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Indoor Air

Remy Franken, Thomas Maggos, Asimina Stamatelopoulou, Miranda Loh, Eelco Kuijpers, John Bartzis, Suzanne Steinle, John W Cherrie, Anjoeka Pronk
The aim of this study was 1) develop a method for converting particle number concentrations (PNC) obtained by Dylos to PM2.5 mass concentrations, 2) compare this conversion with similar methods available in the literature and 3) compare Dylos PM2.5 obtained using all available conversion methods with gravimetric samples. Data were collected in multiple residences in three European countries using the Dylos and an Aerodynamic Particle Sizer (APS, TSI) in the Netherlands or an Optical Particle Counter (OPC, GRIMM) in Greece...
February 13, 2019: Indoor Air
Yen-Chi Chen, Chun-Hsing Liao, Wan-Tien Shen, Chien Su, Yu-Chiao Wu, Ming-Hsuan Tsai, Shui-Shu Hsiao, Kuo-Pin Yu, Chao-Heng Tseng
A novel antimicrobial composite of zero-valent silver nanoparticles (AgNPs), titania (TiO2 ) and chitosan (CS) was prepared via photochemical deposition of AgNPs on a CS-TiO2 matrix (AgNPs@CS-TiO2 ). Electron microscopy showed that the AgNPs were well dispersed on the CS-TiO2 , with diameters of 6.69-8.84 nm. X-ray photoelectron spectra indicated that most of the AgNPs were reduced to metallic Ag. Fourier-transform infrared spectroscopy indicated that some AgNPs formed a chelate with CS through coordination of Ag+ with the CS amide II groups...
February 9, 2019: Indoor Air
Catherine O'Leary, Yvonne Kluizenaar, Piet Jacobs, Wouter Borsboom, Ian Hall, Benjamin Jones
There is growing awareness that indoor exposure to particulate matter with diameter ≤ 2.5μm (PM2.5 ) is associated with an increased risk of adverse health effects. Cooking is a key indoor source of PM2.5 and an activity conducted daily in most homes. Population scale models can predict occupant exposures to PM2.5 , but these predictions are sensitive to the emission rates used. Reported emission rates are highly variable, and are typically for the cooking of single ingredients and not full meals. Accordingly, there is a need to assess PM2...
February 4, 2019: Indoor Air
Li-Wen Hu, Namratha Gurram, Michael S Bloom, Zhengmin Qian, Steven W Howard, Juilet Iwelunmor, Mohammed Zeeshan, Shao Lin, Bo-Yi Yang, Xiao-Wen Zeng, Kang-Kang Liu, Qian-Sheng Hu, Guang-Hui Dong
We conducted a cross-sectional study to investigate the associations between recent home renovation exposure and lung function in children. We randomly recruited 7,326 school children residing in 24 districts from 7 cities in northeastern China. We collected information about home renovations from parents using a questionnaire and lung function measurements from children using spirometer recordings gathered by trained professionals, and expressed as the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), maximal mid-expiratory flow (MMEF), and peak expiratory flow (PEF)...
February 1, 2019: Indoor Air
Hongyin Chen, Jinhan Mo, Ru Xiao, Enze Tian
Formaldehyde is one of the most common indoor air pollutants in Chinese residences. This study introduces a novel laminated plate with adjustable surface temperature to remove gaseous formaldehyde. The plate is fabricated with activated carbon, polyimide and copper foil via thermal compression. The plate can be regenerated in-situ by applying a direct current to the copper foil. Adsorption-regeneration cycle tests were conducted to evaluate the plate's formaldehyde removal performance. The overall removal efficiency of the fabricated laminated plate with glue mass fraction of 25% and thickness of 1...
January 22, 2019: Indoor Air
Magdalena Kruza, Nicola Carslaw
People are an important source of pollution indoors, through activities such as cleaning, and also from 'natural' emissions from breath and skin. This paper investigates natural emissions in high occupancy environments. Model simulations are performed for a school classroom during a typical summer in a polluted urban area. The results show that classroom occupants have a significant impact on indoor ozone, which increases from ~9 ppb to ~20 ppb when the pupils leave for lunch and decreases to ~14 ppb when they return...
January 21, 2019: Indoor Air
R L Hu, S X Wang, K Aunan, M J Zhao, L Chen, Z H Liu, M H Hansen
High levels of PM2.5 exposure and associated health risks are of great concern in rural China. For this study, we used portable PM2.5 monitors for monitoring concentrations online, recorded personal time-activity patterns, and analyzed the contribution from different microenvironments in rural areas of the Yangtze River Delta, China. The daily exposure levels of rural participants were 66μg/m3 (SD 40) in winter and 65μg/m3 (SD 16) in summer. Indoor exposure levels were usually higher than outdoor levels. The exposure levels during cooking in rural kitchens were 140μg/m3 (SD 116) in winter and 121μg/m3 (SD 70) in summer, the highest in all microenvironments...
