Long-term Variations of Indoor Formaldehyde Concentration and Emission Characteristics of Building Materials in Chinese Residences

The static headspace method using a small enclosed chamber has been extensively used to estimate the emission characteristics of formaldehyde, e.g., emission rates from building materials. The formation of the transient formaldehyde concentration by emission, diffusion and sorption in a small confined chamber was investigated using three-dimensional modelling and numerical analyses. Here, five types of glass desiccators were adopted as the small chamber for the headspace method. The inner geometries of the desiccator with the emission source (the building material) and sorbent (water in a Petri dish) were precisely modelled. Transient numerical analyses were performed to determine the formaldehyde emission from different building materials of the external (evaporative) diffusion control type, molecular diffusion and sorption on the water in the confined desiccators. In order to clarify the effect of the desiccator inner geometry on the formaldehyde emission characteristics, the equivalent diffusion length ( Ld) concept, which could be identified as the representative one-dimensional diffusion length scale, was proposed. The results of the numerical analyses showed that Ld and the formaldehyde concentration in the sorbent solution over a 24 h numerical experiment were significantly affected by the desiccator geometry. These results confirmed that the calibration of the emission rate with external diffusion control using Ld is appropriate when measuring the formaldehyde emission rate in an enclosed desiccator with different geometries.

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Variation of Time-Averaged Indoor and Outdoor Radon Concentrations with Time, Location and Sampling Height

Radiation Protection Dosimetry ◽

10.1093/oxfordjournals.rpd.a080294 ◽

1988 ◽

Vol 24 (1-4) ◽

pp. 317-320 ◽

Cited By ~ 8

Author(s):

L.W. Put ◽

R.J. de Meijer

Keyword(s):

Radon Concentration ◽

Building Materials ◽

Living Room ◽

Sampling Height ◽

Crawl Space ◽

Long Term Variations ◽

Indoor And Outdoor ◽

Radon Concentrations

Abstract To study the long-term variations of indoor and outdoor radon concentrations time-averaged radon concentrations were measured in and around two dwellings over a period of almost five years. The integration times for passive dosemeters ranged from 4 to about 18 months. Also studied was the variation of the concentration in a living room and a crawl space as a function of the position of the dosemeters. The outdoor radon concentration was determined as a function of sampling height and position relative to building materials. The relevance of the results for the measuring practice and for the evaluation of radon surveys is discussed.

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Application of Plastic Wastes in Construction Materials: A Review Using the Concept of Life-Cycle Assessment in the Context of Recent Research for Future Perspectives

Materials ◽

10.3390/ma14133549 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3549

Author(s):

Tulane Rodrigues da Silva ◽

Afonso Rangel Garcez de Azevedo ◽

Daiane Cecchin ◽

Markssuel Teixeira Marvila ◽

Mugahed Amran ◽

...

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Solid Waste ◽

Building Materials ◽

Construction Materials ◽

Plastic Waste ◽

Plastic Wastes ◽

Solid Waste Generation ◽

Alternative Processes

The urbanization process contributes to the growth of solid waste generation and causes an increase in environmental impacts and failures in the management of solid waste. The number of dumps is a concern due to the limited implementation and safe disposal of this waste. The interest in sustainable techniques has been growing in relation to waste management, which is largely absorbed by the civil construction sector. This work aimed to review plastic waste, especially polyethylene terephthalate (PET), that can be incorporated with construction materials, such as concrete, mortars, asphalt mixtures, and paving. The use of life-cycle assessment (LCA) is related, as a tool that allows the sustainability of products and processes to be enhanced in the long term. After analyzing the recent literature, it was identified that studies related to plastic wastes in construction materials concentrate sustainability around the alternative destination of waste. Since the plastic waste from different production chains are obtained, it was possible to affirm the need for a broader assessment, such as the LCA, providing greater quantification of data making the alternative processes and products more sustainable. The study contributes to enhance sustainability in alternative building materials through LCA.

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Fluvial magnetic susceptibility as a proxy for long‐term variations of mountain permafrost development in the Alp‐Carpathian region

Boreas ◽

10.1111/bor.12520 ◽

2021 ◽

Author(s):

Zoltán Püspöki ◽

Philip Leonard Gibbard ◽

Annamária Nádor ◽

Edit Thamó‐Bozsó ◽

Pál Sümegi ◽

...

Keyword(s):

Magnetic Susceptibility ◽

Carpathian Region ◽

Mountain Permafrost ◽

Long Term Variations

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Long-term variations of surface solar radiation in China from routine meteorological observations

Atmospheric Research ◽

10.1016/j.atmosres.2021.105715 ◽

2021 ◽

pp. 105715

Author(s):

Xuefang Yang ◽

Wenmin Qin ◽

Lunche Wang ◽

Ming Zhang ◽

Zigeng Niu

Keyword(s):

Solar Radiation ◽

Surface Solar Radiation ◽

Meteorological Observations ◽

Long Term Variations

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Long-term variations of C1–C5 alkyl nitrates and their sources in Hong Kong

Environmental Pollution ◽

10.1016/j.envpol.2020.116285 ◽

2021 ◽

Vol 270 ◽

pp. 116285

Author(s):

Lewei Zeng ◽

Hai Guo ◽

Xiaopu Lyu ◽

Beining Zhou ◽

Zhenhao Ling ◽

...

Keyword(s):

Hong Kong ◽

Alkyl Nitrates ◽

Long Term Variations

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Application of singular spectrum analysis in reconstruction of the annual signal from GRACE

Journal of Applied Geodesy ◽

10.1515/jag-2020-0005 ◽

2020 ◽

Vol 14 (3) ◽

pp. 295-302

Author(s):

Chuandong Zhu ◽

Wei Zhan ◽

Jinzhao Liu ◽

Ming Chen

Keyword(s):

Time Series ◽

Spectrum Analysis ◽

Singular Spectrum Analysis ◽

Mixture Effect ◽

Singular Spectrum ◽

Grace Data ◽

Terrestrial Water ◽

Annual Signal ◽

Long Term Variations

AbstractThe mixture effect of the long-term variations is a main challenge in single channel singular spectrum analysis (SSA) for the reconstruction of the annual signal from GRACE data. In this paper, a nonlinear long-term variations deduction method is used to improve the accuracy of annual signal reconstructed from GRACE data using SSA. Our method can identify and eliminate the nonlinear long-term variations of the equivalent water height time series recovered from GRACE. Therefore the mixture effect of the long-term variations can be avoided in the annual modes of SSA. For the global terrestrial water recovered from GRACE, the peak to peak value of the annual signal is between 1.4 cm and 126.9 cm, with an average of 11.7 cm. After the long-term and the annual term have been deducted, the standard deviation of residual time series is between 0.9 cm and 9.9 cm, with an average of 2.1 cm. Compared with the traditional least squares fitting method, our method can reflect the dynamic change of the annual signal in global terrestrial water, more accurately with an uncertainty of between 0.3 cm and 2.9 cm.

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