows that the occupants have lived in their apartments for more than 10 years, while only about 3.0% have ever received some education on radon. Additional steps to manage indoor radon exposure in the community to avoid lung cancer are necessary.

Surface dust in urban environments is an important carrier and potential source of polycyclic aromatic hydrocarbons (PAHs). However, information regarding PAHs in underground parking garage (UPG) surface dust is still limited. In the present study, a total of 30 surface dust samples were collected from UPGs in apartment communities to assess the content, potential health risks to residents and sources of PAHs. The results showed that the total PAH content in the surface dust in the UPGs ranged from 636.27 to 25448.62 μg/kg, with a mean content of 4097.73 μg/kg. The distribution pattern of PAHs based on ring number exhibited the following order: 2–3 > 5–6 > 4 rings. All these surface dust samples were contaminated with PAHs, and 80% were heavily contaminated (ΣPAH > 1000 μg/kg). Health risk assessment revealed that the mean total carcinogenic risk (TCR) for children and adults was 1.33 × 10⁻⁶ and 1.01 × 10⁻⁶, respectively, indicating that residents suffered acceptable carcinogenic risk. The diagnostic ratios and positive matrix factorization results indicate that pyrogenesis was the primary source of PAHs in UPG surface dust, with diesel combustion, gasoline combustion, vehicular emission, and coal combustion contributing 8.2%, 42.8%, 27.9%, and 21.1%, respectively. These results indicate that effective measures should be implemented to protect local workers and residents from carcinogenic effects.

Proper design and operation of buildings are expected to result in optimal thermal comfort and energy performance at the same time. If occupants are not satisfied with thermal conditions, corrective actions by building managers and maintenance staff may lead to elevated room temperatures with evident energy penalties. Because of complicated technical systems and control logic, it is worth studying how well the design intent has been realised in new office buildings. In this study, thermal comfort was analysed by measurements of draught, room, and supply air temperature as well as with occupant questionnaire surveys in five modern office buildings. Both short- and long-term measurements were conducted to demonstrate problems in the operation and to find potential solutions for improvement. The results revealed an issue of excessive overheating during the heating season despite generally low air velocities. Radiant ceiling panels had the lowest velocities in both summer and winter, while buildings with active chilled beams showed the potential to meet Category II air velocity and temperature requirements. The building with thermally activated building systems experienced the most overheating during the heating season. Occupants were satisfied with the heating season temperatures of 23°C–25°C that can be attributed to lighter clothing (0.7 clo) instead of the standard 1.0 clo. Ventilation supply air and indoor temperature analyses indicate that elevated setpoints have been used to compensate for draught, resulting in overheating. As a measure of improvement to avoid overheating, we propose control curves for room temperature based on the outdoor running mean temperature and for supply air temperature based on the extract air temperature.

Predicting the indoor thermal comfort of people while doing sports might pose challenges, as the combination of high metabolic rate, increased humidity of the space due to physical exercise, and the alternate of more and less intense tasks influence perception. This paper is aimed at comparing environmental data (temperature and relative humidity) and calculating comfort indexes (heat index) and two comfort models (Fanger’s predicted mean value and the adaptive thermal comfort model) with people’s perceptions of the environment. Indoor environmental data for the analysis were collected by monitoring several rooms in eight sports centres in a Mediterranean climate. The thermal sensation votes (TSVs) of the occupants were obtained through an online survey. A detailed explanation of the methodology of the monitoring, creation, and management of the survey and the tools used to analyse the data is provided. Results compare the relation between the TSV and the parameters or indexes calculated. Fanger’s predicted mean vote (PMV) model is not able to correctly predict people’s sensations, neither for low nor for high metabolic rates. Finally, the neutral temperature of the adaptive model for the studied conditions is calculated. Among the studied parameters and indices, temperature exhibits the strongest correlation with the thermal sensation of the occupants. However, occupants did not report a significant sensation regarding humidity in accordance with the objective conditions of the rooms. The heat index also did not show any significant correlation with the TSV. Nevertheless, across a wide range of conditions, including variations in metabolic activities, temperature, and relative humidity, the percentage of thermal dissatisfaction (indicated by “very hot” responses) remains consistently high. Notably, the temperature at which a peak in neutral sensation can be achieved is less than 21° for low metabolic rate activities.

Indoor environments affect occupant hygiene, comfort, and productivity. Special treatments, such as spraying essential oils, disinfectant gases, and water vapor or droplets, have been proposed to improve indoor comfort in recent years. Therefore, a method to control the concentrations of these beneficial substances is required. To control the indoor concentration distribution of various degradable substances emitted indoors, this article proposes a novel method that uses the linear relationship between the source and concentration distributions. The method was evaluated through numerical experiments using CFD. Furthermore, the effects of the deposition (Dep) and decomposition (Dec) of the substances on the performance were assessed. The method successfully determined the optimal emission intensities for each emission source to make the concentration field close to the objective—the uniform distribution—in the experiment. When substances decomposed in the air or were deposited on the walls, the performance of the optimal control decreased compared to the case without Dec or Dep. This indicated that the occurrence of Dec or Dep lowered the optimization performance by enhancing the unevenness of the concentration field in the area near the emission source and far from the source. The Dep case showed relatively lower performance than the Dec case because the Dep occurred more spatially unevenly than the Dec. In addition, the more emission sources employed, the smaller the gap between the objective and the optimized concentration field. This method will help control indoor air quality more efficiently.

Background: Little is known about how exposure to different types of pollution is associated with motor development in children or how pollution may be related to time spent in physical activity, sedentary behaviour—including screen time, and sleep. The purpose of this study was to review the evidence on these associations, especially in light of the World Health Organization (WHO) Guidelines for these behaviours.

Methods: We searched eight electronic databases: CINAHL, Embase, ERIC, Global Health, MEDLINE, PsycINFO, Scopus, and Web of Science, from inception to May 2023. Studies that reported an association between a pollution measure (air, water, noise, or land) and at least one movement behaviour (physical activity, sleep, or sedentary time) or motor development outcome (fine or gross motor) among apparently healthy children from birth to 12 years were included. Eligibility of the studies was assessed, and extracted data was based on the study design, sample characteristics, pollution type, and type of association reported.

Results: The search returned 5358 studies, of which 18 were eligible for inclusion. Most studies were conducted in high-income countries (n = 13). Studies reported measures of outdoor air (n = 7), indoor air (n = 4), land (n = 3), and noise pollution (n = 4). Findings from the review were mixed and inconsistent. Most studies reported associations between a pollution measure and motor development outcomes (n = 12), followed by sleep (n = 5) and physical activity and sedentary behaviour (n = 1).

Conclusions: There is limited evidence regarding associations between pollution measures, 24-h movement behaviours, and motor development. Future research should pay more attention to postnatal exposure to different types of pollution and its impact on healthy levels of physical activity, sedentary behaviour, sleep, and motor development and consider confounders such as geographic location, weather conditions, and country income level.

Trial Registration: PROSPERO: CRD42022340130.