January 15, 2019: Indoor Air
Raheleh Givehchi, Juan P Maestre, Chenyang Bi, Dennis Wylie, Ying Xu, Kerry A Kinney, Jeffrey A Siegel
Analysis of the dust from heating, ventilation, and air conditioning (HVAC) filters is a promising long-term sampling method to characterize airborne particle-bound contaminants. This filter forensics (FF) approach provides valuable insights about differences between buildings, but does not allow for an estimation of indoor concentrations. In this investigation, FF is extended to quantitative filter forensics (QFF) by using measurements of the volume of air that passes through the filter and the filter efficiency, to assess the integrated average airborne concentrations of total fungal and bacterial DNA, 36 fungal species, endotoxins, phthalates, and organophosphate esters (OPEs) based on dust extracted from HVAC filters...
January 9, 2019: Indoor Air
Ching-Wen Chang, Yun-Tzu Ting, Yu-Ju Horng
This study assessed the collection efficiency (CE) of two popularly-used sampling devices (BioSampler and Coriolis sampler) for fungal aerosols. Phosphate-buffered saline (PBS) supplemented with or without surfactant (Tween 20, Tween 80 or Triton X-100) and antifoam agent were prepared and used as collection liquids. The agar impactor (BioStage) was simultaneously operated with liquid-based samplers to collect fungi from seven sites located at a university building, public library and animal farming. Fungal concentrations determined by liquid samplers were divided by those by BioStage, and the ratio values represented CE...
January 7, 2019: Indoor Air
W Liu, C Huang, B Z Li, Z H Zhao, X Yang, Q H Deng, X Zhang, H Qian, Y X Sun, F Qu, L F Wang, Z J Lin, C Lu, H Wang, J Wang, J Cai, J L Zhang, C J Sun, J H Mo, L B Weschler, D Norbäck, J Sundell, Y P Zhang
From October 2010 to April 2012, we conducted a cross-sectional study of associations between household environments and childhood health among preschool children in eight Chinese cities. Here we analyze associations of early household renovation with preterm birth (PTB), low birth weight (LBW), term low birth weight (Term-LBW), and small for gestational age (SGA). Parents responded to questions about household renovation and their children's gestational age and birth weight. In the multivariate logistic regression analyses, household renovation in the year before pregnancy was significantly associated with LBW (sample size: N=25,813; adjusted odds ratio (OR) with 95% confidence intervals (CIs): 1...
December 31, 2018: Indoor Air
Amreen Shajahan, Charles H Culp, Brandon Williamson
The indoor environment of a mechanically ventilated hospital building controls infection rates as well as influences patients' healing processes and overall medical outcomes. This review covers the scientific research that has assessed patients' medical outcomes concerning at least one indoor environmental parameter related to building Heating, Ventilation, and Air Conditioning (HVAC) systems, such as indoor air temperature, relative humidity, and indoor air ventilation parameters. Research related to the naturally ventilated hospital buildings was outside the scope of this review article...
December 27, 2018: Indoor Air
X Zhao, Q Chen
The adjoint method can determine design variables of an indoor environment according to the optimal design objective, such as minimal predicted mean vote (PMV) for thermal comfort. The method calculates the gradient of the objective function over the design variables so that the objective function can be minimized along the fastest direction using an optimization algorithm. Since the objective function is controlled by the Reynolds-averaged Navier-Stokes (RANS) equations with the RNG k-ε model during the optimization process, all the corresponding adjoint equations should be solved, rather than the "frozen turbulence" assumption used in previous studies...
December 27, 2018: Indoor Air
Jun-Hyeong Park, Youn-Suk Son, Ki-Hyun Kim
The pollution status of particulate matter (PM) in a subway system and technological trends in their reduction were discussed in this study. The levels of PM2.5 and PM10 are generally found to be higher in the underground platforms and tunnels than those in the outdoor air. It has also been reported that the composition of fine dust in the subway consists of various substances including heavy metals (like Fe), carbonaceous matter, and solvent extractable organic matter (SEOM). It was confirmed that subway dust was created mainly by wearing on wheels, rails, and brakes...
December 26, 2018: Indoor Air
Kirsten Koehler, Nicholas Good, Ander Wilson, Anna Mölter, Brianna F Moore, Taylor Carpenter, Jennifer L Peel, John Volckens
This study investigated the role of microenvironment on personal exposures to black carbon (BC), fine particulate mass (PM2.5 ), carbon monoxide (CO), and particle number concentration (PNC) among adult residents of Fort Collins, Colorado, U.S.A. Forty-four participants carried a backpack containing personal monitoring instruments for eight nonconsecutive 24-hour periods. Exposures were apportioned into five microenvironments: Home, Work, Transit, Eateries, and Other. Personal exposures exhibited wide heterogeneity that was dominated by within-person variability (both day-to-day and between microenvironment variability)...
December 26, 2018: Indoor Air
S Ruggieri, V Longo, C Perrino, S Canepari, G Drago, L L'Abbate, M Balzan, G Cuttitta, G Scaccianoce, R Minardi, G Viegi, F Cibella
This study aimed at surveying lower secondary schools in southern Italy, in a highly polluted area. A community close to an industrial area and three villages in rural areas were investigated. Indoor temperature, relative humidity (RH), gaseous pollutants (CO2 and NO2 ), selected biological pollutants in indoor dust, and the indoor/outdoor mass concentration and elemental composition of PM2.5 were ascertained. Temperature and RH were within, or close to, the comfort range, while CO2 frequently exceeded the threshold of 1,000 ppm, indicating inadequate air exchange rate...
December 23, 2018: Indoor Air
Josefin Persson, Thanh Wang, Jessika Hagberg
The envelope of low-energy buildings is generally constructed with significant amounts of plastics, sealants and insulation materials that are known to contain various chemical additives to improve specific functionalities. A commonly used group of additives are flame retardants to prevent the spread of fire. In this study, decabromodiphenyl ether (BDE-209) and fourteen emerging brominated flame retardants (BFRs) were analyzed in indoor dust, air and on the window surface of newly built low-energy preschools to study their occurrence and distribution...
December 22, 2018: Indoor Air
Kati Huttunen, Anna Julia Wlodarczyk, Jenni Tirkkonen, Santtu Mikkonen, Martin Täubel, Esmeralda Krop, José Jacobs, Juha Pekkanen, Dick Heederik, Jan-Paul Zock, Anne Hyvärinen, Maija-Riitta Hirvonen, Rachel Adams, Tim Jones, Ralf Zimmermann, Kelly BéruBé
Exposure to moisture-damaged indoor environments is associated with adverse respiratory health effects, but responsible factors remain unidentified. In order to explore possible mechanisms behind these effects, the oxidative capacity and haemolytic activity of settled dust samples (n=25) collected from moisture-damaged and non-damaged schools in Spain, The Netherlands and Finland were evaluated and matched against the microbial content of the sample. Oxidative capacity was determined with plasmid scission assay, and haemolytic activity by assessing the damage to isolated human red blood cells...
December 21, 2018: Indoor Air
Per Leanderson
Toxic compounds in cooking fumes could cause respiratory problems. In the present study, the formation of isocyanic acid (ICA), methyl isocyanate (MIC), and hydrogen cyanide (HCN) was studied during the heating of proteins or frying of protein-rich foods. Heating was performed in an experimental setup using a tube oven set at 200-500°C and in a kitchen when foods with different protein content were fried at a temperature around 300°C. ICA, MIC, and HCN were all generated when protein or meat was heated. Individual amino acids were also heated, and there was a significant positive correlation between their respective nitrogen content and the formation of the measured compounds...
December 12, 2018: Indoor Air
Baizhan Li, Chenqiu Du, Hong Liu, Wei Yu, Jie Zheng, Meilan Tan, Zhenxing Jin, Wenjie Li, Jing Wu, Lu Chen, Runming Yao
The extensive research interests in environmental temperature can be linked to human productivity/performance as well as comfort and health; while the mechanisms of physiological indices responding to temperature variations remain incompletely understood. This study adopted a physiological sensory nerve conduction velocity (SCV) as a temperature-sensitive biomarker to explore the thermoregulatory mechanisms of human responding to annual temperatures. The measurements of subjects' SCV (over 600 samples) were conducted in a naturally ventilated environment over all four seasons...
November 30, 2018: Indoor Air
Alan Kabanshi, Mats Sandberg
Research on microclimate ventilation systems, which mostly involve free jets, point to delivery of better ventilation in breathing zones. While the literature is comprehensive, the influence of contaminant entrainment in jet flows and its implications on the delivery of supplied air is not fully addressed. This paper present and discuss entrainment characteristics of a jet issued from a round nozzle (0.05 m diameter), in relation to ventilation, by exploring the velocity and temperature fields of the jet flow...
November 30, 2018: Indoor Air
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